First pass README updates

1 files changed, 90 insertions, 108 deletions

diff --git a/chapter04/docs/04-post-peephole.svg b/chapter04/docs/04-post-peephole.svg
index 550c16ef..530155dd 100644
--- a/chapter04/docs/04-post-peephole.svg
+++ b/chapter04/docs/04-post-peephole.svg
@@ -1,108 +1,90 @@
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+    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; }
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+    .edge-jump { fill:transparent; pointer-events:all; cursor:pointer; }
+    .node { cursor:pointer; }
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+    .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; }
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+    #detail { position:absolute; top:8px; right:8px; margin:0; padding:12px; max-width:320px;
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+    .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; }
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+    #scrub { width:clamp(120px,35vw,600px); }
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+Type not computed
+
+[0] → —  ASSOC  0: $ctrl
+[1] → #5  ASSOC  0: arg</title><line class="row" x1="0" x2="120" y1="30" y2="30"/><line class="row" x1="63" x2="63" y1="0" y2="30"/><text class="bind" x="31.5" y="20" text-anchor="middle">0: $ctrl</text><text class="bind" x="91.5" y="20" text-anchor="middle">0: arg</text><circle class="port" cx="31.5" cy="0" r="3" fill="white"/><circle class="port" cx="91.5" cy="0" r="3" fill="#536477"/><text class="slot" x="31.5" y="-7" text-anchor="middle">0</text><text class="slot" x="91.5" y="-7" text-anchor="middle">1</text></g><g class="node" id="n2" data-id="2" transform="translate(24,24)" style="opacity: 1;"><path class="box" d="M0,0H240V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="120" y="18"><tspan>Start</tspan><tspan class="node-id">  #2</tspan></text><text class="type" text-anchor="middle" y="35" x="120"/><title>#2 Start
+Type not computed
+
+</title></g><g class="node" id="n4" data-id="4" transform="translate(24,68)" style="opacity: 1;"><path class="box" d="M0,0H120V44H0Z" fill="#fff1c4"/><text class="label" text-anchor="middle" x="60" y="18"><tspan>$ctrl</tspan><tspan class="node-id">  #4/0</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#4 $ctrl
+Projection 0 of #2
+Type not computed
+
+[0] → #2  CTRL</title></g><g class="node" id="n5" data-id="5" transform="translate(144,68)" 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">  #5/1</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#5 arg
+Projection 1 of #2
+Type not computed
+
+[0] → #2  DATA</title></g><g class="node" id="n10" data-id="10" transform="translate(302,68)" 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>#3</tspan><tspan class="node-id">  #10</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#10 #3
+Type not computed
+
+</title></g><g class="node" id="n11" data-id="11" transform="translate(144,172)" 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">  #11</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#11 +
+Type not computed
+
+[0] → —  DATA
+[1] → #5  DATA
+[2] → #10  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="n12" data-id="12" transform="translate(44,276)" 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">  #12</tspan></text><text class="type" text-anchor="middle" y="35" x="60"/><title>#12 Return
+Type not computed
+
+[0] → #4  CTRL
+[1] → #11  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="shortcuts" style="opacity: 1;"/><g class="peep-ghosts" pointer-events="none"/></g></svg>