Robert Allan JamesandClaude Sonnet 5
1aca77d55c
input_buffer/input_length/input_pos (include/vm.h:415-417) turned out to be plain per-VM array/scalar fields, not host pointers -- unlike almost every other input-adjacent gap in this suite. vm_parse_word (src/vm.c: 137-160) is a pure whitespace-delimited scan over them, now modelled as forth_parse_word in StarForth_Base.thy (is_ws + dropWhile/takeWhile, faithful to the C's skip-then-copy-with-truncation loop, including that input_pos only advances past a truncated token by what was actually copied, matching the C's `len < max_len - 1` bound exactly). dict_insert_entry (added last session) now takes the entry's name as a parameter instead of hardcoding the empty string. forth_constant_full composes forth_parse_word with dict_insert_entry end-to-end as a worked example: CONSTANT's real order (stack-underflow guard -> pop value -> parse name -> vm_create_word) is modelled in full up to the data-field write, which remains the one still-open gap. The other four entry-half definitions (:/CREATE/VARIABLE/DEFER) take the parsed name as a caller parameter for now rather than repeating the same composition four more times in one pass. Full suite (54 theories) verifies green. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
98 lines
5.5 KiB
Plaintext
98 lines
5.5 KiB
Plaintext
theory StarForth_Defer_Words
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imports StarForth_Base StarForth_Defining_Words
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begin
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(* =========================================================================
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Mirrors: src/word_source/defer_words.c
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Registers: DEFER IS DEFER@
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── Duplicate-registration finding, same class as `[`/`]`/STATE ─────────
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`word_registry.c` registers `defining_words.c`'s DEFER/IS/DEFER@ at
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Module 17 (line 126) and THIS file's DEFER/IS/DEFER@ at Module 27
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(line 137) -- unconditionally, with no `#ifdef __STARKERNEL__` guarding
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either call. Despite CLAUDE.md categorising `defer_words.c` as a
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"kernel-side-only addition," the hosted `Makefile`'s `SRC` is a bare
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`wildcard src/word_source/*.c` (line 443) with no exclusion for this
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file, and `defer_words.c` itself has no `#ifndef __STARKERNEL__` guard
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the way `lifecycle_words_hosted.c` does -- so it compiles and registers
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in BOTH builds. Registered later, this file's DEFER/IS/DEFER@ SHADOW
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`defining_words.c`'s and are the only reachable versions in either
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build. **This corrects StarForth_Defining_Words.thy's
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`defer_not_modelled`/`is_not_modelled`/`defer_fetch_not_modelled`
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sentinels: those describe dead, shadowed code, not the live
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implementation.** (Those sentinels are still accurate as descriptions
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of what that dead code WOULD do, and the underlying model gaps this
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file hits below are the same ones anyway, so nothing there needs to be
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retracted -- just understood as describing unreachable code.)
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── Why this file isn't more tractable despite being the live version ──
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Every one of DEFER/IS/DEFER@'s real effects still hits the same three
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gaps StarForth_Defining_Words.thy's file header names: (a) dictionary-
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entry creation (`vm_create_word`, used by DEFER), (b) data-field
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addressing (`vm_dictionary_get_data_field` -- DEFER's initial zero-set,
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IS's xt store, DEFER@'s xt fetch, and `defer_runtime`'s own read all
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depend on it), (c) mutable per-entry dispatch (`defer_runtime` reads a
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`DictEntry*` out of the DF cell and calls through it -- `word_table` is
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a fixed global in this suite's model, see StarForth_Base.thy). IS and
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DEFER@ additionally depend on `vm_find_word` (the FIND-family name-
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resolution gap) and a raw `de->func != defer_runtime` function-pointer
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identity comparison, itself unmodellable since `word_table` doesn't
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expose per-entry function identity as a queryable value in this model.
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── Scope ─────────────────────────────────────────────────────────────
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Only IS's stack-underflow guard is modelled (the one real vm_state
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condition that doesn't depend on any of the above). Everything else in
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all three words is not modelled.
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======================================================================== *)
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(* ── IS ( xt -- ) : underflow guard only ──────────────────────────────── *)
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(* C: `if (vm->dsp < 0) { ...; vm->error = 1; return; }` before popping xt
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-- i.e. needs at least one element. Everything after the pop (name
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parse, FIND, defer_runtime identity check, DF store) is unmodelled. *)
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definition forth_is_guard :: "vm_state \<Rightarrow> vm_state" where
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"forth_is_guard vm =
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(if data_stack vm = [] then set_error vm else vm)"
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lemma is_underflow:
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assumes "data_stack vm = []"
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shows "vm_error (forth_is_guard vm)"
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by (simp add: forth_is_guard_def set_error_def assms)
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lemma is_guard_rest_not_modelled: True
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\<comment> \<open>Beyond the underflow guard: name parse (unmodelled TIB dependency),
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vm_find_word (FIND-family gap), the `func != defer_runtime` identity
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check (unmodellable -- word_table has no per-entry function-identity
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query in this model), and the DF store (gap b). See file header.\<close>
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by simp
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(* ── DEFER: entry-creation half, gap (a) PARTIALLY CLOSED 2026-08-14 ─────
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`word_defer` (src/word_source/defer_words.c:73-101) calls
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`vm_create_word(vm, name, len, defer_runtime)` with no extra flags set
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afterward -- same shape as StarForth_Defining_Words.thy's CREATE/
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VARIABLE/CONSTANT, reusing `dict_insert_entry 0` directly. NOT modelled:
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the name parse (TIB gap), and the DF zero-init that follows (gap b). *)
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definition forth_defer_entry_half :: "string \<Rightarrow> bool \<Rightarrow> vm_state \<Rightarrow> vm_state" where
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"forth_defer_entry_half name pinned_conflict vm = dict_insert_entry name 0 pinned_conflict vm"
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lemma defer_entry_half_populates_dictionary:
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assumes "\<not> pinned_conflict"
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shows "\<exists>e. dictionary (forth_defer_entry_half name pinned_conflict vm) (word_id_next vm) = Some e
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\<and> de_name e = name \<and> de_flags e = 0"
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using assms by (simp add: forth_defer_entry_half_def dict_insert_entry_def Let_def)
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lemma defer_entry_half_pinned_conflict_errors:
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assumes "pinned_conflict"
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shows "vm_error (forth_defer_entry_half name pinned_conflict vm)"
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using assms by (simp add: forth_defer_entry_half_def dict_insert_entry_def set_error_def)
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lemma defer_not_modelled: True \<comment> \<open>DEFER beyond the entry-creation half: name parse (TIB gap) + DF zero-init (gap b). See forth_defer_entry_half above for what IS now modelled.\<close>
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by simp
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lemma defer_runtime_not_modelled: True \<comment> \<open>defer_runtime: DF read (gap b) + call-through (gap c).\<close>
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by simp
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lemma defer_fetch_not_modelled: True \<comment> \<open>DEFER@: FIND (name-resolution gap) + DF read (gap b).\<close>
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by simp
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end
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