150 lines
4.6 KiB
C++
150 lines
4.6 KiB
C++
/** @file DParenSsm.hpp
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*
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* @author Roland Conybeare, Feb 2026
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**/
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#pragma once
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#include "DSyntaxStateMachine.hpp"
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#include "syntaxstatetype.hpp"
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#include <xo/facet/obj.hpp>
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#include <string_view>
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namespace xo {
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namespace scm {
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/**
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* @pre
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*
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* ( x * x )
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* ^ ^ ^ ^
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* | | | (done)
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* | | |
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* | | lparen_2
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* | lparen_1:expect expr
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* lparen_0
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*
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* lparen_0 --on_leftparen_token()--> lparen_1
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* lparen_1 --on_parsed_expression()--> lparen_2
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* lparen_2 --on_rightparen_token()--> (done)
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*
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* @endpre
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**/
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enum class parenexprstatetype {
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invalid = -1,
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lparen_0,
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lparen_1,
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lparen_2,
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N,
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};
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extern const char * parenexprstatetype_descr(parenexprstatetype x);
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std::ostream &
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operator<<(std::ostream & os, parenexprstatetype x);
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class DParenSsm : public DSyntaxStateMachine<DParenSsm> {
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public:
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using Super = DSyntaxStateMachine<DParenSsm>;
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using TypeDescr = xo::reflect::TypeDescr;
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using AAllocator = xo::mm::AAllocator;
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using DArena = xo::mm::DArena;
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using ppindentinfo = xo::print::ppindentinfo;
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public:
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/** @defgroup scm-parenssm-ctors **/
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///@{
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DParenSsm();
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/** create instance using memory from @p parser_mm
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**/
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static DParenSsm * _make(DArena & parser_mm);
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/** create fop pointing with new DParenSsm using memory from @p parser_mm **/
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static obj<ASyntaxStateMachine,DParenSsm> make(DArena & parser_mm);
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/** push DParenSsm instance onto @p p_psm stack **/
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static void start(ParserStateMachine * p_psm);
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///@}
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/** @defgroup scm-parenssm-access-methods **/
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///@{
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/** identify this nested state machine **/
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static const char * ssm_classname() { return "DParenSsm"; }
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/** internal state **/
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parenexprstatetype parenstate() const noexcept { return parenstate_; }
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///@}
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/** @defgroup scm-parenssm-admin-methods admin methods **/
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///@{
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/** update ssm state for incoming leftparen token @p tk,
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* with overall parser state in @p p_psm
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**/
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void on_leftparen_token(const Token & tk,
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ParserStateMachine * p_psm);
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/** update ssm state for incoming rightparen token @p tk
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* with overall parser state in @p p_psm
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**/
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void on_rightparen_token(const Token & tk,
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ParserStateMachine * p_psm);
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///@}
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/** @defgroup scm-parenssm-ssm-facet syntaxstatemachine facet methods **/
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///@{
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/** identifies this ssm **/
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syntaxstatetype ssm_type() const noexcept;
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/** text describing expected/allowed input to this ssm in current state. **/
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std::string_view get_expect_str() const noexcept;
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/** update ssm for token @p tk, with overall state in @p p_psm **/
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void on_token(const Token & tk,
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ParserStateMachine * p_psm);
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/** update ssm for expression @p expr (emitted by nested ssm),
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* with overall parser state in @p p_psm
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**/
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void on_parsed_expression(obj<AExpression> expr,
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ParserStateMachine * p_psm);
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/** update ssm for expression @p expr (emitted by nested ssm)
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* that's immediately followed by token @p tk
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* with overall parser state in @p p_psm
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**/
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void on_parsed_expression_with_token(obj<AExpression> expr,
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const Token & tk,
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ParserStateMachine * p_psmn);
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///@}
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/** @defgroup scm-parenssm-printable-facet printable facet methods **/
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///@{
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bool pretty(const ppindentinfo & ppii) const;
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///@}
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private:
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/** @defgroup scm-parenssm-member-vars **/
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///@{
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/** identify paren-expression state **/
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parenexprstatetype parenstate_;
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/** scaffold expression (representing parenthesized value) here **/
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obj<AExpression> expr_;
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///@}
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};
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} /*namespace scm*/
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} /*namespace xo*/
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/* end DParenSsm.hpp */
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