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-rw-r--r--docs/chapter08/08-grammar.md94
-rw-r--r--docs/chapter08/08-graph1.gv107
-rw-r--r--docs/chapter08/08-graph1.json39
-rw-r--r--docs/chapter08/08-graph1.svg174
-rw-r--r--docs/chapter08/08-graph2.gv103
-rw-r--r--docs/chapter08/08-graph2.json39
-rw-r--r--docs/chapter08/08-graph2.svg169
-rw-r--r--docs/chapter08/08-graph3.gv111
-rw-r--r--docs/chapter08/08-graph3.json40
-rw-r--r--docs/chapter08/08-graph3.svg179
-rw-r--r--docs/chapter08/Makefile1
-rw-r--r--docs/chapter08/README.md325
12 files changed, 1381 insertions, 0 deletions
diff --git a/docs/chapter08/08-grammar.md b/docs/chapter08/08-grammar.md
new file mode 100644
index 00000000..00f93e04
--- /dev/null
+++ b/docs/chapter08/08-grammar.md
@@ -0,0 +1,94 @@
+# Grammar for Chapter 8
+
+```antlrv4
+grammar SimpleLanguage;
+
+program
+ : statement+ EOF
+ ;
+
+statement
+ : returnStatement
+ | declStatement
+ | blockStatment
+ | expressionStatement
+ | ifStatement
+ | whileStatement
+ | breakStatement
+ | continueStatment
+ ;
+
+whileStatement
+ : 'while' '(' expression ')' statement
+ ;
+
+breakStatement
+ : 'break' ';'
+ ;
+
+continueStatement
+ : 'continue' ';'
+ ;
+
+ifStatement
+ : 'if' '(' expression ')' statement ('else' statement)?
+ ;
+
+
+expressionStatement
+ : IDENTIFIER '=' expression ';'
+ ;
+
+blockStatement
+ : '{' statement+ '}'
+ ;
+
+declStatement
+ : 'int' IDENTIFIER '=' expression ';'
+ ;
+
+returnStatement
+ : 'return' expression ';'
+ ;
+
+expression
+ : comparisonExpression
+ ;
+
+comparisonExpression
+ : additiveExpression (('==' | '!='| '>'| '<'| '>='| '<=') additiveExpression)*
+ ;
+
+additiveExpression
+ : multiplicativeExpression (('+' | '-') multiplicativeExpression)*
+ ;
+
+multiplicativeExpression
+ : unaryExpression (('*' | '/') unaryExpression)*
+ ;
+
+unaryExpression
+ : ('-') unaryExpression
+ | primaryExpression
+ ;
+
+primaryExpression
+ : IDENTIFIER
+ | INTEGER_LITERAL
+ | 'true'
+ | 'false'
+ | '(' expression ')'
+ ;
+
+INTEGER_LITERAL
+ : [1-9][0-9]*
+ | [0]
+ ;
+
+IDENTIFIER
+ : NON_DIGIT (NON_DIGIT | DIGIT)*
+ ;
+
+NON_DIGIT: [a-zA-Z_];
+DEC_DIGIT: [0-9];
+```
diff --git a/docs/chapter08/08-graph1.gv b/docs/chapter08/08-graph1.gv
new file mode 100644
index 00000000..604ee0fe
--- /dev/null
+++ b/docs/chapter08/08-graph1.gv
@@ -0,0 +1,107 @@
+digraph chapter08 {
+/*
+while(arg < 10) {
+ arg = arg + 1;
+ if (arg == 5)
+ continue;
+ if (arg == 6)
+ break;
+}
+return arg;
+
+*/
+ rankdir=BT;
+ ordering="in";
+ concentrate="true";
+ compound="true";
+ subgraph cluster_Nodes {
+ Start2 [ shape=plaintext label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
+ <TR><TD BGCOLOR="yellow">Start</TD></TR>
+ <TR><TD>
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD PORT="p0" BGCOLOR="yellow">$ctrl</TD><TD PORT="p1">arg</TD></TR>
+ </TABLE>
+ </TD></TR>
+ </TABLE>>
+ ];
+ Stop3 [ shape=box style=filled fillcolor=yellow label="Stop" ];
+ Loop6 [ shape=box style=filled fillcolor=yellow label="Loop" ];
+ Phi_arg8 [ style=filled fillcolor=lightyellow label="&phi;_arg" ];
+ Con_9 [ label="10" ];
+ LT10 [ label="<" ];
+ If11 [ shape=plaintext label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
+ <TR><TD BGCOLOR="yellow">If</TD></TR>
+ <TR><TD>
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD PORT="p0" BGCOLOR="yellow">True</TD><TD PORT="p1" BGCOLOR="yellow">False</TD></TR>
+ </TABLE>
+ </TD></TR>
+ </TABLE>>
+ ];
+ Con_15 [ label="1" ];
+ Add16 [ label="+" ];
+ Con_17 [ label="5" ];
+ EQ18 [ label="==" ];
+ If19 [ shape=plaintext label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
+ <TR><TD BGCOLOR="yellow">If</TD></TR>
+ <TR><TD>
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD PORT="p0" BGCOLOR="yellow">True</TD><TD PORT="p1" BGCOLOR="yellow">False</TD></TR>
+ </TABLE>
+ </TD></TR>
+ </TABLE>>
+ ];
+ Con_26 [ label="6" ];
+ EQ27 [ label="==" ];
+ If28 [ shape=plaintext label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
+ <TR><TD BGCOLOR="yellow">If</TD></TR>
+ <TR><TD>
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD PORT="p0" BGCOLOR="yellow">True</TD><TD PORT="p1" BGCOLOR="yellow">False</TD></TR>
+ </TABLE>
+ </TD></TR>
+ </TABLE>>
+ ];
+ Region34 [ shape=box style=filled fillcolor=yellow label="Region" ];
+ Phi_arg35 [ style=filled fillcolor=lightyellow label="&phi;_arg" ];
+ Region39 [ shape=box style=filled fillcolor=yellow label="Region" ];
+ Return40 [ shape=box style=filled fillcolor=yellow label="Return" ];
+ { rank=same; Loop6;Phi_arg8;}
+ { rank=same; Region34;Phi_arg35;}
+ { rank=same; Region39;}
+ }
+ edge [ fontname=Helvetica, fontsize=8 ];
+ Stop3 -> Return40[taillabel=0 color=red];
+ Loop6 -> Start2:p0[taillabel=1 color=red];
+ Loop6 -> Region39[taillabel=2 color=red constraint=false];
+ Phi_arg8 -> Loop6 [style=dotted taillabel=0];
+ Phi_arg8 -> Start2:p1[taillabel=1];
+ Phi_arg8 -> Add16[taillabel=2 constraint=false];
+ LT10 -> Phi_arg8[taillabel=1];
+ LT10 -> Con_9[taillabel=2];
+ If11 -> Loop6[taillabel=0 color=red];
+ If11 -> LT10[taillabel=1];
+ Add16 -> Phi_arg8[taillabel=1];
+ Add16 -> Con_15[taillabel=2];
+ EQ18 -> Add16[taillabel=1];
+ EQ18 -> Con_17[taillabel=2];
+ If19 -> If11:p0[taillabel=0 color=red];
+ If19 -> EQ18[taillabel=1];
+ EQ27 -> Add16[taillabel=1];
+ EQ27 -> Con_26[taillabel=2];
+ If28 -> If19:p1[taillabel=0 color=red];
+ If28 -> EQ27[taillabel=1];
+ Region34 -> If11:p1[taillabel=1 color=red];
+ Region34 -> If28:p0[taillabel=2 color=red];
+ Phi_arg35 -> Region34 [style=dotted taillabel=0];
+ Phi_arg35 -> Phi_arg8[taillabel=1];
+ Phi_arg35 -> Add16[taillabel=2 constraint=false];
+ Region39 -> If19:p0[taillabel=1 color=red];
+ Region39 -> If28:p1[taillabel=2 color=red];
+ Return40 -> Region34[taillabel=0 color=red];
+ Return40 -> Phi_arg35[taillabel=1];
+}
diff --git a/docs/chapter08/08-graph1.json b/docs/chapter08/08-graph1.json
new file mode 100644
index 00000000..130a79bd
--- /dev/null
+++ b/docs/chapter08/08-graph1.json
@@ -0,0 +1,39 @@
+{
+ "ver": 1,
+ "comp": "chapter08/docs/08-graph1.svg",
+ "step": 1,
+ "roots": [],
+ "scope": 0,
+ "nodes": [
+ {"id": 1, "label": "$ctrl", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 2, "role": "CTRL", "label": null}], "proj": {"par": 2, "idx": 0}},
+ {"id": 2, "label": "Start", "type": null, "kind": "CTRL", "edges": [], "proj": null},
+ {"id": 3, "label": "Stop", "type": null, "kind": "STOP", "edges": [{"idx": 0, "def": 40, "role": "CTRL", "label": null}], "proj": null},
+ {"id": 4, "label": "arg", "type": null, "kind": "DATA", "edges": [{"idx": 0, "def": 2, "role": "DATA", "label": null}], "proj": {"par": 2, "idx": 1}},
+ {"id": 5, "label": "True", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 11, "role": "CTRL", "label": null}], "proj": {"par": 11, "idx": 0}},
+ {"id": 6, "label": "Loop", "type": null, "kind": "LOOP", "edges": [{"idx": 0, "def": 0, "role": "DATA", "label": null}, {"idx": 1, "def": 1, "role": "CTRL", "label": null}, {"idx": 2, "def": 39, "role": "CTRL", "label": null}], "proj": null},
+ {"id": 7, "label": "False", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 11, "role": "CTRL", "label": null}], "proj": {"par": 11, "idx": 1}},
+ {"id": 8, "label": "φ_arg", "type": null, "kind": "PHI", "edges": [{"idx": 0, "def": 6, "role": "ASSOC", "label": null}, {"idx": 1, "def": 4, "role": "DATA", "label": null}, {"idx": 2, "def": 16, "role": "DATA", "label": null}], "proj": null},
+ {"id": 9, "label": "10", "type": null, "kind": "DATA", "edges": [], "proj": null},
+ {"id": 10, "label": "<", "type": null, "kind": "DATA", "edges": [{"idx": 0, "def": 0, "role": "DATA", "label": null}, {"idx": 1, "def": 8, "role": "DATA", "label": null}, {"idx": 2, "def": 9, "role": "DATA", "label": null}], "proj": null},
+ {"id": 11, "label": "If", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 6, "role": "CTRL", "label": null}, {"idx": 1, "def": 10, "role": "DATA", "label": null}], "proj": null},
+ {"id": 12, "label": "True", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 19, "role": "CTRL", "label": null}], "proj": {"par": 19, "idx": 0}},
+ {"id": 13, "label": "False", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 19, "role": "CTRL", "label": null}], "proj": {"par": 19, "idx": 1}},
+ {"id": 14, "label": "True", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 28, "role": "CTRL", "label": null}], "proj": {"par": 28, "idx": 0}},
+ {"id": 15, "label": "1", "type": null, "kind": "DATA", "edges": [], "proj": null},
+ {"id": 16, "label": "+", "type": null, "kind": "DATA", "edges": [{"idx": 0, "def": 0, "role": "DATA", "label": null}, {"idx": 1, "def": 8, "role": "DATA", "label": null}, {"idx": 2, "def": 15, "role": "DATA", "label": null}], "proj": null},
+ {"id": 17, "label": "5", "type": null, "kind": "DATA", "edges": [], "proj": null},
+ {"id": 18, "label": "==", "type": null, "kind": "DATA", "edges": [{"idx": 0, "def": 0, "role": "DATA", "label": null}, {"idx": 1, "def": 16, "role": "DATA", "label": null}, {"idx": 2, "def": 17, "role": "DATA", "label": null}], "proj": null},
+ {"id": 19, "label": "If", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 5, "role": "CTRL", "label": null}, {"idx": 1, "def": 18, "role": "DATA", "label": null}], "proj": null},
+ {"id": 20, "label": "False", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 28, "role": "CTRL", "label": null}], "proj": {"par": 28, "idx": 1}},
+ {"id": 26, "label": "6", "type": null, "kind": "DATA", "edges": [], "proj": null},
+ {"id": 27, "label": "==", "type": null, "kind": "DATA", "edges": [{"idx": 0, "def": 0, "role": "DATA", "label": null}, {"idx": 1, "def": 16, "role": "DATA", "label": null}, {"idx": 2, "def": 26, "role": "DATA", "label": null}], "proj": null},
+ {"id": 28, "label": "If", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 13, "role": "CTRL", "label": null}, {"idx": 1, "def": 27, "role": "DATA", "label": null}], "proj": null},
+ {"id": 34, "label": "Region", "type": null, "kind": "REGION", "edges": [{"idx": 0, "def": 0, "role": "DATA", "label": null}, {"idx": 1, "def": 7, "role": "CTRL", "label": null}, {"idx": 2, "def": 14, "role": "CTRL", "label": null}], "proj": null},
+ {"id": 35, "label": "φ_arg", "type": null, "kind": "PHI", "edges": [{"idx": 0, "def": 34, "role": "ASSOC", "label": null}, {"idx": 1, "def": 8, "role": "DATA", "label": null}, {"idx": 2, "def": 16, "role": "DATA", "label": null}], "proj": null},
+ {"id": 39, "label": "Region", "type": null, "kind": "REGION", "edges": [{"idx": 0, "def": 0, "role": "DATA", "label": null}, {"idx": 1, "def": 12, "role": "CTRL", "label": null}, {"idx": 2, "def": 20, "role": "CTRL", "label": null}], "proj": null},
+ {"id": 40, "label": "Return", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 34, "role": "CTRL", "label": null}, {"idx": 1, "def": 35, "role": "DATA", "label": null}], "proj": null}
+ ],
+ "groups": [
+ {"id": 6, "par": 0, "nodes": [5, 6, 7, 8, 10, 11, 12, 13, 14, 18, 19, 20, 27, 28, 39]}
+ ]
+}
diff --git a/docs/chapter08/08-graph1.svg b/docs/chapter08/08-graph1.svg
new file mode 100644
index 00000000..c398607a
--- /dev/null
+++ b/docs/chapter08/08-graph1.svg
@@ -0,0 +1,174 @@
+<svg aria-label="Compiler graph" width="966" height="1390" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 966 1390" style="font-family: sans-serif;"><style>
+ html, body { height:100%; margin:0; font-family:sans-serif; }
+ .viewer { height:100%; display:grid; grid-template-rows:auto minmax(0,1fr) auto; }
+ .source { padding:8px; border-bottom:1px solid #ccc; }
+ #program { width:min(600px,80vw); vertical-align:middle; }
+ #status { margin-top:4px; }
+ #graph { min-height:0; overflow:hidden; position:relative; background:#fafbfc; }
+ #elk { width:100%; height:100%; }
+ #graph svg { display:block; }
+ .tools { display:flex; flex-wrap:wrap; align-items:center; gap:14px; margin-top:8px; font-size:12px; }
+ .hint { color:#616c78; }
+ .ctrl { color:#b63838; } .mem { color:#2867b2; } .data { color:#536477; }
+ .edge { fill:none; stroke-width:1.5; }
+ .edge.CTRL { stroke-width:2; }
+ .edge.ASSOC { stroke-dasharray:4 4; }
+ .edge.PARSER { stroke-dasharray:5 4; }
+ .parser rect { fill:#f6f0ff; stroke:#7956a5; stroke-width:1.5; stroke-dasharray:5 4; }
+ .edge.selected { stroke-width:3.5; }
+ .edge.bundle { stroke-width:4; }
+ .edge.bundle.selected { stroke-width:6; }
+ .edge-hit { fill:none; stroke:transparent; stroke-width:12; vector-effect:non-scaling-stroke; pointer-events:stroke; cursor:pointer; }
+ .edge-jump { fill:transparent; pointer-events:all; cursor:pointer; }
+ .node { cursor:pointer; }
+ .box { stroke:#758191; stroke-width:1; }
+ .node.held .box { stroke-dasharray:5 3; }
+ .node.near .box { stroke:#c18221; stroke-width:2; }
+ .node.focus .box { stroke:#9c4900; stroke-width:3; }
+ .node.selected .box { stroke:#1569b9; stroke-width:3; }
+ .node.folded .box { stroke-width:4; }
+ .node.folding .box { fill:#f4ccd7; }
+ .fold-tag { font-size:9px; font-weight:700; fill:#963751; }
+ .peep-area { fill:#fff3d9; fill-opacity:.8; stroke:#c18221; stroke-width:2; pointer-events:none; }
+ .node.peep-edit .box { stroke:#9c4900; stroke-width:3; }
+ .node.error .box { stroke:#b42318; stroke-width:4; }
+ #event.error { color:#b42318; font-weight:600; white-space:pre-wrap; overflow-wrap:anywhere; }
+ .peep-ghosts { pointer-events:none; }
+ .region-box { stroke:#9da9b8; stroke-width:1.5; }
+ .fold-btn { cursor:pointer; }
+ .fold-btn rect { fill:white; stroke:#596674; }
+ .fold-btn text { font-size:14px; fill:#152330; }
+ .fold-btn:focus rect { stroke:#1569b9; stroke-width:2; }
+ .shortcut { cursor:pointer; }
+ .shortcut path { fill:none; stroke-width:1.5; }
+ .shortcut rect { fill:#fff8ec; stroke:#b63838; stroke-dasharray:3 2; }
+ .shortcut text { font-size:11px; fill:#783030; }
+ .shortcut.selected rect, .shortcut:focus rect { stroke-width:2.5; }
+ .label { font-size:12px; fill:#152330; font-weight:600; }
+ .node-id { font-size:10px; fill:#596674; font-weight:400; }
+ .type { font-size:11px; fill:#455768; }
+ .port { stroke:#536477; stroke-width:1; }
+ .row { stroke:#b6afcf; stroke-width:1; }
+ .bind { font-size:12px; fill:#152330; }
+ .slot { font-size:10px; fill:#364352; paint-order:stroke; stroke:#fafbfc; stroke-width:3; }
+ #detail { position:absolute; top:8px; right:8px; margin:0; padding:12px; max-width:320px;
+ max-height:45%; overflow:auto; white-space:pre-wrap; overflow-wrap:anywhere;
+ background:#fffffff2; border:1px solid #bac5d0; border-radius:4px; font-size:12px; }
+ .controls { display:flex; flex-wrap:wrap; justify-content:center; align-items:center; gap:6px; padding:6px; }
+ .button { color:white; background:black; font-size:20px; min-width:30px; }
+ .button:disabled { background:grey; }
+ .count { font-size:20px; min-width:35px; text-align:center; }
+ #N { width:6ch; }
+ #scrub { width:clamp(120px,35vw,600px); }
+ </style><defs><marker id="arrow-CTRL" viewBox="0 -4 8 8" refX="8" refY="0" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path d="M0,-4L8,0L0,4Z" fill="#b63838"/></marker><marker id="arrow-DATA" viewBox="0 -4 8 8" refX="8" refY="0" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path d="M0,-4L8,0L0,4Z" fill="#536477"/></marker><marker id="arrow-MEM" viewBox="0 -4 8 8" refX="8" refY="0" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path d="M0,-4L8,0L0,4Z" fill="#2867b2"/></marker><marker id="arrow-ASSOC" viewBox="0 -4 8 8" refX="8" refY="0" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path d="M0,-4L8,0L0,4Z" fill="#9396a3"/></marker><marker id="arrow-PARSER" viewBox="0 -4 8 8" refX="8" refY="0" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path d="M0,-4L8,0L0,4Z" fill="#7956a5"/></marker></defs><rect width="100%" height="100%" fill="rgb(250, 251, 252)"/><g><g class="regions" style="opacity: 1;"><g class="region" transform="translate(34,269)"><rect class="region-box" rx="8" width="667" height="810" fill="#f1f6fc"/></g></g><rect class="peep-area" rx="36" style="opacity: 0;"/><g class="edges"><path class="edge CTRL" id="e3i0" d="M409,1289 C409,1313 483,1316 483,1340" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#3[0] → #40 · CTRL</title></path><path class="edge CTRL" id="e6i1" d="M148,216 L148,339" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#6[1] → #1 · CTRL</title></path><path class="edge CTRL" id="e6i2" d="M319,1044 L319,1049 Q319,1054 324,1054 L681,1054 Q689,1054 689,1046 L689,330 Q689,322 681,322 L186,322 Q178,322 178,330 L178,342" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#6[2] → #39 · CTRL</title></path><path class="edge DATA" id="e8i1" d="M268,216 L268,221 Q268,226 273,226 L274,226 Q280,226 280,232 L280,339" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#8[1] → #4 · DATA</title></path><path class="edge DATA" id="e8i2" d="M578,200.33333333333331 L578,205.33333333333331 Q578,210.33333333333331 583,210.33333333333331 L658.1666666666666,210.33333333333331 Q662,210.33333333333331 662,214.16666666666666 L662,214.16666666666666 Q662,218 665.8333333333334,218 L671,218 Q679,218 679,226 L679,322 Q679,330 671,330 L326,330 Q320,330 320,336 L320,342" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#8[2] → #16 · DATA</title></path><path class="edge DATA" id="e10i1" d="M300,395 L300,400 Q300,405 305,405 L332,405 Q340,405 340,413 L340,443" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#10[1] → #8 · DATA</title></path><path class="edge DATA" id="e10i2" d="M426,216 L426,221 Q426,226 421,226 L378,226 Q370,226 370,234 L370,443" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#10[2] → #9 · DATA</title></path><path class="edge CTRL" id="e11i0" d="M148,395 L148,547" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#11[0] → #6 · CTRL</title></path><path class="edge DATA" id="e11i1" d="M340,499 L340,504 Q340,509 335,509 L236,509 Q228,509 228,517 L228,547" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#11[1] → #10 · DATA</title></path><path class="edge DATA" id="e16i1" d="M300,395 L300,400 Q300,405 295,405 L167,405 Q159,405 159,413 L159,501 Q159,509 151,509 L65,509 Q57,509 57,517 L57,1096 Q57,1104 49,1104 L32,1104 Q24,1104 24,1096 L24,92 Q24,84 32,84 L570,84 Q578,84 578,92 L578,147.33333333333331" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#16[1] → #8 · DATA</title></path><path class="edge DATA" id="e16i2" d="M608,74 L608,147.33333333333331" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#16[2] → #15 · DATA</title></path><path class="edge DATA" id="e18i1" d="M578,203.33333333333331 L578,238 Q578,246 570,246 L535,246 Q527,246 527,254 L527,561.6666666666666" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#18[1] → #16 · DATA</title></path><path class="edge DATA" id="e18i2" d="M730,216 L730,221 Q730,226 725,226 L616,226 Q608,226 608,234 L608,501 Q608,509 600,509 L565,509 Q557,509 557,517 L557,561.6666666666666" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#18[2] → #17 · DATA</title></path><path class="edge CTRL" id="e19i0" d="M128,647 L128,652 Q128,657 133,657 L331,657 Q339,657 339,665 L339,695" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#19[0] → #5 · CTRL</title></path><path class="edge DATA" id="e19i1" d="M527,617.6666666666666 L527,649 Q527,657 519,657 L427,657 Q419,657 419,665 L419,695" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#19[1] → #18 · DATA</title></path><path class="edge DATA" id="e27i1" d="M578,203.33333333333331 L578,238 Q578,246 586,246 L589,246 Q597,246 597,254 L597,709.6666666666667" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#27[1] → #16 · DATA</title></path><path class="edge DATA" id="e27i2" d="M882,216 L882,228 Q882,236 874,236 L635,236 Q627,236 627,244 L627,709.6666666666667" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#27[2] → #26 · DATA</title></path><path class="edge CTRL" id="e28i0" d="M439,795 L439,843" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#28[0] → #13 · CTRL</title></path><path class="edge DATA" id="e28i1" d="M597,765.6666666666667 L597,797 Q597,805 589,805 L527,805 Q519,805 519,813 L519,843" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#28[1] → #27 · DATA</title></path><path class="edge CTRL" id="e34i1" d="M248,647 L248,1086 Q248,1094 256,1094 L381,1094 Q389,1094 389,1102 L389,1132" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#34[1] → #7 · CTRL</title></path><path class="edge CTRL" id="e34i2" d="M419,943 L419,1132" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#34[2] → #14 · CTRL</title></path><path class="edge DATA" id="e35i1" d="M300,395 L300,400 Q300,405 295,405 L167,405 Q159,405 159,413 L159,501 Q159,509 151,509 L65,509 Q57,509 57,517 L57,1096 Q57,1104 65,1104 L513,1104 Q521,1104 521,1112 L521,1132" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#35[1] → #8 · DATA</title></path><path class="edge DATA" id="e35i2" d="M578,203.33333333333331 L578,238 Q578,246 586,246 L703,246 Q711,246 711,254 L711,1086 Q711,1094 703,1094 L569,1094 Q561,1094 561,1102 L561,1132" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#35[2] → #16 · DATA</title></path><path class="edge CTRL" id="e39i1" d="M319,795 L319,991" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#39[1] → #12 · CTRL</title></path><path class="edge CTRL" id="e39i2" d="M539,943 L539,948 Q539,953 534,953 L357,953 Q349,953 349,961 L349,991" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#39[2] → #20 · CTRL</title></path><path class="edge CTRL" id="e40i0" d="M389,1188 L389,1236" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#40[0] → #34 · CTRL</title></path><path class="edge DATA" id="e40i1" d="M541,1188 L541,1193 Q541,1198 536,1198 L437,1198 Q429,1198 429,1206 L429,1236" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#40[1] → #35 · DATA</title></path></g><g class="edge-hits"/><g class="parser" style="opacity: 1;"/><g class="nodes"><g class="node" id="n1" data-id="1" transform="translate(88,166)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>$ctrl</tspan><tspan class="node-id">  #1/0</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#1 $ctrl
+Projection 0 of #2
+Type not computed
+
+[0] → #2 CTRL</title></g><g class="node" id="n2" data-id="2" transform="translate(88,122)" style="opacity: 1;"><path class="box" d="M0,0H240V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="120" y="18"><tspan>Start</tspan><tspan class="node-id">  #2</tspan></text><text class="type" text-anchor="middle" y="35" x="120"/><title>#2 Start
+Type not computed
+
+</title></g><g class="node" id="n3" data-id="3" transform="translate(447,1340)" style="opacity: 1;"><path class="box" d="M0,0H72V26H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="36" y="17"><tspan>Stop</tspan><tspan class="node-id">  #3</tspan></text><text class="type" text-anchor="middle" y="35" x="36"/><title>#3 Stop
+Type not computed
+
+[0] → #40 CTRL</title><circle class="port" cx="36" cy="0" r="3" fill="#536477"/><text class="slot" x="36" y="-7" text-anchor="middle">0</text></g><g class="node" id="n4" data-id="4" transform="translate(208,166)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>arg</tspan><tspan class="node-id">  #4/1</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#4 arg
+Projection 1 of #2
+Type not computed
+
+[0] → #2 DATA</title></g><g class="node" id="n5" data-id="5" transform="translate(68,597)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>True</tspan><tspan class="node-id">  #5/0</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#5 True
+Projection 0 of #11
+Type not computed
+
+[0] → #11 CTRL</title></g><g class="node" id="n6" data-id="6" transform="translate(88,345)" style="opacity: 1;"><path class="box" d="M20,0H100Q120,0 120,20V24Q120,44 100,44H20Q0,44 0,24V20Q0,0 20,0Z" fill="#ffe0ab"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>Loop</tspan><tspan class="node-id">  #6</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#6 Loop
+Type not computed
+
+[0] → — DATA
+[1] → #1 CTRL
+[2] → #39 CTRL</title><circle class="port" cx="30" cy="-3" r="3" fill="white"/><circle class="port" cx="60" cy="-3" r="3" fill="#536477"/><circle class="port" cx="90" cy="-3" r="3" fill="#536477"/><text class="slot" x="30" y="-10" text-anchor="middle">0</text><text class="slot" x="60" y="-10" text-anchor="middle">1</text><text class="slot" x="90" y="-10" text-anchor="middle">2</text></g><g class="node" id="n7" data-id="7" transform="translate(188,597)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>False</tspan><tspan class="node-id">  #7/1</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#7 False
+Projection 1 of #11
+Type not computed
+
+[0] → #11 CTRL</title></g><g class="node" id="n8" data-id="8" transform="translate(240,345)" style="opacity: 1;"><path class="box" d="M12,0H108L120,22L108,44H12L0,22Z" fill="#f5e4fa"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>φ_arg</tspan><tspan class="node-id">  #8</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#8 φ_arg
+Type not computed
+
+[0] → #6 ASSOC
+[1] → #4 DATA
+[2] → #16 DATA</title><circle class="port" cx="-3" cy="22" r="3" fill="#536477"/><circle class="port" cx="40" cy="-3" r="3" fill="#536477"/><circle class="port" cx="80" cy="-3" r="3" fill="#536477"/><path class="reg" fill="none" stroke="#b63838" d="M-3,22H-18m4,-3l-4,3l4,3"><title>[0] → #6</title></path><text class="slot" x="-10" y="15" text-anchor="middle">0</text><text class="slot" x="40" y="-10" text-anchor="middle">1</text><text class="slot" x="80" y="-10" text-anchor="middle">2</text></g><g class="node" id="n9" data-id="9" transform="translate(366,166)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>10</tspan><tspan class="node-id">  #9</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#9 10
+Type not computed
+
+</title></g><g class="node" id="n10" data-id="10" transform="translate(280,449)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>&lt;</tspan><tspan class="node-id">  #10</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#10 &lt;
+Type not computed
+
+[0] → — DATA
+[1] → #8 DATA
+[2] → #9 DATA</title><circle class="port" cx="30" cy="-3" r="3" fill="white"/><circle class="port" cx="60" cy="-3" r="3" fill="#536477"/><circle class="port" cx="90" cy="-3" r="3" fill="#536477"/><text class="slot" x="30" y="-10" text-anchor="middle">0</text><text class="slot" x="60" y="-10" text-anchor="middle">1</text><text class="slot" x="90" y="-10" text-anchor="middle">2</text></g><g class="node" id="n11" data-id="11" transform="translate(68,553)" style="opacity: 1;"><path class="box" d="M0,0H240V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="120" y="18"><tspan>If</tspan><tspan class="node-id">  #11</tspan></text><text class="type" text-anchor="middle" y="35" x="120"/><title>#11 If
+Type not computed
+
+[0] → #6 CTRL
+[1] → #10 DATA</title><circle class="port" cx="80" cy="-3" r="3" fill="#536477"/><circle class="port" cx="160" cy="-3" r="3" fill="#536477"/><text class="slot" x="80" y="-10" text-anchor="middle">0</text><text class="slot" x="160" y="-10" text-anchor="middle">1</text></g><g class="node" id="n12" data-id="12" transform="translate(259,745)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>True</tspan><tspan class="node-id">  #12/0</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#12 True
+Projection 0 of #19
+Type not computed
+
+[0] → #19 CTRL</title></g><g class="node" id="n13" data-id="13" transform="translate(379,745)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>False</tspan><tspan class="node-id">  #13/1</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#13 False
+Projection 1 of #19
+Type not computed
+
+[0] → #19 CTRL</title></g><g class="node" id="n14" data-id="14" transform="translate(359,893)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>True</tspan><tspan class="node-id">  #14/0</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#14 True
+Projection 0 of #28
+Type not computed
+
+[0] → #28 CTRL</title></g><g class="node" id="n15" data-id="15" transform="translate(548,24)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>1</tspan><tspan class="node-id">  #15</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#15 1
+Type not computed
+
+</title></g><g class="node" id="n16" data-id="16" transform="translate(518,153.33333333333331)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>+</tspan><tspan class="node-id">  #16</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#16 +
+Type not computed
+
+[0] → — DATA
+[1] → #8 DATA
+[2] → #15 DATA</title><circle class="port" cx="30" cy="-3" r="3" fill="white"/><circle class="port" cx="60" cy="-3" r="3" fill="#536477"/><circle class="port" cx="90" cy="-3" r="3" fill="#536477"/><text class="slot" x="30" y="-10" text-anchor="middle">0</text><text class="slot" x="60" y="-10" text-anchor="middle">1</text><text class="slot" x="90" y="-10" text-anchor="middle">2</text></g><g class="node" id="n17" data-id="17" transform="translate(670,166)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>5</tspan><tspan class="node-id">  #17</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#17 5
+Type not computed
+
+</title></g><g class="node" id="n18" data-id="18" transform="translate(467,567.6666666666666)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>==</tspan><tspan class="node-id">  #18</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#18 ==
+Type not computed
+
+[0] → — DATA
+[1] → #16 DATA
+[2] → #17 DATA</title><circle class="port" cx="30" cy="-3" r="3" fill="white"/><circle class="port" cx="60" cy="-3" r="3" fill="#536477"/><circle class="port" cx="90" cy="-3" r="3" fill="#536477"/><text class="slot" x="30" y="-10" text-anchor="middle">0</text><text class="slot" x="60" y="-10" text-anchor="middle">1</text><text class="slot" x="90" y="-10" text-anchor="middle">2</text></g><g class="node" id="n19" data-id="19" transform="translate(259,701)" style="opacity: 1;"><path class="box" d="M0,0H240V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="120" y="18"><tspan>If</tspan><tspan class="node-id">  #19</tspan></text><text class="type" text-anchor="middle" y="35" x="120"/><title>#19 If
+Type not computed
+
+[0] → #5 CTRL
+[1] → #18 DATA</title><circle class="port" cx="80" cy="-3" r="3" fill="#536477"/><circle class="port" cx="160" cy="-3" r="3" fill="#536477"/><text class="slot" x="80" y="-10" text-anchor="middle">0</text><text class="slot" x="160" y="-10" text-anchor="middle">1</text></g><g class="node" id="n20" data-id="20" transform="translate(479,893)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>False</tspan><tspan class="node-id">  #20/1</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#20 False
+Projection 1 of #28
+Type not computed
+
+[0] → #28 CTRL</title></g><g class="node" id="n26" data-id="26" transform="translate(822,166)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>6</tspan><tspan class="node-id">  #26</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#26 6
+Type not computed
+
+</title></g><g class="node" id="n27" data-id="27" transform="translate(537,715.6666666666667)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>==</tspan><tspan class="node-id">  #27</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#27 ==
+Type not computed
+
+[0] → — DATA
+[1] → #16 DATA
+[2] → #26 DATA</title><circle class="port" cx="30" cy="-3" r="3" fill="white"/><circle class="port" cx="60" cy="-3" r="3" fill="#536477"/><circle class="port" cx="90" cy="-3" r="3" fill="#536477"/><text class="slot" x="30" y="-10" text-anchor="middle">0</text><text class="slot" x="60" y="-10" text-anchor="middle">1</text><text class="slot" x="90" y="-10" text-anchor="middle">2</text></g><g class="node" id="n28" data-id="28" transform="translate(359,849)" style="opacity: 1;"><path class="box" d="M0,0H240V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="120" y="18"><tspan>If</tspan><tspan class="node-id">  #28</tspan></text><text class="type" text-anchor="middle" y="35" x="120"/><title>#28 If
+Type not computed
+
+[0] → #13 CTRL
+[1] → #27 DATA</title><circle class="port" cx="80" cy="-3" r="3" fill="#536477"/><circle class="port" cx="160" cy="-3" r="3" fill="#536477"/><text class="slot" x="80" y="-10" text-anchor="middle">0</text><text class="slot" x="160" y="-10" text-anchor="middle">1</text></g><g class="node" id="n34" data-id="34" transform="translate(329,1138)" style="opacity: 1;"><path class="box" d="M12,0H108L120,44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>Region</tspan><tspan class="node-id">  #34</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#34 Region
+Type not computed
+
+[0] → — DATA
+[1] → #7 CTRL
+[2] → #14 CTRL</title><circle class="port" cx="30" cy="-3" r="3" fill="white"/><circle class="port" cx="60" cy="-3" r="3" fill="#536477"/><circle class="port" cx="90" cy="-3" r="3" fill="#536477"/><text class="slot" x="30" y="-10" text-anchor="middle">0</text><text class="slot" x="60" y="-10" text-anchor="middle">1</text><text class="slot" x="90" y="-10" text-anchor="middle">2</text></g><g class="node" id="n35" data-id="35" transform="translate(481,1138)" style="opacity: 1;"><path class="box" d="M12,0H108L120,22L108,44H12L0,22Z" fill="#f5e4fa"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>φ_arg</tspan><tspan class="node-id">  #35</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#35 φ_arg
+Type not computed
+
+[0] → #34 ASSOC
+[1] → #8 DATA
+[2] → #16 DATA</title><circle class="port" cx="-3" cy="22" r="3" fill="#536477"/><circle class="port" cx="40" cy="-3" r="3" fill="#536477"/><circle class="port" cx="80" cy="-3" r="3" fill="#536477"/><path class="reg" fill="none" stroke="#b63838" d="M-3,22H-18m4,-3l-4,3l4,3"><title>[0] → #34</title></path><text class="slot" x="-10" y="15" text-anchor="middle">0</text><text class="slot" x="40" y="-10" text-anchor="middle">1</text><text class="slot" x="80" y="-10" text-anchor="middle">2</text></g><g class="node" id="n39" data-id="39" transform="translate(259,997)" style="opacity: 1;"><path class="box" d="M12,0H108L120,44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>Region</tspan><tspan class="node-id">  #39</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#39 Region
+Type not computed
+
+[0] → — DATA
+[1] → #12 CTRL
+[2] → #20 CTRL</title><circle class="port" cx="30" cy="-3" r="3" fill="white"/><circle class="port" cx="60" cy="-3" r="3" fill="#536477"/><circle class="port" cx="90" cy="-3" r="3" fill="#536477"/><text class="slot" x="30" y="-10" text-anchor="middle">0</text><text class="slot" x="60" y="-10" text-anchor="middle">1</text><text class="slot" x="90" y="-10" text-anchor="middle">2</text></g><g class="node" id="n40" data-id="40" transform="translate(349,1242)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>Return</tspan><tspan class="node-id">  #40</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#40 Return
+Type not computed
+
+[0] → #34 CTRL
+[1] → #35 DATA</title><circle class="port" cx="40" cy="-3" r="3" fill="#536477"/><circle class="port" cx="80" cy="-3" r="3" fill="#536477"/><text class="slot" x="40" y="-10" text-anchor="middle">0</text><text class="slot" x="80" y="-10" text-anchor="middle">1</text></g></g><g class="region-heads" style="opacity: 1;"><g class="region-head" transform="translate(34,269)"><text class="label" x="26" y="17"><tspan>Loop</tspan><tspan class="node-id">  #6</tspan></text><title>Loop · 15 nodes</title><g class="fold-btn" role="button" tabindex="0" transform="translate(4,4)" aria-label="Fold region #6"><rect width="16" height="16" rx="2"/><text x="8" y="12" text-anchor="middle">−</text><title>Fold region</title></g></g></g><g class="shortcuts" style="opacity: 1;"/><g class="peep-ghosts" pointer-events="none"/></g></svg>
diff --git a/docs/chapter08/08-graph2.gv b/docs/chapter08/08-graph2.gv
new file mode 100644
index 00000000..2fa82523
--- /dev/null
+++ b/docs/chapter08/08-graph2.gv
@@ -0,0 +1,103 @@
+digraph chapter08 {
+/*
+while(arg < 10) {
+ arg = arg + 1;
+ if (arg == 5)
+ continue;
+ if (arg == 6)
+ continue;
+}
+return arg;
+
+*/
+ rankdir=BT;
+ ordering="in";
+ concentrate="true";
+ compound="true";
+ subgraph cluster_Nodes {
+ Start2 [ shape=plaintext label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
+ <TR><TD BGCOLOR="yellow">Start</TD></TR>
+ <TR><TD>
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD PORT="p0" BGCOLOR="yellow">$ctrl</TD><TD PORT="p1">arg</TD></TR>
+ </TABLE>
+ </TD></TR>
+ </TABLE>>
+ ];
+ Stop3 [ shape=box style=filled fillcolor=yellow label="Stop" ];
+ Loop6 [ shape=box style=filled fillcolor=yellow label="Loop" ];
+ Phi_arg8 [ style=filled fillcolor=lightyellow label="&phi;_arg" ];
+ Con_9 [ label="10" ];
+ LT10 [ label="<" ];
+ If11 [ shape=plaintext label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
+ <TR><TD BGCOLOR="yellow">If</TD></TR>
+ <TR><TD>
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD PORT="p0" BGCOLOR="yellow">True</TD><TD PORT="p1" BGCOLOR="yellow">False</TD></TR>
+ </TABLE>
+ </TD></TR>
+ </TABLE>>
+ ];
+ Con_15 [ label="1" ];
+ Add16 [ label="+" ];
+ Con_17 [ label="5" ];
+ EQ18 [ label="==" ];
+ If19 [ shape=plaintext label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
+ <TR><TD BGCOLOR="yellow">If</TD></TR>
+ <TR><TD>
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD PORT="p0" BGCOLOR="yellow">True</TD><TD PORT="p1" BGCOLOR="yellow">False</TD></TR>
+ </TABLE>
+ </TD></TR>
+ </TABLE>>
+ ];
+ Con_26 [ label="6" ];
+ EQ27 [ label="==" ];
+ If28 [ shape=plaintext label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
+ <TR><TD BGCOLOR="yellow">If</TD></TR>
+ <TR><TD>
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD PORT="p0" BGCOLOR="yellow">True</TD><TD PORT="p1" BGCOLOR="yellow">False</TD></TR>
+ </TABLE>
+ </TD></TR>
+ </TABLE>>
+ ];
+ Region34 [ shape=box style=filled fillcolor=yellow label="Region" ];
+ Region38 [ shape=box style=filled fillcolor=yellow label="Region" ];
+ Return39 [ shape=box style=filled fillcolor=yellow label="Return" ];
+ { rank=same; Loop6;Phi_arg8;}
+ { rank=same; Region34;}
+ { rank=same; Region38;}
+ }
+ edge [ fontname=Helvetica, fontsize=8 ];
+ Stop3 -> Return39[taillabel=0 color=red];
+ Loop6 -> Start2:p0[taillabel=1 color=red];
+ Loop6 -> Region38[taillabel=2 color=red constraint=false];
+ Phi_arg8 -> Loop6 [style=dotted taillabel=0];
+ Phi_arg8 -> Start2:p1[taillabel=1];
+ Phi_arg8 -> Add16[taillabel=2 constraint=false];
+ LT10 -> Phi_arg8[taillabel=1];
+ LT10 -> Con_9[taillabel=2];
+ If11 -> Loop6[taillabel=0 color=red];
+ If11 -> LT10[taillabel=1];
+ Add16 -> Phi_arg8[taillabel=1];
+ Add16 -> Con_15[taillabel=2];
+ EQ18 -> Add16[taillabel=1];
+ EQ18 -> Con_17[taillabel=2];
+ If19 -> If11:p0[taillabel=0 color=red];
+ If19 -> EQ18[taillabel=1];
+ EQ27 -> Add16[taillabel=1];
+ EQ27 -> Con_26[taillabel=2];
+ If28 -> If19:p1[taillabel=0 color=red];
+ If28 -> EQ27[taillabel=1];
+ Region34 -> If19:p0[taillabel=1 color=red];
+ Region34 -> If28:p0[taillabel=2 color=red];
+ Region38 -> Region34[taillabel=1 color=red];
+ Region38 -> If28:p1[taillabel=2 color=red];
+ Return39 -> If11:p1[taillabel=0 color=red];
+ Return39 -> Phi_arg8[taillabel=1];
+}
diff --git a/docs/chapter08/08-graph2.json b/docs/chapter08/08-graph2.json
new file mode 100644
index 00000000..6f25aaad
--- /dev/null
+++ b/docs/chapter08/08-graph2.json
@@ -0,0 +1,39 @@
+{
+ "ver": 1,
+ "comp": "chapter08/docs/08-graph2.svg",
+ "step": 1,
+ "roots": [],
+ "scope": 0,
+ "nodes": [
+ {"id": 1, "label": "$ctrl", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 2, "role": "CTRL", "label": null}], "proj": {"par": 2, "idx": 0}},
+ {"id": 2, "label": "Start", "type": null, "kind": "CTRL", "edges": [], "proj": null},
+ {"id": 3, "label": "Stop", "type": null, "kind": "STOP", "edges": [{"idx": 0, "def": 39, "role": "CTRL", "label": null}], "proj": null},
+ {"id": 4, "label": "arg", "type": null, "kind": "DATA", "edges": [{"idx": 0, "def": 2, "role": "DATA", "label": null}], "proj": {"par": 2, "idx": 1}},
+ {"id": 5, "label": "True", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 11, "role": "CTRL", "label": null}], "proj": {"par": 11, "idx": 0}},
+ {"id": 6, "label": "Loop", "type": null, "kind": "LOOP", "edges": [{"idx": 0, "def": 0, "role": "DATA", "label": null}, {"idx": 1, "def": 1, "role": "CTRL", "label": null}, {"idx": 2, "def": 38, "role": "CTRL", "label": null}], "proj": null},
+ {"id": 7, "label": "False", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 11, "role": "CTRL", "label": null}], "proj": {"par": 11, "idx": 1}},
+ {"id": 8, "label": "φ_arg", "type": null, "kind": "PHI", "edges": [{"idx": 0, "def": 6, "role": "ASSOC", "label": null}, {"idx": 1, "def": 4, "role": "DATA", "label": null}, {"idx": 2, "def": 16, "role": "DATA", "label": null}], "proj": null},
+ {"id": 9, "label": "10", "type": null, "kind": "DATA", "edges": [], "proj": null},
+ {"id": 10, "label": "<", "type": null, "kind": "DATA", "edges": [{"idx": 0, "def": 0, "role": "DATA", "label": null}, {"idx": 1, "def": 8, "role": "DATA", "label": null}, {"idx": 2, "def": 9, "role": "DATA", "label": null}], "proj": null},
+ {"id": 11, "label": "If", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 6, "role": "CTRL", "label": null}, {"idx": 1, "def": 10, "role": "DATA", "label": null}], "proj": null},
+ {"id": 12, "label": "True", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 19, "role": "CTRL", "label": null}], "proj": {"par": 19, "idx": 0}},
+ {"id": 13, "label": "False", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 19, "role": "CTRL", "label": null}], "proj": {"par": 19, "idx": 1}},
+ {"id": 14, "label": "True", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 28, "role": "CTRL", "label": null}], "proj": {"par": 28, "idx": 0}},
+ {"id": 15, "label": "1", "type": null, "kind": "DATA", "edges": [], "proj": null},
+ {"id": 16, "label": "+", "type": null, "kind": "DATA", "edges": [{"idx": 0, "def": 0, "role": "DATA", "label": null}, {"idx": 1, "def": 8, "role": "DATA", "label": null}, {"idx": 2, "def": 15, "role": "DATA", "label": null}], "proj": null},
+ {"id": 17, "label": "5", "type": null, "kind": "DATA", "edges": [], "proj": null},
+ {"id": 18, "label": "==", "type": null, "kind": "DATA", "edges": [{"idx": 0, "def": 0, "role": "DATA", "label": null}, {"idx": 1, "def": 16, "role": "DATA", "label": null}, {"idx": 2, "def": 17, "role": "DATA", "label": null}], "proj": null},
+ {"id": 19, "label": "If", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 5, "role": "CTRL", "label": null}, {"idx": 1, "def": 18, "role": "DATA", "label": null}], "proj": null},
+ {"id": 20, "label": "False", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 28, "role": "CTRL", "label": null}], "proj": {"par": 28, "idx": 1}},
+ {"id": 26, "label": "6", "type": null, "kind": "DATA", "edges": [], "proj": null},
+ {"id": 27, "label": "==", "type": null, "kind": "DATA", "edges": [{"idx": 0, "def": 0, "role": "DATA", "label": null}, {"idx": 1, "def": 16, "role": "DATA", "label": null}, {"idx": 2, "def": 26, "role": "DATA", "label": null}], "proj": null},
+ {"id": 28, "label": "If", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 13, "role": "CTRL", "label": null}, {"idx": 1, "def": 27, "role": "DATA", "label": null}], "proj": null},
+ {"id": 34, "label": "Region", "type": null, "kind": "REGION", "edges": [{"idx": 0, "def": 0, "role": "DATA", "label": null}, {"idx": 1, "def": 12, "role": "CTRL", "label": null}, {"idx": 2, "def": 14, "role": "CTRL", "label": null}], "proj": null},
+ {"id": 38, "label": "Region", "type": null, "kind": "REGION", "edges": [{"idx": 0, "def": 0, "role": "DATA", "label": null}, {"idx": 1, "def": 34, "role": "CTRL", "label": null}, {"idx": 2, "def": 20, "role": "CTRL", "label": null}], "proj": null},
+ {"id": 39, "label": "Return", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 7, "role": "CTRL", "label": null}, {"idx": 1, "def": 8, "role": "DATA", "label": null}], "proj": null}
+ ],
+ "groups": [
+ {"id": 6, "par": 0, "nodes": [5, 6, 7, 8, 10, 11, 16]},
+ {"id": 19, "par": 6, "nodes": [12, 13, 14, 18, 19, 20, 27, 28, 34, 38]}
+ ]
+}
diff --git a/docs/chapter08/08-graph2.svg b/docs/chapter08/08-graph2.svg
new file mode 100644
index 00000000..e3d62fb9
--- /dev/null
+++ b/docs/chapter08/08-graph2.svg
@@ -0,0 +1,169 @@
+<svg aria-label="Compiler graph" width="902" height="1452" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 902 1452" style="font-family: sans-serif;"><style>
+ html, body { height:100%; margin:0; font-family:sans-serif; }
+ .viewer { height:100%; display:grid; grid-template-rows:auto minmax(0,1fr) auto; }
+ .source { padding:8px; border-bottom:1px solid #ccc; }
+ #program { width:min(600px,80vw); vertical-align:middle; }
+ #status { margin-top:4px; }
+ #graph { min-height:0; overflow:hidden; position:relative; background:#fafbfc; }
+ #elk { width:100%; height:100%; }
+ #graph svg { display:block; }
+ .tools { display:flex; flex-wrap:wrap; align-items:center; gap:14px; margin-top:8px; font-size:12px; }
+ .hint { color:#616c78; }
+ .ctrl { color:#b63838; } .mem { color:#2867b2; } .data { color:#536477; }
+ .edge { fill:none; stroke-width:1.5; }
+ .edge.CTRL { stroke-width:2; }
+ .edge.ASSOC { stroke-dasharray:4 4; }
+ .edge.PARSER { stroke-dasharray:5 4; }
+ .parser rect { fill:#f6f0ff; stroke:#7956a5; stroke-width:1.5; stroke-dasharray:5 4; }
+ .edge.selected { stroke-width:3.5; }
+ .edge.bundle { stroke-width:4; }
+ .edge.bundle.selected { stroke-width:6; }
+ .edge-hit { fill:none; stroke:transparent; stroke-width:12; vector-effect:non-scaling-stroke; pointer-events:stroke; cursor:pointer; }
+ .edge-jump { fill:transparent; pointer-events:all; cursor:pointer; }
+ .node { cursor:pointer; }
+ .box { stroke:#758191; stroke-width:1; }
+ .node.held .box { stroke-dasharray:5 3; }
+ .node.near .box { stroke:#c18221; stroke-width:2; }
+ .node.focus .box { stroke:#9c4900; stroke-width:3; }
+ .node.selected .box { stroke:#1569b9; stroke-width:3; }
+ .node.folded .box { stroke-width:4; }
+ .node.folding .box { fill:#f4ccd7; }
+ .fold-tag { font-size:9px; font-weight:700; fill:#963751; }
+ .peep-area { fill:#fff3d9; fill-opacity:.8; stroke:#c18221; stroke-width:2; pointer-events:none; }
+ .node.peep-edit .box { stroke:#9c4900; stroke-width:3; }
+ .node.error .box { stroke:#b42318; stroke-width:4; }
+ #event.error { color:#b42318; font-weight:600; white-space:pre-wrap; overflow-wrap:anywhere; }
+ .peep-ghosts { pointer-events:none; }
+ .region-box { stroke:#9da9b8; stroke-width:1.5; }
+ .fold-btn { cursor:pointer; }
+ .fold-btn rect { fill:white; stroke:#596674; }
+ .fold-btn text { font-size:14px; fill:#152330; }
+ .fold-btn:focus rect { stroke:#1569b9; stroke-width:2; }
+ .shortcut { cursor:pointer; }
+ .shortcut path { fill:none; stroke-width:1.5; }
+ .shortcut rect { fill:#fff8ec; stroke:#b63838; stroke-dasharray:3 2; }
+ .shortcut text { font-size:11px; fill:#783030; }
+ .shortcut.selected rect, .shortcut:focus rect { stroke-width:2.5; }
+ .label { font-size:12px; fill:#152330; font-weight:600; }
+ .node-id { font-size:10px; fill:#596674; font-weight:400; }
+ .type { font-size:11px; fill:#455768; }
+ .port { stroke:#536477; stroke-width:1; }
+ .row { stroke:#b6afcf; stroke-width:1; }
+ .bind { font-size:12px; fill:#152330; }
+ .slot { font-size:10px; fill:#364352; paint-order:stroke; stroke:#fafbfc; stroke-width:3; }
+ #detail { position:absolute; top:8px; right:8px; margin:0; padding:12px; max-width:320px;
+ max-height:45%; overflow:auto; white-space:pre-wrap; overflow-wrap:anywhere;
+ background:#fffffff2; border:1px solid #bac5d0; border-radius:4px; font-size:12px; }
+ .controls { display:flex; flex-wrap:wrap; justify-content:center; align-items:center; gap:6px; padding:6px; }
+ .button { color:white; background:black; font-size:20px; min-width:30px; }
+ .button:disabled { background:grey; }
+ .count { font-size:20px; min-width:35px; text-align:center; }
+ #N { width:6ch; }
+ #scrub { width:clamp(120px,35vw,600px); }
+ </style><defs><marker id="arrow-CTRL" viewBox="0 -4 8 8" refX="8" refY="0" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path d="M0,-4L8,0L0,4Z" fill="#b63838"/></marker><marker id="arrow-DATA" viewBox="0 -4 8 8" refX="8" refY="0" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path d="M0,-4L8,0L0,4Z" fill="#536477"/></marker><marker id="arrow-MEM" viewBox="0 -4 8 8" refX="8" refY="0" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path d="M0,-4L8,0L0,4Z" fill="#2867b2"/></marker><marker id="arrow-ASSOC" viewBox="0 -4 8 8" refX="8" refY="0" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path d="M0,-4L8,0L0,4Z" fill="#9396a3"/></marker><marker id="arrow-PARSER" viewBox="0 -4 8 8" refX="8" refY="0" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path d="M0,-4L8,0L0,4Z" fill="#7956a5"/></marker></defs><rect width="100%" height="100%" fill="rgb(250, 251, 252)"/><g><g class="regions" style="opacity: 1;"><g class="region" transform="translate(133,171)"><rect class="region-box" rx="8" width="691" height="1074" fill="#f1f6fc"/></g><g class="region" transform="translate(347,602)"><rect class="region-box" rx="8" width="422" height="606" fill="#f2f7ef"/></g></g><rect class="peep-area" rx="36" style="opacity: 0;"/><g class="edges"><path class="edge CTRL" id="e3i0" d="M356,1351 C356,1375 451,1378 451,1402" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#3[0] → #39 · CTRL</title></path><path class="edge CTRL" id="e6i1" d="M236,118 L236,241" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#6[1] → #1 · CTRL</title></path><path class="edge CTRL" id="e6i2" d="M580,1193 L580,1198 Q580,1203 585,1203 L804,1203 Q812,1203 812,1195 L812,232 Q812,224 804,224 L274,224 Q266,224 266,232 L266,244" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#6[2] → #38 · CTRL</title></path><path class="edge DATA" id="e8i1" d="M356,118 L356,123 Q356,128 361,128 L362,128 Q368,128 368,134 L368,241" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#8[1] → #4 · DATA</title></path><path class="edge DATA" id="e8i2" d="M519,398 L519,403 Q519,408 524,408 L794,408 Q802,408 802,400 L802,240 Q802,232 794,232 L414,232 Q408,232 408,238 L408,244" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#8[2] → #16 · DATA</title></path><path class="edge DATA" id="e10i1" d="M388,297 L388,302 Q388,307 383,307 L324,307 Q316,307 316,315 L316,345" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#10[1] → #8 · DATA</title></path><path class="edge DATA" id="e10i2" d="M84,118 L84,123 Q84,128 89,128 L157,128 Q165,128 165,136 L165,309 Q165,317 173,317 L338,317 Q346,317 346,325 L346,345" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#10[2] → #9 · DATA</title></path><path class="edge CTRL" id="e11i0" d="M236,297 L236,449" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#11[0] → #6 · CTRL</title></path><path class="edge DATA" id="e11i1" d="M316,401 L316,449" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#11[1] → #10 · DATA</title></path><path class="edge DATA" id="e16i1" d="M388,297 L388,302 Q388,307 393,307 L511,307 Q519,307 519,315 L519,345" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#16[1] → #8 · DATA</title></path><path class="edge DATA" id="e16i2" d="M514,118 L514,123 Q514,128 519,128 L541,128 Q549,128 549,136 L549,345" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#16[2] → #15 · DATA</title></path><path class="edge DATA" id="e18i1" d="M519,401 L519,636" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#18[1] → #16 · DATA</title></path><path class="edge DATA" id="e18i2" d="M666,118 L666,123 Q666,128 661,128 L607,128 Q599,128 599,136 L599,413 Q599,421 591,421 L557,421 Q549,421 549,429 L549,636" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#18[2] → #17 · DATA</title></path><path class="edge CTRL" id="e19i0" d="M216,549 L216,554 Q216,559 221,559 L431,559 Q439,559 439,567 L439,740" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#19[0] → #5 · CTRL</title></path><path class="edge DATA" id="e19i1" d="M519,692 L519,740" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#19[1] → #18 · DATA</title></path><path class="edge DATA" id="e27i1" d="M519,401 L519,406 Q519,411 524,411 L689,411 Q697,411 697,419 L697,754.6666666666666" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#27[1] → #16 · DATA</title></path><path class="edge DATA" id="e27i2" d="M818,118 L818,123 Q818,128 813,128 L735,128 Q727,128 727,136 L727,754.6666666666666" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#27[2] → #26 · DATA</title></path><path class="edge CTRL" id="e28i0" d="M539,840 L539,845 Q539,850 534,850 L518,850 Q510,850 510,858 L510,888" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#28[0] → #13 · CTRL</title></path><path class="edge DATA" id="e28i1" d="M697,810.6666666666666 L697,842 Q697,850 689,850 L598,850 Q590,850 590,858 L590,888" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#28[1] → #27 · DATA</title></path><path class="edge CTRL" id="e34i1" d="M419,840 L419,990 Q419,998 427,998 L452,998 Q460,998 460,1006 L460,1036" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#34[1] → #12 · CTRL</title></path><path class="edge CTRL" id="e34i2" d="M490,988 L490,1036" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#34[2] → #14 · CTRL</title></path><path class="edge CTRL" id="e38i1" d="M460,1092 L460,1097 Q460,1102 465,1102 L572,1102 Q580,1102 580,1110 L580,1140" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#38[1] → #34 · CTRL</title></path><path class="edge CTRL" id="e38i2" d="M610,988 L610,1140" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#38[2] → #20 · CTRL</title></path><path class="edge CTRL" id="e39i0" d="M336,549 L336,1298" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#39[0] → #7 · CTRL</title></path><path class="edge DATA" id="e39i1" d="M388,297 L388,302 Q388,307 393,307 L771,307 Q779,307 779,315 L779,1252 Q779,1260 771,1260 L384,1260 Q376,1260 376,1268 L376,1298" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#39[1] → #8 · DATA</title></path></g><g class="edge-hits"/><g class="parser" style="opacity: 1;"/><g class="nodes"><g class="node" id="n1" data-id="1" transform="translate(176,68)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>$ctrl</tspan><tspan class="node-id">  #1/0</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#1 $ctrl
+Projection 0 of #2
+Type not computed
+
+[0] → #2 CTRL</title></g><g class="node" id="n2" data-id="2" transform="translate(176,24)" style="opacity: 1;"><path class="box" d="M0,0H240V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="120" y="18"><tspan>Start</tspan><tspan class="node-id">  #2</tspan></text><text class="type" text-anchor="middle" y="35" x="120"/><title>#2 Start
+Type not computed
+
+</title></g><g class="node" id="n3" data-id="3" transform="translate(415,1402)" style="opacity: 1;"><path class="box" d="M0,0H72V26H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="36" y="17"><tspan>Stop</tspan><tspan class="node-id">  #3</tspan></text><text class="type" text-anchor="middle" y="35" x="36"/><title>#3 Stop
+Type not computed
+
+[0] → #39 CTRL</title><circle class="port" cx="36" cy="0" r="3" fill="#536477"/><text class="slot" x="36" y="-7" text-anchor="middle">0</text></g><g class="node" id="n4" data-id="4" transform="translate(296,68)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>arg</tspan><tspan class="node-id">  #4/1</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#4 arg
+Projection 1 of #2
+Type not computed
+
+[0] → #2 DATA</title></g><g class="node" id="n5" data-id="5" transform="translate(156,499)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>True</tspan><tspan class="node-id">  #5/0</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#5 True
+Projection 0 of #11
+Type not computed
+
+[0] → #11 CTRL</title></g><g class="node" id="n6" data-id="6" transform="translate(176,247)" style="opacity: 1;"><path class="box" d="M20,0H100Q120,0 120,20V24Q120,44 100,44H20Q0,44 0,24V20Q0,0 20,0Z" fill="#ffe0ab"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>Loop</tspan><tspan class="node-id">  #6</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#6 Loop
+Type not computed
+
+[0] → — DATA
+[1] → #1 CTRL
+[2] → #38 CTRL</title><circle class="port" cx="30" cy="-3" r="3" fill="white"/><circle class="port" cx="60" cy="-3" r="3" fill="#536477"/><circle class="port" cx="90" cy="-3" r="3" fill="#536477"/><text class="slot" x="30" y="-10" text-anchor="middle">0</text><text class="slot" x="60" y="-10" text-anchor="middle">1</text><text class="slot" x="90" y="-10" text-anchor="middle">2</text></g><g class="node" id="n7" data-id="7" transform="translate(276,499)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>False</tspan><tspan class="node-id">  #7/1</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#7 False
+Projection 1 of #11
+Type not computed
+
+[0] → #11 CTRL</title></g><g class="node" id="n8" data-id="8" transform="translate(328,247)" style="opacity: 1;"><path class="box" d="M12,0H108L120,22L108,44H12L0,22Z" fill="#f5e4fa"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>φ_arg</tspan><tspan class="node-id">  #8</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#8 φ_arg
+Type not computed
+
+[0] → #6 ASSOC
+[1] → #4 DATA
+[2] → #16 DATA</title><circle class="port" cx="-3" cy="22" r="3" fill="#536477"/><circle class="port" cx="40" cy="-3" r="3" fill="#536477"/><circle class="port" cx="80" cy="-3" r="3" fill="#536477"/><path class="reg" fill="none" stroke="#b63838" d="M-3,22H-18m4,-3l-4,3l4,3"><title>[0] → #6</title></path><text class="slot" x="-10" y="15" text-anchor="middle">0</text><text class="slot" x="40" y="-10" text-anchor="middle">1</text><text class="slot" x="80" y="-10" text-anchor="middle">2</text></g><g class="node" id="n9" data-id="9" transform="translate(24,68)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>10</tspan><tspan class="node-id">  #9</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#9 10
+Type not computed
+
+</title></g><g class="node" id="n10" data-id="10" transform="translate(256,351)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>&lt;</tspan><tspan class="node-id">  #10</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#10 &lt;
+Type not computed
+
+[0] → — DATA
+[1] → #8 DATA
+[2] → #9 DATA</title><circle class="port" cx="30" cy="-3" r="3" fill="white"/><circle class="port" cx="60" cy="-3" r="3" fill="#536477"/><circle class="port" cx="90" cy="-3" r="3" fill="#536477"/><text class="slot" x="30" y="-10" text-anchor="middle">0</text><text class="slot" x="60" y="-10" text-anchor="middle">1</text><text class="slot" x="90" y="-10" text-anchor="middle">2</text></g><g class="node" id="n11" data-id="11" transform="translate(156,455)" style="opacity: 1;"><path class="box" d="M0,0H240V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="120" y="18"><tspan>If</tspan><tspan class="node-id">  #11</tspan></text><text class="type" text-anchor="middle" y="35" x="120"/><title>#11 If
+Type not computed
+
+[0] → #6 CTRL
+[1] → #10 DATA</title><circle class="port" cx="80" cy="-3" r="3" fill="#536477"/><circle class="port" cx="160" cy="-3" r="3" fill="#536477"/><text class="slot" x="80" y="-10" text-anchor="middle">0</text><text class="slot" x="160" y="-10" text-anchor="middle">1</text></g><g class="node" id="n12" data-id="12" transform="translate(359,790)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>True</tspan><tspan class="node-id">  #12/0</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#12 True
+Projection 0 of #19
+Type not computed
+
+[0] → #19 CTRL</title></g><g class="node" id="n13" data-id="13" transform="translate(479,790)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>False</tspan><tspan class="node-id">  #13/1</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#13 False
+Projection 1 of #19
+Type not computed
+
+[0] → #19 CTRL</title></g><g class="node" id="n14" data-id="14" transform="translate(430,938)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>True</tspan><tspan class="node-id">  #14/0</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#14 True
+Projection 0 of #28
+Type not computed
+
+[0] → #28 CTRL</title></g><g class="node" id="n15" data-id="15" transform="translate(454,68)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>1</tspan><tspan class="node-id">  #15</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#15 1
+Type not computed
+
+</title></g><g class="node" id="n16" data-id="16" transform="translate(459,351)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>+</tspan><tspan class="node-id">  #16</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#16 +
+Type not computed
+
+[0] → — DATA
+[1] → #8 DATA
+[2] → #15 DATA</title><circle class="port" cx="30" cy="-3" r="3" fill="white"/><circle class="port" cx="60" cy="-3" r="3" fill="#536477"/><circle class="port" cx="90" cy="-3" r="3" fill="#536477"/><text class="slot" x="30" y="-10" text-anchor="middle">0</text><text class="slot" x="60" y="-10" text-anchor="middle">1</text><text class="slot" x="90" y="-10" text-anchor="middle">2</text></g><g class="node" id="n17" data-id="17" transform="translate(606,68)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>5</tspan><tspan class="node-id">  #17</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#17 5
+Type not computed
+
+</title></g><g class="node" id="n18" data-id="18" transform="translate(459,642)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>==</tspan><tspan class="node-id">  #18</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#18 ==
+Type not computed
+
+[0] → — DATA
+[1] → #16 DATA
+[2] → #17 DATA</title><circle class="port" cx="30" cy="-3" r="3" fill="white"/><circle class="port" cx="60" cy="-3" r="3" fill="#536477"/><circle class="port" cx="90" cy="-3" r="3" fill="#536477"/><text class="slot" x="30" y="-10" text-anchor="middle">0</text><text class="slot" x="60" y="-10" text-anchor="middle">1</text><text class="slot" x="90" y="-10" text-anchor="middle">2</text></g><g class="node" id="n19" data-id="19" transform="translate(359,746)" style="opacity: 1;"><path class="box" d="M0,0H240V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="120" y="18"><tspan>If</tspan><tspan class="node-id">  #19</tspan></text><text class="type" text-anchor="middle" y="35" x="120"/><title>#19 If
+Type not computed
+
+[0] → #5 CTRL
+[1] → #18 DATA</title><circle class="port" cx="80" cy="-3" r="3" fill="#536477"/><circle class="port" cx="160" cy="-3" r="3" fill="#536477"/><text class="slot" x="80" y="-10" text-anchor="middle">0</text><text class="slot" x="160" y="-10" text-anchor="middle">1</text></g><g class="node" id="n20" data-id="20" transform="translate(550,938)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>False</tspan><tspan class="node-id">  #20/1</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#20 False
+Projection 1 of #28
+Type not computed
+
+[0] → #28 CTRL</title></g><g class="node" id="n26" data-id="26" transform="translate(758,68)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>6</tspan><tspan class="node-id">  #26</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#26 6
+Type not computed
+
+</title></g><g class="node" id="n27" data-id="27" transform="translate(637,760.6666666666666)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>==</tspan><tspan class="node-id">  #27</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#27 ==
+Type not computed
+
+[0] → — DATA
+[1] → #16 DATA
+[2] → #26 DATA</title><circle class="port" cx="30" cy="-3" r="3" fill="white"/><circle class="port" cx="60" cy="-3" r="3" fill="#536477"/><circle class="port" cx="90" cy="-3" r="3" fill="#536477"/><text class="slot" x="30" y="-10" text-anchor="middle">0</text><text class="slot" x="60" y="-10" text-anchor="middle">1</text><text class="slot" x="90" y="-10" text-anchor="middle">2</text></g><g class="node" id="n28" data-id="28" transform="translate(430,894)" style="opacity: 1;"><path class="box" d="M0,0H240V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="120" y="18"><tspan>If</tspan><tspan class="node-id">  #28</tspan></text><text class="type" text-anchor="middle" y="35" x="120"/><title>#28 If
+Type not computed
+
+[0] → #13 CTRL
+[1] → #27 DATA</title><circle class="port" cx="80" cy="-3" r="3" fill="#536477"/><circle class="port" cx="160" cy="-3" r="3" fill="#536477"/><text class="slot" x="80" y="-10" text-anchor="middle">0</text><text class="slot" x="160" y="-10" text-anchor="middle">1</text></g><g class="node" id="n34" data-id="34" transform="translate(400,1042)" style="opacity: 1;"><path class="box" d="M12,0H108L120,44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>Region</tspan><tspan class="node-id">  #34</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#34 Region
+Type not computed
+
+[0] → — DATA
+[1] → #12 CTRL
+[2] → #14 CTRL</title><circle class="port" cx="30" cy="-3" r="3" fill="white"/><circle class="port" cx="60" cy="-3" r="3" fill="#536477"/><circle class="port" cx="90" cy="-3" r="3" fill="#536477"/><text class="slot" x="30" y="-10" text-anchor="middle">0</text><text class="slot" x="60" y="-10" text-anchor="middle">1</text><text class="slot" x="90" y="-10" text-anchor="middle">2</text></g><g class="node" id="n38" data-id="38" transform="translate(520,1146)" style="opacity: 1;"><path class="box" d="M12,0H108L120,44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>Region</tspan><tspan class="node-id">  #38</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#38 Region
+Type not computed
+
+[0] → — DATA
+[1] → #34 CTRL
+[2] → #20 CTRL</title><circle class="port" cx="30" cy="-3" r="3" fill="white"/><circle class="port" cx="60" cy="-3" r="3" fill="#536477"/><circle class="port" cx="90" cy="-3" r="3" fill="#536477"/><text class="slot" x="30" y="-10" text-anchor="middle">0</text><text class="slot" x="60" y="-10" text-anchor="middle">1</text><text class="slot" x="90" y="-10" text-anchor="middle">2</text></g><g class="node" id="n39" data-id="39" transform="translate(296,1304)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>Return</tspan><tspan class="node-id">  #39</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#39 Return
+Type not computed
+
+[0] → #7 CTRL
+[1] → #8 DATA</title><circle class="port" cx="40" cy="-3" r="3" fill="#536477"/><circle class="port" cx="80" cy="-3" r="3" fill="#536477"/><text class="slot" x="40" y="-10" text-anchor="middle">0</text><text class="slot" x="80" y="-10" text-anchor="middle">1</text></g></g><g class="region-heads" style="opacity: 1;"><g class="region-head" transform="translate(133,171)"><text class="label" x="26" y="17"><tspan>Loop</tspan><tspan class="node-id">  #6</tspan></text><title>Loop · 17 nodes</title><g class="fold-btn" role="button" tabindex="0" transform="translate(4,4)" aria-label="Fold region #6"><rect width="16" height="16" rx="2"/><text x="8" y="12" text-anchor="middle">−</text><title>Fold region</title></g></g><g class="region-head" transform="translate(347,602)"><text class="label" x="26" y="17"><tspan>If</tspan><tspan class="node-id">  #19</tspan></text><title>If · 10 nodes</title><g class="fold-btn" role="button" tabindex="0" transform="translate(4,4)" aria-label="Fold region #19"><rect width="16" height="16" rx="2"/><text x="8" y="12" text-anchor="middle">−</text><title>Fold region</title></g></g></g><g class="shortcuts" style="opacity: 1;"/><g class="peep-ghosts" pointer-events="none"/></g></svg>
diff --git a/docs/chapter08/08-graph3.gv b/docs/chapter08/08-graph3.gv
new file mode 100644
index 00000000..72ac10a8
--- /dev/null
+++ b/docs/chapter08/08-graph3.gv
@@ -0,0 +1,111 @@
+digraph chapter08 {
+/*
+while(arg < 10) {
+ arg = arg + 1;
+ if (arg == 5)
+ break;
+ if (arg == 6)
+ break;
+}
+return arg;
+
+*/
+ rankdir=BT;
+ ordering="in";
+ concentrate="true";
+ compound="true";
+ subgraph cluster_Nodes {
+ Start2 [ shape=plaintext label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
+ <TR><TD BGCOLOR="yellow">Start</TD></TR>
+ <TR><TD>
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD PORT="p0" BGCOLOR="yellow">$ctrl</TD><TD PORT="p1">arg</TD></TR>
+ </TABLE>
+ </TD></TR>
+ </TABLE>>
+ ];
+ Stop3 [ shape=box style=filled fillcolor=yellow label="Stop" ];
+ Loop6 [ shape=box style=filled fillcolor=yellow label="Loop" ];
+ Phi_arg8 [ style=filled fillcolor=lightyellow label="&phi;_arg" ];
+ Con_9 [ label="10" ];
+ LT10 [ label="<" ];
+ If11 [ shape=plaintext label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
+ <TR><TD BGCOLOR="yellow">If</TD></TR>
+ <TR><TD>
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD PORT="p0" BGCOLOR="yellow">True</TD><TD PORT="p1" BGCOLOR="yellow">False</TD></TR>
+ </TABLE>
+ </TD></TR>
+ </TABLE>>
+ ];
+ Con_15 [ label="1" ];
+ Add16 [ label="+" ];
+ Con_17 [ label="5" ];
+ EQ18 [ label="==" ];
+ If19 [ shape=plaintext label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
+ <TR><TD BGCOLOR="yellow">If</TD></TR>
+ <TR><TD>
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD PORT="p0" BGCOLOR="yellow">True</TD><TD PORT="p1" BGCOLOR="yellow">False</TD></TR>
+ </TABLE>
+ </TD></TR>
+ </TABLE>>
+ ];
+ Region25 [ shape=box style=filled fillcolor=yellow label="Region" ];
+ Phi_arg26 [ style=filled fillcolor=lightyellow label="&phi;_arg" ];
+ Con_28 [ label="6" ];
+ EQ29 [ label="==" ];
+ If30 [ shape=plaintext label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
+ <TR><TD BGCOLOR="yellow">If</TD></TR>
+ <TR><TD>
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD PORT="p0" BGCOLOR="yellow">True</TD><TD PORT="p1" BGCOLOR="yellow">False</TD></TR>
+ </TABLE>
+ </TD></TR>
+ </TABLE>>
+ ];
+ Region36 [ shape=box style=filled fillcolor=yellow label="Region" ];
+ Phi_arg37 [ style=filled fillcolor=lightyellow label="&phi;_arg" ];
+ Return39 [ shape=box style=filled fillcolor=yellow label="Return" ];
+ { rank=same; Loop6;Phi_arg8;}
+ { rank=same; Region25;Phi_arg26;}
+ { rank=same; Region36;Phi_arg37;}
+ }
+ edge [ fontname=Helvetica, fontsize=8 ];
+ Stop3 -> Return39[taillabel=0 color=red];
+ Loop6 -> Start2:p0[taillabel=1 color=red];
+ Loop6 -> If30:p1[taillabel=2 color=red constraint=false];
+ Phi_arg8 -> Loop6 [style=dotted taillabel=0];
+ Phi_arg8 -> Start2:p1[taillabel=1];
+ Phi_arg8 -> Add16[taillabel=2 constraint=false];
+ LT10 -> Phi_arg8[taillabel=1];
+ LT10 -> Con_9[taillabel=2];
+ If11 -> Loop6[taillabel=0 color=red];
+ If11 -> LT10[taillabel=1];
+ Add16 -> Phi_arg8[taillabel=1];
+ Add16 -> Con_15[taillabel=2];
+ EQ18 -> Add16[taillabel=1];
+ EQ18 -> Con_17[taillabel=2];
+ If19 -> If11:p0[taillabel=0 color=red];
+ If19 -> EQ18[taillabel=1];
+ Region25 -> If11:p1[taillabel=1 color=red];
+ Region25 -> If19:p0[taillabel=2 color=red];
+ Phi_arg26 -> Region25 [style=dotted taillabel=0];
+ Phi_arg26 -> Phi_arg8[taillabel=1];
+ Phi_arg26 -> Add16[taillabel=2 constraint=false];
+ EQ29 -> Add16[taillabel=1];
+ EQ29 -> Con_28[taillabel=2];
+ If30 -> If19:p1[taillabel=0 color=red];
+ If30 -> EQ29[taillabel=1];
+ Region36 -> Region25[taillabel=1 color=red];
+ Region36 -> If30:p0[taillabel=2 color=red];
+ Phi_arg37 -> Region36 [style=dotted taillabel=0];
+ Phi_arg37 -> Phi_arg26[taillabel=1];
+ Phi_arg37 -> Add16[taillabel=2 constraint=false];
+ Return39 -> Region36[taillabel=0 color=red];
+ Return39 -> Phi_arg37[taillabel=1];
+} \ No newline at end of file
diff --git a/docs/chapter08/08-graph3.json b/docs/chapter08/08-graph3.json
new file mode 100644
index 00000000..a795c51d
--- /dev/null
+++ b/docs/chapter08/08-graph3.json
@@ -0,0 +1,40 @@
+{
+ "ver": 1,
+ "comp": "chapter08/docs/08-graph3.svg",
+ "step": 1,
+ "roots": [],
+ "scope": 0,
+ "nodes": [
+ {"id": 1, "label": "$ctrl", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 2, "role": "CTRL", "label": null}], "proj": {"par": 2, "idx": 0}},
+ {"id": 2, "label": "Start", "type": null, "kind": "CTRL", "edges": [], "proj": null},
+ {"id": 3, "label": "Stop", "type": null, "kind": "STOP", "edges": [{"idx": 0, "def": 39, "role": "CTRL", "label": null}], "proj": null},
+ {"id": 4, "label": "arg", "type": null, "kind": "DATA", "edges": [{"idx": 0, "def": 2, "role": "DATA", "label": null}], "proj": {"par": 2, "idx": 1}},
+ {"id": 5, "label": "True", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 11, "role": "CTRL", "label": null}], "proj": {"par": 11, "idx": 0}},
+ {"id": 6, "label": "Loop", "type": null, "kind": "LOOP", "edges": [{"idx": 0, "def": 0, "role": "DATA", "label": null}, {"idx": 1, "def": 1, "role": "CTRL", "label": null}, {"idx": 2, "def": 20, "role": "CTRL", "label": null}], "proj": null},
+ {"id": 7, "label": "False", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 11, "role": "CTRL", "label": null}], "proj": {"par": 11, "idx": 1}},
+ {"id": 8, "label": "φ_arg", "type": null, "kind": "PHI", "edges": [{"idx": 0, "def": 6, "role": "ASSOC", "label": null}, {"idx": 1, "def": 4, "role": "DATA", "label": null}, {"idx": 2, "def": 16, "role": "DATA", "label": null}], "proj": null},
+ {"id": 9, "label": "10", "type": null, "kind": "DATA", "edges": [], "proj": null},
+ {"id": 10, "label": "<", "type": null, "kind": "DATA", "edges": [{"idx": 0, "def": 0, "role": "DATA", "label": null}, {"idx": 1, "def": 8, "role": "DATA", "label": null}, {"idx": 2, "def": 9, "role": "DATA", "label": null}], "proj": null},
+ {"id": 11, "label": "If", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 6, "role": "CTRL", "label": null}, {"idx": 1, "def": 10, "role": "DATA", "label": null}], "proj": null},
+ {"id": 12, "label": "True", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 19, "role": "CTRL", "label": null}], "proj": {"par": 19, "idx": 0}},
+ {"id": 13, "label": "False", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 19, "role": "CTRL", "label": null}], "proj": {"par": 19, "idx": 1}},
+ {"id": 14, "label": "True", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 30, "role": "CTRL", "label": null}], "proj": {"par": 30, "idx": 0}},
+ {"id": 15, "label": "1", "type": null, "kind": "DATA", "edges": [], "proj": null},
+ {"id": 16, "label": "+", "type": null, "kind": "DATA", "edges": [{"idx": 0, "def": 0, "role": "DATA", "label": null}, {"idx": 1, "def": 8, "role": "DATA", "label": null}, {"idx": 2, "def": 15, "role": "DATA", "label": null}], "proj": null},
+ {"id": 17, "label": "5", "type": null, "kind": "DATA", "edges": [], "proj": null},
+ {"id": 18, "label": "==", "type": null, "kind": "DATA", "edges": [{"idx": 0, "def": 0, "role": "DATA", "label": null}, {"idx": 1, "def": 16, "role": "DATA", "label": null}, {"idx": 2, "def": 17, "role": "DATA", "label": null}], "proj": null},
+ {"id": 19, "label": "If", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 5, "role": "CTRL", "label": null}, {"idx": 1, "def": 18, "role": "DATA", "label": null}], "proj": null},
+ {"id": 20, "label": "False", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 30, "role": "CTRL", "label": null}], "proj": {"par": 30, "idx": 1}},
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+ {"id": 26, "label": "φ_arg", "type": null, "kind": "PHI", "edges": [{"idx": 0, "def": 25, "role": "ASSOC", "label": null}, {"idx": 1, "def": 8, "role": "DATA", "label": null}, {"idx": 2, "def": 16, "role": "DATA", "label": null}], "proj": null},
+ {"id": 28, "label": "6", "type": null, "kind": "DATA", "edges": [], "proj": null},
+ {"id": 29, "label": "==", "type": null, "kind": "DATA", "edges": [{"idx": 0, "def": 0, "role": "DATA", "label": null}, {"idx": 1, "def": 16, "role": "DATA", "label": null}, {"idx": 2, "def": 28, "role": "DATA", "label": null}], "proj": null},
+ {"id": 30, "label": "If", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 13, "role": "CTRL", "label": null}, {"idx": 1, "def": 29, "role": "DATA", "label": null}], "proj": null},
+ {"id": 36, "label": "Region", "type": null, "kind": "REGION", "edges": [{"idx": 0, "def": 0, "role": "DATA", "label": null}, {"idx": 1, "def": 25, "role": "CTRL", "label": null}, {"idx": 2, "def": 14, "role": "CTRL", "label": null}], "proj": null},
+ {"id": 37, "label": "φ_arg", "type": null, "kind": "PHI", "edges": [{"idx": 0, "def": 36, "role": "ASSOC", "label": null}, {"idx": 1, "def": 26, "role": "DATA", "label": null}, {"idx": 2, "def": 16, "role": "DATA", "label": null}], "proj": null},
+ {"id": 39, "label": "Return", "type": null, "kind": "CTRL", "edges": [{"idx": 0, "def": 36, "role": "CTRL", "label": null}, {"idx": 1, "def": 37, "role": "DATA", "label": null}], "proj": null}
+ ],
+ "groups": [
+ {"id": 6, "par": 0, "nodes": [5, 6, 7, 8, 10, 11, 12, 13, 14, 18, 19, 20, 29, 30]}
+ ]
+}
diff --git a/docs/chapter08/08-graph3.svg b/docs/chapter08/08-graph3.svg
new file mode 100644
index 00000000..62517032
--- /dev/null
+++ b/docs/chapter08/08-graph3.svg
@@ -0,0 +1,179 @@
+<svg aria-label="Compiler graph" width="955" height="1390" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 955 1390" style="font-family: sans-serif;"><style>
+ html, body { height:100%; margin:0; font-family:sans-serif; }
+ .viewer { height:100%; display:grid; grid-template-rows:auto minmax(0,1fr) auto; }
+ .source { padding:8px; border-bottom:1px solid #ccc; }
+ #program { width:min(600px,80vw); vertical-align:middle; }
+ #status { margin-top:4px; }
+ #graph { min-height:0; overflow:hidden; position:relative; background:#fafbfc; }
+ #elk { width:100%; height:100%; }
+ #graph svg { display:block; }
+ .tools { display:flex; flex-wrap:wrap; align-items:center; gap:14px; margin-top:8px; font-size:12px; }
+ .hint { color:#616c78; }
+ .ctrl { color:#b63838; } .mem { color:#2867b2; } .data { color:#536477; }
+ .edge { fill:none; stroke-width:1.5; }
+ .edge.CTRL { stroke-width:2; }
+ .edge.ASSOC { stroke-dasharray:4 4; }
+ .edge.PARSER { stroke-dasharray:5 4; }
+ .parser rect { fill:#f6f0ff; stroke:#7956a5; stroke-width:1.5; stroke-dasharray:5 4; }
+ .edge.selected { stroke-width:3.5; }
+ .edge.bundle { stroke-width:4; }
+ .edge.bundle.selected { stroke-width:6; }
+ .edge-hit { fill:none; stroke:transparent; stroke-width:12; vector-effect:non-scaling-stroke; pointer-events:stroke; cursor:pointer; }
+ .edge-jump { fill:transparent; pointer-events:all; cursor:pointer; }
+ .node { cursor:pointer; }
+ .box { stroke:#758191; stroke-width:1; }
+ .node.held .box { stroke-dasharray:5 3; }
+ .node.near .box { stroke:#c18221; stroke-width:2; }
+ .node.focus .box { stroke:#9c4900; stroke-width:3; }
+ .node.selected .box { stroke:#1569b9; stroke-width:3; }
+ .node.folded .box { stroke-width:4; }
+ .node.folding .box { fill:#f4ccd7; }
+ .fold-tag { font-size:9px; font-weight:700; fill:#963751; }
+ .peep-area { fill:#fff3d9; fill-opacity:.8; stroke:#c18221; stroke-width:2; pointer-events:none; }
+ .node.peep-edit .box { stroke:#9c4900; stroke-width:3; }
+ .node.error .box { stroke:#b42318; stroke-width:4; }
+ #event.error { color:#b42318; font-weight:600; white-space:pre-wrap; overflow-wrap:anywhere; }
+ .peep-ghosts { pointer-events:none; }
+ .region-box { stroke:#9da9b8; stroke-width:1.5; }
+ .fold-btn { cursor:pointer; }
+ .fold-btn rect { fill:white; stroke:#596674; }
+ .fold-btn text { font-size:14px; fill:#152330; }
+ .fold-btn:focus rect { stroke:#1569b9; stroke-width:2; }
+ .shortcut { cursor:pointer; }
+ .shortcut path { fill:none; stroke-width:1.5; }
+ .shortcut rect { fill:#fff8ec; stroke:#b63838; stroke-dasharray:3 2; }
+ .shortcut text { font-size:11px; fill:#783030; }
+ .shortcut.selected rect, .shortcut:focus rect { stroke-width:2.5; }
+ .label { font-size:12px; fill:#152330; font-weight:600; }
+ .node-id { font-size:10px; fill:#596674; font-weight:400; }
+ .type { font-size:11px; fill:#455768; }
+ .port { stroke:#536477; stroke-width:1; }
+ .row { stroke:#b6afcf; stroke-width:1; }
+ .bind { font-size:12px; fill:#152330; }
+ .slot { font-size:10px; fill:#364352; paint-order:stroke; stroke:#fafbfc; stroke-width:3; }
+ #detail { position:absolute; top:8px; right:8px; margin:0; padding:12px; max-width:320px;
+ max-height:45%; overflow:auto; white-space:pre-wrap; overflow-wrap:anywhere;
+ background:#fffffff2; border:1px solid #bac5d0; border-radius:4px; font-size:12px; }
+ .controls { display:flex; flex-wrap:wrap; justify-content:center; align-items:center; gap:6px; padding:6px; }
+ .button { color:white; background:black; font-size:20px; min-width:30px; }
+ .button:disabled { background:grey; }
+ .count { font-size:20px; min-width:35px; text-align:center; }
+ #N { width:6ch; }
+ #scrub { width:clamp(120px,35vw,600px); }
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L137,547" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#11[0] → #6 · CTRL</title></path><path class="edge DATA" id="e11i1" d="M289,499 L289,504 Q289,509 284,509 L225,509 Q217,509 217,517 L217,547" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#11[1] → #10 · DATA</title></path><path class="edge DATA" id="e16i1" d="M289,395 L289,400 Q289,405 284,405 L54,405 Q46,405 46,413 L46,992 Q46,1000 38,1000 L32,1000 Q24,1000 24,992 L24,92 Q24,84 32,84 L559,84 Q567,84 567,92 L567,147.33333333333331" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#16[1] → #8 · DATA</title></path><path class="edge DATA" id="e16i2" d="M597,74 L597,147.33333333333331" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#16[2] → #15 · DATA</title></path><path class="edge DATA" id="e18i1" d="M567,203.33333333333331 L567,238 Q567,246 559,246 L427,246 Q419,246 419,254 L419,561.6666666666666" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#18[1] → #16 · DATA</title></path><path class="edge DATA" id="e18i2" d="M719,216 L719,221 Q719,226 714,226 L457,226 Q449,226 449,234 L449,561.6666666666666" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#18[2] → #17 · DATA</title></path><path class="edge CTRL" id="e19i0" d="M117,647 L117,659 Q117,667 125,667 L331,667 Q339,667 339,675 L339,695" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#19[0] → #5 · CTRL</title></path><path class="edge DATA" id="e19i1" d="M419,617.6666666666666 L419,695" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#19[1] → #18 · DATA</title></path><path class="edge CTRL" id="e25i1" d="M237,647 L237,1028" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#25[1] → #7 · CTRL</title></path><path class="edge CTRL" id="e25i2" d="M319,795 L319,982 Q319,990 311,990 L275,990 Q267,990 267,998 L267,1028" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#25[2] → #12 · CTRL</title></path><path class="edge DATA" id="e26i1" d="M289,395 L289,400 Q289,405 284,405 L54,405 Q46,405 46,413 L46,992 Q46,1000 54,1000 L361,1000 Q369,1000 369,1008 L369,1028" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#26[1] → #8 · DATA</title></path><path class="edge DATA" id="e26i2" d="M567,203.33333333333331 L567,238 Q567,246 575,246 L703,246 Q711,246 711,254 L711,982 Q711,990 703,990 L417,990 Q409,990 409,998 L409,1028" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#26[2] → #16 · DATA</title></path><path class="edge DATA" id="e29i1" d="M567,203.33333333333331 L567,238 Q567,246 575,246 L589,246 Q597,246 597,254 L597,709.6666666666667" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#29[1] → #16 · DATA</title></path><path class="edge DATA" id="e29i2" d="M871,216 L871,228 Q871,236 863,236 L635,236 Q627,236 627,244 L627,709.6666666666667" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#29[2] → #28 · DATA</title></path><path class="edge CTRL" id="e30i0" d="M439,795 L439,843" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#30[0] → #13 · CTRL</title></path><path class="edge DATA" id="e30i1" d="M597,765.6666666666667 L597,797 Q597,805 589,805 L527,805 Q519,805 519,813 L519,843" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#30[1] → #29 · DATA</title></path><path class="edge CTRL" id="e36i1" d="M237,1084 L237,1096 Q237,1104 245,1104 L421,1104 Q429,1104 429,1112 L429,1132" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#36[1] → #25 · CTRL</title></path><path class="edge CTRL" id="e36i2" d="M419,943 L419,992 Q419,1000 427,1000 L451,1000 Q459,1000 459,1008 L459,1132" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#36[2] → #14 · CTRL</title></path><path class="edge DATA" id="e37i1" d="M389,1084 L389,1089 Q389,1094 394,1094 L553,1094 Q561,1094 561,1102 L561,1132" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#37[1] → #26 · DATA</title></path><path class="edge DATA" id="e37i2" d="M567,203.33333333333331 L567,238 Q567,246 575,246 L703,246 Q711,246 711,254 L711,982 Q711,990 703,990 L609,990 Q601,990 601,998 L601,1132" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#37[2] → #16 · DATA</title></path><path class="edge CTRL" id="e39i0" d="M429,1188 L429,1236" stroke="#b63838" marker-start="url(#arrow-CTRL)" style="opacity: 1;"><title>#39[0] → #36 · CTRL</title></path><path class="edge DATA" id="e39i1" d="M581,1188 L581,1193 Q581,1198 576,1198 L477,1198 Q469,1198 469,1206 L469,1236" stroke="#536477" marker-start="url(#arrow-DATA)" style="opacity: 1;"><title>#39[1] → #37 · DATA</title></path></g><g class="edge-hits"/><g class="parser" style="opacity: 1;"/><g class="nodes"><g class="node" id="n1" data-id="1" transform="translate(77,166)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>$ctrl</tspan><tspan class="node-id">  #1/0</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#1 $ctrl
+Projection 0 of #2
+Type not computed
+
+[0] → #2 CTRL</title></g><g class="node" id="n2" data-id="2" transform="translate(77,122)" style="opacity: 1;"><path class="box" d="M0,0H240V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="120" y="18"><tspan>Start</tspan><tspan class="node-id">  #2</tspan></text><text class="type" text-anchor="middle" y="35" x="120"/><title>#2 Start
+Type not computed
+
+</title></g><g class="node" id="n3" data-id="3" transform="translate(441.5,1340)" style="opacity: 1;"><path class="box" d="M0,0H72V26H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="36" y="17"><tspan>Stop</tspan><tspan class="node-id">  #3</tspan></text><text class="type" text-anchor="middle" y="35" x="36"/><title>#3 Stop
+Type not computed
+
+[0] → #39 CTRL</title><circle class="port" cx="36" cy="0" r="3" fill="#536477"/><text class="slot" x="36" y="-7" text-anchor="middle">0</text></g><g class="node" id="n4" data-id="4" transform="translate(197,166)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>arg</tspan><tspan class="node-id">  #4/1</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#4 arg
+Projection 1 of #2
+Type not computed
+
+[0] → #2 DATA</title></g><g class="node" id="n5" data-id="5" transform="translate(57,597)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>True</tspan><tspan class="node-id">  #5/0</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#5 True
+Projection 0 of #11
+Type not computed
+
+[0] → #11 CTRL</title></g><g class="node" id="n6" data-id="6" transform="translate(77,345)" style="opacity: 1;"><path class="box" d="M20,0H100Q120,0 120,20V24Q120,44 100,44H20Q0,44 0,24V20Q0,0 20,0Z" fill="#ffe0ab"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>Loop</tspan><tspan class="node-id">  #6</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#6 Loop
+Type not computed
+
+[0] → — DATA
+[1] → #1 CTRL
+[2] → #20 CTRL</title><circle class="port" cx="30" cy="-3" r="3" fill="white"/><circle class="port" cx="60" cy="-3" r="3" fill="#536477"/><circle class="port" cx="90" cy="-3" r="3" fill="#536477"/><text class="slot" x="30" y="-10" text-anchor="middle">0</text><text class="slot" x="60" y="-10" text-anchor="middle">1</text><text class="slot" x="90" y="-10" text-anchor="middle">2</text></g><g class="node" id="n7" data-id="7" transform="translate(177,597)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>False</tspan><tspan class="node-id">  #7/1</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#7 False
+Projection 1 of #11
+Type not computed
+
+[0] → #11 CTRL</title></g><g class="node" id="n8" data-id="8" transform="translate(229,345)" style="opacity: 1;"><path class="box" d="M12,0H108L120,22L108,44H12L0,22Z" fill="#f5e4fa"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>φ_arg</tspan><tspan class="node-id">  #8</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#8 φ_arg
+Type not computed
+
+[0] → #6 ASSOC
+[1] → #4 DATA
+[2] → #16 DATA</title><circle class="port" cx="-3" cy="22" r="3" fill="#536477"/><circle class="port" cx="40" cy="-3" r="3" fill="#536477"/><circle class="port" cx="80" cy="-3" r="3" fill="#536477"/><path class="reg" fill="none" stroke="#b63838" d="M-3,22H-18m4,-3l-4,3l4,3"><title>[0] → #6</title></path><text class="slot" x="-10" y="15" text-anchor="middle">0</text><text class="slot" x="40" y="-10" text-anchor="middle">1</text><text class="slot" x="80" y="-10" text-anchor="middle">2</text></g><g class="node" id="n9" data-id="9" transform="translate(355,166)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>10</tspan><tspan class="node-id">  #9</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#9 10
+Type not computed
+
+</title></g><g class="node" id="n10" data-id="10" transform="translate(229,449)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>&lt;</tspan><tspan class="node-id">  #10</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#10 &lt;
+Type not computed
+
+[0] → — DATA
+[1] → #8 DATA
+[2] → #9 DATA</title><circle class="port" cx="30" cy="-3" r="3" fill="white"/><circle class="port" cx="60" cy="-3" r="3" fill="#536477"/><circle class="port" cx="90" cy="-3" r="3" fill="#536477"/><text class="slot" x="30" y="-10" text-anchor="middle">0</text><text class="slot" x="60" y="-10" text-anchor="middle">1</text><text class="slot" x="90" y="-10" text-anchor="middle">2</text></g><g class="node" id="n11" data-id="11" transform="translate(57,553)" style="opacity: 1;"><path class="box" d="M0,0H240V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="120" y="18"><tspan>If</tspan><tspan class="node-id">  #11</tspan></text><text class="type" text-anchor="middle" y="35" x="120"/><title>#11 If
+Type not computed
+
+[0] → #6 CTRL
+[1] → #10 DATA</title><circle class="port" cx="80" cy="-3" r="3" fill="#536477"/><circle class="port" cx="160" cy="-3" r="3" fill="#536477"/><text class="slot" x="80" y="-10" text-anchor="middle">0</text><text class="slot" x="160" y="-10" text-anchor="middle">1</text></g><g class="node" id="n12" data-id="12" transform="translate(259,745)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>True</tspan><tspan class="node-id">  #12/0</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#12 True
+Projection 0 of #19
+Type not computed
+
+[0] → #19 CTRL</title></g><g class="node" id="n13" data-id="13" transform="translate(379,745)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>False</tspan><tspan class="node-id">  #13/1</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#13 False
+Projection 1 of #19
+Type not computed
+
+[0] → #19 CTRL</title></g><g class="node" id="n14" data-id="14" transform="translate(359,893)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>True</tspan><tspan class="node-id">  #14/0</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#14 True
+Projection 0 of #30
+Type not computed
+
+[0] → #30 CTRL</title></g><g class="node" id="n15" data-id="15" transform="translate(537,24)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>1</tspan><tspan class="node-id">  #15</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#15 1
+Type not computed
+
+</title></g><g class="node" id="n16" data-id="16" transform="translate(507,153.33333333333331)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>+</tspan><tspan class="node-id">  #16</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#16 +
+Type not computed
+
+[0] → — DATA
+[1] → #8 DATA
+[2] → #15 DATA</title><circle class="port" cx="30" cy="-3" r="3" fill="white"/><circle class="port" cx="60" cy="-3" r="3" fill="#536477"/><circle class="port" cx="90" cy="-3" r="3" fill="#536477"/><text class="slot" x="30" y="-10" text-anchor="middle">0</text><text class="slot" x="60" y="-10" text-anchor="middle">1</text><text class="slot" x="90" y="-10" text-anchor="middle">2</text></g><g class="node" id="n17" data-id="17" transform="translate(659,166)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>5</tspan><tspan class="node-id">  #17</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#17 5
+Type not computed
+
+</title></g><g class="node" id="n18" data-id="18" transform="translate(359,567.6666666666666)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>==</tspan><tspan class="node-id">  #18</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#18 ==
+Type not computed
+
+[0] → — DATA
+[1] → #16 DATA
+[2] → #17 DATA</title><circle class="port" cx="30" cy="-3" r="3" fill="white"/><circle class="port" cx="60" cy="-3" r="3" fill="#536477"/><circle class="port" cx="90" cy="-3" r="3" fill="#536477"/><text class="slot" x="30" y="-10" text-anchor="middle">0</text><text class="slot" x="60" y="-10" text-anchor="middle">1</text><text class="slot" x="90" y="-10" text-anchor="middle">2</text></g><g class="node" id="n19" data-id="19" transform="translate(259,701)" style="opacity: 1;"><path class="box" d="M0,0H240V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="120" y="18"><tspan>If</tspan><tspan class="node-id">  #19</tspan></text><text class="type" text-anchor="middle" y="35" x="120"/><title>#19 If
+Type not computed
+
+[0] → #5 CTRL
+[1] → #18 DATA</title><circle class="port" cx="80" cy="-3" r="3" fill="#536477"/><circle class="port" cx="160" cy="-3" r="3" fill="#536477"/><text class="slot" x="80" y="-10" text-anchor="middle">0</text><text class="slot" x="160" y="-10" text-anchor="middle">1</text></g><g class="node" id="n20" data-id="20" transform="translate(479,893)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>False</tspan><tspan class="node-id">  #20/1</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#20 False
+Projection 1 of #30
+Type not computed
+
+[0] → #30 CTRL</title></g><g class="node" id="n25" data-id="25" transform="translate(177,1034)" style="opacity: 1;"><path class="box" d="M12,0H108L120,44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>Region</tspan><tspan class="node-id">  #25</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#25 Region
+Type not computed
+
+[0] → — DATA
+[1] → #7 CTRL
+[2] → #12 CTRL</title><circle class="port" cx="30" cy="-3" r="3" fill="white"/><circle class="port" cx="60" cy="-3" r="3" fill="#536477"/><circle class="port" cx="90" cy="-3" r="3" fill="#536477"/><text class="slot" x="30" y="-10" text-anchor="middle">0</text><text class="slot" x="60" y="-10" text-anchor="middle">1</text><text class="slot" x="90" y="-10" text-anchor="middle">2</text></g><g class="node" id="n26" data-id="26" transform="translate(329,1034)" style="opacity: 1;"><path class="box" d="M12,0H108L120,22L108,44H12L0,22Z" fill="#f5e4fa"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>φ_arg</tspan><tspan class="node-id">  #26</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#26 φ_arg
+Type not computed
+
+[0] → #25 ASSOC
+[1] → #8 DATA
+[2] → #16 DATA</title><circle class="port" cx="-3" cy="22" r="3" fill="#536477"/><circle class="port" cx="40" cy="-3" r="3" fill="#536477"/><circle class="port" cx="80" cy="-3" r="3" fill="#536477"/><path class="reg" fill="none" stroke="#b63838" d="M-3,22H-18m4,-3l-4,3l4,3"><title>[0] → #25</title></path><text class="slot" x="-10" y="15" text-anchor="middle">0</text><text class="slot" x="40" y="-10" text-anchor="middle">1</text><text class="slot" x="80" y="-10" text-anchor="middle">2</text></g><g class="node" id="n28" data-id="28" transform="translate(811,166)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>6</tspan><tspan class="node-id">  #28</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#28 6
+Type not computed
+
+</title></g><g class="node" id="n29" data-id="29" transform="translate(537,715.6666666666667)" style="opacity: 1;"><path class="box" d="M14,0H106Q120,0 120,14V30Q120,44 106,44H14Q0,44 0,30V14Q0,0 14,0Z" fill="#edf3f7"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>==</tspan><tspan class="node-id">  #29</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#29 ==
+Type not computed
+
+[0] → — DATA
+[1] → #16 DATA
+[2] → #28 DATA</title><circle class="port" cx="30" cy="-3" r="3" fill="white"/><circle class="port" cx="60" cy="-3" r="3" fill="#536477"/><circle class="port" cx="90" cy="-3" r="3" fill="#536477"/><text class="slot" x="30" y="-10" text-anchor="middle">0</text><text class="slot" x="60" y="-10" text-anchor="middle">1</text><text class="slot" x="90" y="-10" text-anchor="middle">2</text></g><g class="node" id="n30" data-id="30" transform="translate(359,849)" style="opacity: 1;"><path class="box" d="M0,0H240V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="120" y="18"><tspan>If</tspan><tspan class="node-id">  #30</tspan></text><text class="type" text-anchor="middle" y="35" x="120"/><title>#30 If
+Type not computed
+
+[0] → #13 CTRL
+[1] → #29 DATA</title><circle class="port" cx="80" cy="-3" r="3" fill="#536477"/><circle class="port" cx="160" cy="-3" r="3" fill="#536477"/><text class="slot" x="80" y="-10" text-anchor="middle">0</text><text class="slot" x="160" y="-10" text-anchor="middle">1</text></g><g class="node" id="n36" data-id="36" transform="translate(369,1138)" style="opacity: 1;"><path class="box" d="M12,0H108L120,44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>Region</tspan><tspan class="node-id">  #36</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#36 Region
+Type not computed
+
+[0] → — DATA
+[1] → #25 CTRL
+[2] → #14 CTRL</title><circle class="port" cx="30" cy="-3" r="3" fill="white"/><circle class="port" cx="60" cy="-3" r="3" fill="#536477"/><circle class="port" cx="90" cy="-3" r="3" fill="#536477"/><text class="slot" x="30" y="-10" text-anchor="middle">0</text><text class="slot" x="60" y="-10" text-anchor="middle">1</text><text class="slot" x="90" y="-10" text-anchor="middle">2</text></g><g class="node" id="n37" data-id="37" transform="translate(521,1138)" style="opacity: 1;"><path class="box" d="M12,0H108L120,22L108,44H12L0,22Z" fill="#f5e4fa"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>φ_arg</tspan><tspan class="node-id">  #37</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#37 φ_arg
+Type not computed
+
+[0] → #36 ASSOC
+[1] → #26 DATA
+[2] → #16 DATA</title><circle class="port" cx="-3" cy="22" r="3" fill="#536477"/><circle class="port" cx="40" cy="-3" r="3" fill="#536477"/><circle class="port" cx="80" cy="-3" r="3" fill="#536477"/><path class="reg" fill="none" stroke="#b63838" d="M-3,22H-18m4,-3l-4,3l4,3"><title>[0] → #36</title></path><text class="slot" x="-10" y="15" text-anchor="middle">0</text><text class="slot" x="40" y="-10" text-anchor="middle">1</text><text class="slot" x="80" y="-10" text-anchor="middle">2</text></g><g class="node" id="n39" data-id="39" transform="translate(389,1242)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>Return</tspan><tspan class="node-id">  #39</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#39 Return
+Type not computed
+
+[0] → #36 CTRL
+[1] → #37 DATA</title><circle class="port" cx="40" cy="-3" r="3" fill="#536477"/><circle class="port" cx="80" cy="-3" r="3" fill="#536477"/><text class="slot" x="40" y="-10" text-anchor="middle">0</text><text class="slot" x="80" y="-10" text-anchor="middle">1</text></g></g><g class="region-heads" style="opacity: 1;"><g class="region-head" transform="translate(34,269)"><text class="label" x="26" y="17"><tspan>Loop</tspan><tspan class="node-id">  #6</tspan></text><title>Loop · 14 nodes</title><g class="fold-btn" role="button" tabindex="0" transform="translate(4,4)" aria-label="Fold region #6"><rect width="16" height="16" rx="2"/><text x="8" y="12" text-anchor="middle">−</text><title>Fold region</title></g></g></g><g class="shortcuts" style="opacity: 1;"/><g class="peep-ghosts" pointer-events="none"/></g></svg>
diff --git a/docs/chapter08/Makefile b/docs/chapter08/Makefile
new file mode 100644
index 00000000..6fa0f057
--- /dev/null
+++ b/docs/chapter08/Makefile
@@ -0,0 +1 @@
+include ../../graph/docs.mk
diff --git a/docs/chapter08/README.md b/docs/chapter08/README.md
new file mode 100644
index 00000000..ad01385b
--- /dev/null
+++ b/docs/chapter08/README.md
@@ -0,0 +1,325 @@
+# Chapter 8: Lazy Phis, Break, Continue, and Evaluator
+
+[Previous: Chapter 7](../chapter07/README.md) |
+[Next: Chapter 9](../chapter09/README.md)
+
+# Table of Contents
+
+1. [Lazy Phi Creation](#lazy-phi-creation)
+2. [Continue statement](#continue-statement)
+3. [Break statement](#break-statement)
+4. [Parser Considerations](#parser-considerations)
+5. [Examples](#examples)
+ - [Example 1](#example-1)
+ - [Example 2](#example-2)
+ - [Example 3](#example-3)
+
+6. [Sea of Nodes Graph Evaluator](#sea-of-nodes-graph-evaluator)
+
+You can also read [this chapter](https://github.com/SeaOfNodes/Simple/tree/linear-chapter08) in a linear Git revision history on the [linear](https://github.com/SeaOfNodes/Simple/tree/linear) branch and [compare](https://github.com/SeaOfNodes/Simple/compare/linear-chapter07...linear-chapter08) it to the previous chapter.
+
+
+In this chapter:
+
+* We move from eager to lazy `Phi` creation in loops.
+* We add support for `break` and `continue` statements.
+* We implement a Sea of Nodes Graph Evaluator.
+
+Here is the [complete language grammar](08-grammar.md) for this chapter.
+
+
+## Lazy Phi Creation
+
+In [chapter 7](../chapter07/README.md), we created `PhiNode`s for all variables
+in the loop head eagerly. This approach creates some unnecessary Phis but the
+redundant Phis get cleaned up later.
+
+In this chapter we add support for creating the `PhiNode`s lazily.
+
+The main complication with creating `PhiNode`s lazily is that when we create a
+Phi, it must be created in the innermost loop head scope where it would have
+been created had we done it eagerly. Since scopes get duped in `if` and
+`while` statements, we cannot just create Phis in the current scope.
+
+It turns out that the easiest way to create the `PhiNode`s lazily is to hook
+them up to name lookup. But how do we know that a Phi must be created when we
+access a name? We need a way to flag that a particular name mapping must be
+converted to a `PhiNode` on lookup.
+
+We do this as follows:
+
+* In `ScopeNode.dup()`, if the Scope is being duplicated for a loop head, then
+ instead of setting the name's definition to the original node, we set it to
+ the Scope itself. This acts like a sentinel.
+
+ ```java
+ // For lazy phis on loops we use a sentinel
+ // that will trigger phi creation on update
+ dup.addDef(loop ? this : in(i));
+ ```
+
+* Subsequently, when a lookup accesses a name, we notice that the def is set to
+ the Scope node, and we create a `PhiNode` at this point. The relevant
+ implementation is in `ScopeNode.update()`.
+
+ ```java
+ if( old instanceof ScopeNode loop ) {
+ // Lazy Phi!
+ old = loop.in(idx) instanceof PhiNode phi && loop.ctrl()==phi.region()
+ // Loop already has a real Phi, use it
+ ? loop.in(idx)
+ // Set real Phi in the loop head
+ // The phi takes its one input (no backedge yet) from a recursive
+ // lookup, which might have inserted a Phi in every loop nest.
+ : loop.setDef(idx,new PhiNode(name,loop.ctrl(),loop.update(name,null,nestingLevel),null).peephole());
+ setDef(idx,old);
+ }
+ ```
+
+* When we merge scopes, we ensure lazy `PhiNode` creation at the correct inner
+ scope level by invoking lookup by name instead of directly accessing the
+ defs.
+
+ ```java
+ if( in(i) != that.in(i) ) // No need for redundant Phis
+ // If we are in lazy phi mode we need to do a lookup
+ // by name as it will trigger a phi creation
+ setDef(i, new PhiNode(ns[i], r, this.lookup(ns[i]), that.lookup(ns[i])).peephole());
+ ```
+
+* Finally, in `ScopeNode.endLoop()` we clean up any leftover sentinels, replacing the sentinel with the input from loop head.
+
+ ```java
+ for( int i=1; i<nIns(); i++ ) {
+ if( back.in(i) != this ) {
+ PhiNode phi = (PhiNode)in(i);
+ assert phi.region()==ctrl && phi.in(2)==null;
+ phi.setDef(2,back.in(i));
+ // Do an eager useless-phi removal
+ Node in = phi.peephole();
+ if( in != phi )
+ phi.subsume(in);
+ }
+ if( exit.in(i) == this ) // Replace a lazy-phi on the exit path also
+ exit.setDef(i,in(i));
+ }
+ ```
+
+## `continue` Statement
+
+In Chapter 7, we had a single backedge from the loop's end flowing back to the
+loop head.
+
+With the addition of a `continue` statement, we can have multiple backedges
+flowing back to the loop head.
+
+We have several ways of implementing these backedges.
+
+1. The traditional way would be to let each backedge from `continue` merge into
+ the loop head. Phis would require as many inputs as there are edges. The
+ downside is now our Loops are not simply nested. This makes it difficult to
+ do many kinds of peephole-based loop optimizations, such as "partially
+ rolling" the loop to allow more loop invariants to get hoisted.
+2. An alternative is to collect all `continue`s at a single merge point (`Region`)
+ and then create a single backedge flowing from the continue `Region` to the
+ loop head.
+3. A third approach is to create a stack of continue `Region`s rather than a
+ single continue `Region`. This has the benefit of keeping our Phis simple
+ with just two inputs as they are now, whereas the other approaches require
+ Phis with more than 2 inputs. On the other hand we end up with as many
+ continue `Region`s as there are `continue` statements, and corresponding
+ Phis that are stacked.
+
+In this chapter we adopt option 3 as it is the simplest implementation on top
+of our basic `while` loop architecture.[^1]
+
+The implementation requires some careful handling of scopes. This is because
+we would like to only generate `PhiNode/RegionNode`s for `continues` if necessary.
+
+In our [basic loop architecture](../chapter07/README.md), by the time we get to
+the loop backedge, we have already exited all nested blocks/scopes, we just
+need to stitch together the current scope+ctrl into the Loop scope+ctrl and
+create `PhiNode`s as needed.
+
+A `continue` however, can occur inside nested scopes (such as nested `if`
+statement). Since we want to lazily create the continue `Region`, the first
+time we see a `continue`, we need to dupe the head scope and merge the current
+scope into it to generate a continue Scope and `Region`. Subsequently, when we
+see another `continue`, we need to construct a new `Region` and merge the
+previous continue Scope with the current Scope.
+
+The implementation is a variation of the above.
+
+* The first `continue` triggers a dupe of the current scope; we prune any
+ nested lexical scopes deeper than the head scope, removing any name bindings
+ that were not visible in the head scope. This is essentially ensuring that
+ we "exit" any nested scopes.
+
+ We set the continue scope initially to null.
+
+ ```java
+ // No continues yet
+ _continueScope = null;
+ ```
+ When we parse continue, the first time `_continueScope` is null.
+
+ ```java
+ private Node parseContinue() { return (_continueScope = require(jumpTo( _continueScope ),";")); }
+
+ private ScopeNode jumpTo(ScopeNode toScope) {
+ ScopeNode cur = _scope.dup();
+ ctrl(new ConstantNode(Type.XCONTROL).peephole()); // Kill current scope
+ // Prune nested lexical scopes that have depth > than the loop head
+ // We use _breakScope as a proxy for the loop head scope to obtain the depth
+ while( cur._scopes.size() > _breakScope._scopes.size() )
+ cur.pop();
+ // If this is a continue then first time the target is null
+ // So we just use the pruned current scope as the base for the
+ // continue
+ if (toScope == null)
+ return cur;
+ // toScope is either the break scope, or a scope that was created here
+ assert toScope._scopes.size() <= _breakScope._scopes.size();
+ toScope.mergeScopes(cur);
+ return toScope;
+ }
+ ```
+
+* The continue scope becomes the base scope for the subsequent `continue`
+ statement, thus forming a stack of continue scopes/regions.
+* After the loop is done, if we find that a continue scope was created within
+ the loop, we must merge the current scope into the continue scope, and make
+ the continue scope the active scope.
+
+ ```java
+ // Merge the loop bottom into other continue statements
+ if (_continueScope != null) {
+ _continueScope = jumpTo(_continueScope);
+ _scope.kill();
+ _scope = _continueScope;
+ }
+ ```
+
+## `break` Statement
+
+Implementing `break` is simpler than `continue`, because the exit scope is
+created before we parse the loop body, and this becomes the initial `break`
+scope. When we see `break`, we merge the current scope, after pruning any
+nested lexical scopes, to the current break scope, and the resulting new scope
+becomes the active break scope.
+
+## Parser Considerations
+
+Since a `continue` or `break` targets the immediate surrounding `while` loop,
+we maintain a stack of the `continue` and `break` scopes. This is done by
+saving the previous `continue` or `break` scope before parsing a `while` loop
+and restoring afterward.
+
+## Examples
+
+### Example 1
+
+```java
+while(arg < 10) {
+ arg = arg + 1;
+ if (arg == 5)
+ continue;
+ if (arg == 6)
+ break;
+}
+return arg;
+```
+
+![Graph1](./08-graph1.svg)
+
+
+### Example 2
+
+```java
+while(arg < 10) {
+ arg = arg + 1;
+ if (arg == 5)
+ continue;
+ if (arg == 6)
+ continue;
+}
+return arg;
+```
+
+![Graph1](./08-graph2.svg)
+
+### Example 3
+
+```java
+while(arg < 10) {
+ arg = arg + 1;
+ if (arg == 5)
+ break;
+ if (arg == 6)
+ break;
+}
+return arg;
+```
+
+![Graph1](./08-graph3.svg)
+
+
+## Sea of Nodes Graph Evaluator
+
+The evaluator directly evaluates the given graph by walking forward through the control flow from the program start until it either encounters a Return node or it passes the maximum loop count.
+
+When called, the evaluator sets itself up by first traversing the graph to find the Start node. Then, if a program uses the special `arg` parameter, the passed-in parameter value will be bound to the node that represents it.
+
+With that brief setup done, the control projection from the Start node is traversed and the program can begin "execution".
+
+At this point, control flow is at the first region of the program, but it is treated just the same as any other region. There are two things that must be done at each region. First, resolve all phis to a specific value; and second to determine where control flow will continue to.
+
+It may seem like more than that should be done, but by resolving phi nodes, any logic that is specific to the control flow path for the given region will be resolved. Any other work will eventually be resolved later on as-needed. This is sufficient for the program to run!
+
+Finding the next place control flow will move to after a region is straightforward because any region only has a single control node that uses it. So we search for that node in the Region's users.
+
+Once we have that node, our behavior depends on what type of control flow node we've landed on. There are only 3 options: `RegionNode`, `IfNode`, and `ReturnNode`. If it is another `RegionNode`, we do the same again. If it's a `ReturnNode`, we can resolve the returned expression and return the program's value. Finally, for an `IfNode`, we must first resolve the test expression so that we can choose the true (projection 0) or false (projection 1) branch. Whichever projection from the `IfNode` is chosen, we step through that projection on to the control node (a `RegionNode`) that uses it.
+
+We talk about resolving nodes above, but what does that mean? A node will either have a value (for instance a constant), will already be resolved with the resolved value cached, or it will operate on nodes that it uses, which must be resolved. Once a node's inputs are resolved, its operation may be performed on them. For instance, an `AddNode`'s value will be the sum of its two inputs. Once the value is resolved, the resolved value is returned.
+
+With that, a simple non-looping program can be evaluated.
+
+Looping is almost functional with that, too, with only a couple of small extra details. Whenever control moves through a `LoopNode`, the evaluator checks that it hasn't run out of loop iterations. If it has, a timeout RuntimeException will be thrown.
+
+Finally, while calculating the value of `PhiNode`s in the loop region, we must be careful to compute all of their new values before we update any of their cached values. That's because as a loop iterates, we must ensure that all `PhiNode` values are consistently the value from the same point in time. Once all of the new values are calculated, we can update the cache for all of them at once. To illustrate this, consider the following code:
+
+```java
+int t = 0;
+while(arg < 10) {
+ t = arg;
+ arg = arg + 1;
+}
+return t;
+```
+
+In this code, the two statements within the loop may be evaluated in either
+order by the graph, so we must ensure that the new value `arg` is not cached
+before the value of `t` can be set to the previous value of `arg`.
+
+This approach to evaluation is useful for testing because it allows a program
+to be executed without worrying about instruction selection, register
+allocation or code generation. It executes the graph produced with normal
+peephole optimization. In later chapters, the evaluator can compare graphs
+optimized with different worklist orders to detect inconsistent results. This
+chapter's fuzzer checks generated programs for compiler and evaluator failures.
+
+``` java
+arg=arg+arg;
+arg=arg+arg;
+...
+arg=arg+arg;
+return arg;
+```
+
+On the other hand, this engine is not designed to be particularly fast! Because
+not all expressions are cached, it's possible to construct programs like the
+preceding one which have exponential runtime.
+
+
+[^1]: We also experimented with option 2. For readers who would like to see this
+alternative solution, we provide a separate branch with such an implementation. \ No newline at end of file
generated by cgit v1.2.3 (git 2.25.1) at 2026-10-15 14:11:38 +0000