Module vm 

High-performance bytecode VM for v2 Jetro expressions.

Architecture

 String expression
       │  parser::parse()
       ▼
    Expr (AST)
       │  Compiler::compile()
       ▼
    Program              ← flat Arc<[Opcode]>  (cached: compile_cache)
       │  VM::execute()
       ▼
     Val                 ← result              (structural: resolution_cache)

Optimisations over the tree-walker

1. Compile cache — parse + compile once per unique expression string.
2. Val type — Arc-wrapped compound nodes; every clone is O(1).
3. BuiltinMethod enum — O(1) method dispatch (jump-table vs string hash).
4. Pre-compiled sub-programs — lambda/arg bodies compiled to Arc<Program> once at compile time; never re-compiled per call.
5. Resolution cache — structural programs ($.a.b[0]) cache their pointer path after the first traversal; subsequent calls skip traversal.
6. Peephole pass 1 — RootChain — PushRoot + GetField+ fused into a single pointer-resolve opcode.
7. Peephole pass 2 — FilterCount — CallMethod(filter) + CallMethod(len/count) fused; counts matches without materialising the intermediate filtered array.
8. Peephole pass 3 — ConstFold — arithmetic on adjacent integer literals folded at compile time.
9. Stack machine — iterative exec() loop; no per-opcode stack-frame overhead for simple navigation / arithmetic opcodes.

Structs

BindObjSpec

Compiled bind-object destructure spec.

CompSpec

Compiled comprehension spec.

CompiledCall

A compiled method call stored inside Opcode::CallMethod.

Compiler

DictCompSpec

FieldChainData

Per-step inline caches for Opcode::FieldChain. One AtomicU64 slot per key in the chain — same encoding as Program.ics (slot_idx + 1, 0 unset). Lives inside the opcode rather than the top-level side-table because the chain length is known only at compile time of that specific opcode.

PassConfig

High-performance v2 virtual machine.

Program

A compiled, immutable v2 program. Cheap to clone (Arc internals).

VM

Enums

BuiltinMethod

Pre-resolved method identifier — eliminates string comparison at dispatch.

CompiledFSPart

A compiled f-string interpolation part.

CompiledObjEntry

A compiled object field for Opcode::MakeObj.

KvStep

Single step in a pre-resolved KvPath projection.

Opcode

Functions

fresh_ics

Build a fresh IC side-table with one zeroed AtomicU64 per opcode. Kept public so other modules that fabricate Program values (schema specialisation, analysis passes) can populate the field.