// Python implementation architecture
// "A diagram is worth 10,000 words." — russell@unturf.com
digraph python_arch {
    rankdir=TB
    node [shape=box, style=filled, fontname="Helvetica"]
    edge [fontname="Helvetica", fontsize=10]

    subgraph cluster_input {
        label="Input"
        style=dashed
        source [label=".lsp source\nstdlib.lsp" fillcolor="#e8f4fd"]
        repl [label="REPL\ninteractive" fillcolor="#e8f4fd"]
    }

    subgraph cluster_frontend {
        label="Frontend"
        style=rounded
        color="#666666"
        tokenizer [label="Tokenizer\n_tokenize_lines()" fillcolor="#fff3cd"]
        parser [label="Parser\n_read() → Pair AST" fillcolor="#fff3cd"]
        macros [label="Macro Expander\nsyntax-rules\ndefine-macro" fillcolor="#fff3cd"]
    }

    subgraph cluster_eval {
        label="Evaluators (two paths)"
        style=rounded
        color="#666666"

        leval [label="Tree-Walker\nleval()\nTCO via while loop" fillcolor="#d4edda"]
        compiler [label="Bytecode Compiler\n_bc() → CodeObj\n40 opcodes + superinstrs" fillcolor="#cce5ff"]
        vm [label="Stack VM\n_vm_loop()\nexplicit frame stack" fillcolor="#cce5ff"]
        jit_py [label="Python JIT\n(prototype)\nexec() transpile" fillcolor="#f8d7da" style="filled,dashed"]
    }

    subgraph cluster_runtime {
        label="Runtime"
        style=rounded
        color="#666666"
        env [label="Environment\nEnv chain + global shortcut\ninline cache" fillcolor="#e2d5f1"]
        types [label="Types\nSymbol, Pair, Proc\nCompiledProc, FullCont\nMutableString, Fraction" fillcolor="#e2d5f1"]
        gc [label="Memory\nPython GC\n(automatic)" fillcolor="#e2d5f1"]
    }

    subgraph cluster_features {
        label="Features"
        style=rounded
        color="#666666"
        callcc [label="Full Continuations\ncall/cc\nmulti-shot" fillcolor="#ffeaa7"]
        portal [label="Portal\nserialize VM state\nresume on another machine" fillcolor="#ffeaa7"]
        serial [label="Bytecode Serialization\n.lspc files\nJSON format" fillcolor="#ffeaa7"]
    }

    source -> tokenizer
    repl -> tokenizer
    tokenizer -> parser
    parser -> macros
    macros -> leval [label="interpreted"]
    macros -> compiler [label="--fast"]
    compiler -> vm
    vm -> jit_py [label="hot funcs" style=dashed]
    leval -> env
    vm -> env
    env -> types
    types -> gc
    vm -> callcc
    callcc -> portal
    compiler -> serial

    {rank=same; leval; compiler}
    {rank=same; callcc; portal; serial}
}