117 lines
4.2 KiB
C++
117 lines
4.2 KiB
C++
/* file DExpectSymbolSsm.hpp
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*
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* author: Roland Conybeare, Aug 2024
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*/
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#pragma once
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#include "ParserStateMachine.hpp"
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//#include "SyntaxStateMachine.hpp"
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#include "syntaxstatetype.hpp"
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#include <xo/indentlog/print/ppindentinfo.hpp>
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#include <xo/facet/obj.hpp>
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namespace xo {
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namespace scm {
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/** @class DExpectSymbolSsm
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* @brief state machine to expect + capture a symbol
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*
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* For example:
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* - lhs in a define-expression
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**/
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class DExpectSymbolSsm {
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public:
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using DArena = xo::mm::DArena;
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using TypeDescr = xo::reflect::TypeDescr;
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using ppindentinfo = xo::print::ppindentinfo;
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public:
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DExpectSymbolSsm();
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/** create instance using memory from @p parser_mm **/
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static DExpectSymbolSsm * make(DArena & parser_mm);
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/** start nested parser expecting a symbol,
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* on top of parser state machine @p p_psm.
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* On success will deliver symbol by invoking
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* .on_symbol(sym, p_psm)
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* to the state machine on top of the stack
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* as of when this start() method invoked
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**/
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static void start(DArena & parser_mm,
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ParserStateMachine * p_psm);
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/** update state for this syntax on incoming token @p tk,
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* with overall parser state in @p p_psm
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**/
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static void on_symbol_token(const Token & tk,
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ParserStateMachine * p_psm);
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/** @defgroup scm-expectsymbol-ssm-facet syntaxstatemachine facet methods **/
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///@{
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/** identifies the ssm implemented here **/
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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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* Intended to drive error mesages
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**/
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std::string_view get_expect_str() const noexcept;
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/** update state for this syntax after parsing a symbol @p sym;
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* overall parser state in @p p_psm.
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*
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* NOTE:
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* might not be obvious that this is unreachable.
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* DExpectSymbolSsm converts a symbol token,
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* and delivers it to parent ssm using this entry point.
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* This method would only be called if consecutive
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* DExpectSymbolSsm instances on parser stack;
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* which scenario never occurs in Schematika syntax
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**/
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void on_parsed_symbol(std::string_view sym,
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ParserStateMachine * p_psm);
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/** update state for this syntax after parsing a type-description @p td
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* in nested state machine.
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* (provided to satisfy ASyntaxStateMachine api. not reachable)
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**/
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void on_parsed_typedescr(TypeDescr td,
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ParserStateMachine * p_psm);
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/** update state for this syntax on incoming token @p tk,
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* overall parser state in @p p_psm.
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**/
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void on_def_token(const Token & tk,
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ParserStateMachine * p_psm);
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/** update state for this syntax on incoming token @p tk,
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* overall parser state in @p p_psm
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**/
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void on_if_token(const Token & tk,
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ParserStateMachine * p_psm);
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/** update state for this syntax on incoming colon token @p tk,
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* overall parser state in @p p_psm
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**/
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void on_colon_token(const Token & tk,
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ParserStateMachine * p_psm);
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/** update state for this syntax on incoming singleassign token @p tk,
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* overall parser state in @p p_psm
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**/
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void on_singleassign_token(const Token & tk,
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ParserStateMachine * p_psm);
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///@}
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/** @defgroup scm-expectsymbol-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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};
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} /*namespace scm*/
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} /*namespace xo*/
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/* end DExpectSymbolSsm.hpp */
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