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xo-expression2 xo-reader2: local symtab stack in PSM

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This commit is contained in:
Roland Conybeare 2026-01-30 10:26:35 -05:00
commit f5ccd99dd2
8 changed files with 127 additions and 21 deletions
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31
include/xo/reader2/ParserStateMachine.hpp
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@ -6,6 +6,8 @@
#pragma once
#include "ParserResult.hpp"
#include <xo/expression2/DGlobalSymtab.hpp>
#include <xo/expression2/DLocalSymtab.hpp>
#include <xo/expression2/DVariable.hpp>
#include <xo/expression2/StringTable.hpp>
#include <xo/tokenizer2/Token.hpp>
@ -47,6 +49,7 @@ namespace xo {
bool debug_flag() const noexcept { return debug_flag_; }
ParserStack * stack() const noexcept { return stack_; }
obj<AAllocator> expr_alloc() const noexcept { return expr_alloc_; }
DLocalSymtab * local_symtab() const noexcept { return local_symtab_; }
const ParserResult & result() const noexcept { return result_; }
/** true iff state machine is currently idle (at top-level) **/
@ -79,6 +82,15 @@ namespace xo {
**/
const DUniqueString * intern_string(std::string_view str);
/** push nested local symtab while parsing the body of a lambda expression;
* restore previous symtab at the end of lambda-expression definition.
* See @ref pop_local_symtab
**/
void push_local_symtab(DLocalSymtab * symtab);
/** pop nested symbol table from symbol-table stack **/
void pop_local_symtab();
/** add variable to current local environment (innermost lexical scope) **/
void upsert_var(DVariable * var);
@ -219,8 +231,10 @@ namespace xo {
* after encountering a parsing error.
**/
DArena::Checkpoint parser_alloc_ckp_;
/** parser stack. Memory from @ref parser_alloc_ **/
/** parser stack. Memory always from @ref parser_alloc_;
* elements that should survive parsing allocate from
* @ref expr_alloc_, see below.
**/
ParserStack * stack_ = nullptr;
/** Allocator for parsed expressions.
@ -239,6 +253,19 @@ namespace xo {
**/
obj<AAllocator> expr_alloc_;
/** symbol table with local bindings.
* non-null during parsing of lambda expressions.
* Always allocated from @p expr_alloc_.
* Push local symbol table here to remember local params
* during the body of a lambda expression.
**/
DLocalSymtab * local_symtab_ = nullptr;
/** global symbol table.
* Toplevel definitions go here.
**/
DGlobalSymtab * global_symtab_ = nullptr;
/** current output from parser **/
ParserResult result_;