nx_js_vm.nx

nx_js_compile.nx -- BYTECODE-VM rungs 2+3+4a+4b: the AST->BYTECODE COMPILER + a TAGGED-VALUE stack VM. rung2: walk nx_js_parse's AST once, emit bytecode (number/ident/assign/binary/var/while/if/block). rung3: the VM stack + vars carry the engine's 2-slot [tag,payload] value model (VAL_NUM/STR/BOOL/...). rung4a: logical short-circuit && || + unary ! - + typeof. rung4b (FUNCTIONS + OBJECTS -- the real-bundle rung): function decls/exprs/arrows compile to a FUNCTION TABLE + inline bodies (JMP over); calls run on CALL FRAMES; CLOSURES are arena-allocated env records chained by lexical parent (variables resolve at COMPILE time to depth+slot -- no name lookup at runtime); objects/arrays/member/index reuse the engine's obj_*/arr_*/ev_get_prop model; `this` rides an env-header binding (env-chain walk == the tree-walker's THIS_NS lookup); `new` allocates + binds this + keeps the object unless the ctor returns one; natives dispatch through js_native_apply (the value-based core split out of js_invoke_native); for/do-while/ternary/ break/continue/switch/for-of/for-in/??/compound-assign/destructuring/spread all compile. The VM has an ERROR CHANNEL (BC_ERROR + honest halts) so rc parity with js_run_source is gated. NAMED OPENS (rung-4c/5): template ${} interpolation (no-interp templates work) -- BC_ERROR; VM closures passed to callback natives (forEach/map/setTimeout/then) need the rung-5 VM re-entry (js_call_core expects tree closures; VM closure records carry VMF_MAGIC so the wire can detect); per-iteration for-of capture + for-scope vars are FUNCTION-scoped here (real-JS var semantics; the tree-walker gives for-loops their own child env -- divergence only for post-loop var reads). license_tier: ORIGINAL