digraph Lattice {
    rankdir=TB;
    newrank=true;
    // Preserve the same-rank ordering edges through cluster layout.
    remincross=false;
    nodesep=0.22;
    ranksep=0.65;
    node [shape=ellipse, style=filled, fontname="DejaVu Sans", fontsize=13];
    edge [color="#555555", arrowsize=0.6];

    // These arrows are lattice-order edges, not use/definition edges.
    TOP [label="⊤", fillcolor=black, fontcolor=white];
    BOT [label="⊥", fillcolor=black, fontcolor=white];

    subgraph cluster_control {
        label="Control"; fontname="Arial"; color="#cccccc";
        node [fillcolor="#ffff00"];
        XCTRL [label="⊤:ctrl"];
        CTRL [label="⊥:ctrl"];
        XCTRL -> CTRL;
    }

    subgraph cluster_integer {
        label="Integer ranges (schematic)"; fontname="Arial"; color="#cccccc";
        INT_TOP [label=<<B>⊤</B >:int>, fillcolor=lightblue, shape=oval];
        INT_BOT [label=<<B>⊥</B>:int>, fillcolor=lightblue, shape=oval];

        INT_HI    [label="max < min" , fillcolor=lightblue, shape=oval];
        INT_XBOOL [label="1...0", fillcolor=lightblue, shape=oval];
        INT_CON   [label="constants", fillcolor=lightblue, shape=oval];
        INT_CON0  [label="0", fillcolor=lightblue];
        INT_CON1  [label="1", fillcolor=lightblue];
        INT_BOOL  [label="0...1", fillcolor=lightblue,shape=oval];
        INT_LO    [label="max > min" , fillcolor=lightblue, shape=oval];

        INT_TOP    -> INT_HI;
        INT_HI     -> INT_XBOOL;
        INT_XBOOL  -> INT_CON0;
        INT_XBOOL  -> INT_CON1;
        INT_HI     -> INT_CON;
        INT_CON0   -> INT_BOOL;
        INT_CON1   -> INT_BOOL;
        INT_BOOL   -> INT_LO;
        INT_CON    -> INT_LO;
        INT_LO     -> INT_BOT;

        INT_CON0 -> INT_CON1 -> INT_CON [style=invis];

        {rank=same; INT_CON0; INT_CON1; INT_CON;}
    }

    subgraph cluster_float {
        label="Float"; fontname="Arial"; color="#cccccc";
        FLT_TOP [label=<<B>⊤</B >:flt>, fillcolor=aqua, shape=oval];
        FLT_BOT [label=<<B>⊥</B>:flt>, fillcolor=aqua, shape=oval];

        FLT_CON64  [label="64b consts\n[excludes\n32b consts]" , fillcolor=aqua, shape=oval];
        FLT_CON32  [label="32b consts", fillcolor=aqua, shape=oval];
        FLT_CONPI  [label="3.14159...", fillcolor=aqua, shape=oval];
        FLT_X32    [label="~f32", fillcolor=aqua];
        FLT_CON0   [label="0."  , fillcolor=aqua];
        FLT_32     [label="f32" , fillcolor=aqua];

        FLT_TOP   -> FLT_CON64
        FLT_TOP   -> FLT_CONPI
        FLT_CON64 -> FLT_BOT
        FLT_CONPI -> FLT_BOT

        FLT_TOP   -> FLT_X32;
        FLT_X32   -> FLT_CON0;
        FLT_X32   -> FLT_CON32;
        FLT_CON0  -> FLT_32;
        FLT_CON32 -> FLT_32;
        FLT_32    -> FLT_BOT

        FLT_CON0 -> FLT_CON32 -> FLT_CONPI -> FLT_CON64 [style=invis];


        {rank=same; FLT_CON0; FLT_CON32; FLT_CONPI; FLT_CON64;}
    }

    subgraph cluster_pointer {
        label="Pointer = nullability × struct type";
        fontname="Arial"; color="#cccccc";
        node [fillcolor="#008000", fontcolor=white];
        PTR_TOP [label="⊤:ptr\n[*⊤:struct]"];
        PTR_BOT [label="⊥:ptr\n[*⊥:struct?]"];
        PTR_NULL [label="null"];
        PTR_ANY [label="*⊥:struct\n[ptr any struct]"];
        PTR_PERSON [label="*Person"];
        PTR_S1 [label="*s1"];
        PTR_MORE [label="*s2, …"];
        PTR_PERSON_NIL [label="*Person?"];
        PTR_S1_NIL [label="*s1?"];
        PTR_MORE_NIL [label="*s2?, …"];
        {rank=same; PTR_PERSON; PTR_S1; PTR_MORE; PTR_NULL;}
        {rank=same; PTR_ANY; PTR_PERSON_NIL; PTR_S1_NIL; PTR_MORE_NIL;}
        PTR_PERSON -> PTR_S1 -> PTR_MORE -> PTR_NULL [style=invis];
        PTR_ANY -> PTR_PERSON_NIL -> PTR_S1_NIL -> PTR_MORE_NIL [style=invis];
        PTR_TOP -> {PTR_PERSON PTR_S1 PTR_MORE PTR_NULL};
        {PTR_PERSON PTR_S1 PTR_MORE} -> PTR_ANY;
        PTR_PERSON -> PTR_PERSON_NIL;
        PTR_S1 -> PTR_S1_NIL;
        PTR_MORE -> PTR_MORE_NIL;
        PTR_NULL -> {PTR_PERSON_NIL PTR_S1_NIL PTR_MORE_NIL};
        {PTR_ANY PTR_PERSON_NIL PTR_S1_NIL PTR_MORE_NIL} -> PTR_BOT;
    }

    subgraph cluster_struct {
        label="Struct\nnamed collection of named scalar types";
        fontname="Arial"; color="#cccccc";
        node [fillcolor="#90ee90"];
        STRUCT_TOP [label="⊤:struct\n[struct top]"];
        STRUCT_BOT [label="⊥:struct\n[struct bottom]"];
        STRUCT_PERSON [label="Person\nage: int", shape=box];
        STRUCT_S1 [label="s1\nx: int", shape=box];
        STRUCT_S2 [label="s2\nx: int, y: *s1", shape=box];
        STRUCT_MORE [label="…", shape=box];
        {rank=same; STRUCT_PERSON; STRUCT_S1; STRUCT_S2; STRUCT_MORE;}
        STRUCT_PERSON -> STRUCT_S1 -> STRUCT_S2 -> STRUCT_MORE [style=invis];
        STRUCT_TOP -> {STRUCT_PERSON STRUCT_S1 STRUCT_S2 STRUCT_MORE};
        {STRUCT_PERSON STRUCT_S1 STRUCT_S2 STRUCT_MORE} -> STRUCT_BOT;
    }

    subgraph cluster_memory {
        label="Memory\nprecise alias slices"; fontname="Arial"; color="#cccccc";
        node [fillcolor="#00008b", fontcolor=white];
        MEM_TOP [label="⊤:mem"];
        MEM_BOT [label="⊥:mem"];
        MEM_ALIAS2 [label="MEM#2"];
        MEM_ALIAS3 [label="MEM#3"];
        MEM_MORE [label="…"];
        {rank=same; MEM_ALIAS2; MEM_ALIAS3; MEM_MORE;}
        MEM_ALIAS2 -> MEM_ALIAS3 -> MEM_MORE [style=invis];
        MEM_TOP -> {MEM_ALIAS2 MEM_ALIAS3 MEM_MORE};
        {MEM_ALIAS2 MEM_ALIAS3 MEM_MORE} -> MEM_BOT;
    }

    subgraph cluster_tuple {
        label="Tuple\ncollection of types";
        fontname="Arial"; color="#cccccc";
        node [fillcolor="#ffc0cb"];
        TUPLE_TOP [label="⊤:tuple"];
        TUPLE_BOT [label="⊥:tuple"];
        // Each black element stands for a recursively nested type lattice.
        TUPLE1 [shape=plain, label=<
            <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
                <TR><TD BGCOLOR="#ffc0cb">tuple</TD></TR>
                <TR><TD BGCOLOR="black"><FONT COLOR="white">type</FONT></TD></TR>
            </TABLE>
        >];
        TUPLE2 [shape=plain, label=<
            <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
                <TR><TD BGCOLOR="#ffc0cb">tuple</TD></TR>
                <TR><TD BGCOLOR="black"><FONT COLOR="white">type</FONT></TD></TR>
                <TR><TD BGCOLOR="black"><FONT COLOR="white">type</FONT></TD></TR>
            </TABLE>
        >];
        TUPLEN [shape=plain, label=<
            <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
                <TR><TD BGCOLOR="#ffc0cb">tuple</TD></TR>
                <TR><TD BGCOLOR="black"><FONT COLOR="white">type</FONT></TD></TR>
                <TR><TD BGCOLOR="black"><FONT COLOR="white">…</FONT></TD></TR>
                <TR><TD BGCOLOR="black"><FONT COLOR="white">type</FONT></TD></TR>
            </TABLE>
        >];
        {rank=same; TUPLE1; TUPLE2; TUPLEN;}
        TUPLE1 -> TUPLE2 -> TUPLEN [style=invis];
        TUPLE_TOP -> {TUPLE1 TUPLE2 TUPLEN};
        {TUPLE1 TUPLE2 TUPLEN} -> TUPLE_BOT;
    }

    TOP -> {XCTRL INT_TOP FLT_TOP PTR_TOP STRUCT_TOP MEM_TOP TUPLE_TOP};
    {CTRL INT_BOT FLT_BOT PTR_BOT STRUCT_BOT MEM_BOT TUPLE_BOT} -> BOT;
    {rank=same; XCTRL; INT_TOP; FLT_TOP; PTR_TOP; STRUCT_TOP; MEM_TOP; TUPLE_TOP;}
    {rank=same; CTRL; INT_BOT; FLT_BOT; PTR_BOT; STRUCT_BOT; MEM_BOT; TUPLE_BOT;}
    XCTRL -> INT_TOP -> FLT_TOP -> PTR_TOP -> STRUCT_TOP -> MEM_TOP -> TUPLE_TOP [style=invis];
}