119 lines
4 KiB
C++
119 lines
4 KiB
C++
/* @file apply_xs.hpp */
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#pragma once
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#include "exprstate.hpp"
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#include "xo/expression/Apply.hpp"
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namespace xo {
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namespace scm {
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/**
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* fn ( arg1 , arg2 , .. , argn )
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* ^ ^ ^ ^ ^ ^ ^ ^ ^
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* | | | | | | | | (done)
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* | | | | | | | apply_3
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* | | | | | | apply_2:expect_rhs_expression
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* | | | | | apply_3
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* | | | | apply_2:expect_rhs_expression
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* | | | apply_3
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* | | apply_2:expect_rhs_expression
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* | apply_1
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* apply_0:expect_rhs_expression
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*
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* apply_0 --on_expr()--> apply_1
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* apply_1 --on_leftparen()--> apply_2
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* apply_2 --on_expr()--> apply_3
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* apply_3 --on_comma()--> apply_2
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* --on_rightparen()-> (done)
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*
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* apply_0: start
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* apply_1: leftparen following expr allows parser to recognize apply
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* apply_2: expect next argument
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* apply_3: got argument, expect comma or rightparen to continue
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* (done): apply complete, pop exprstate from stack
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*
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* In practice will start in state apply_1
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**/
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enum class applyexprstatetype {
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invalid = -1,
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apply_0,
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apply_1,
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apply_2,
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apply_3,
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n_applyexprstatetype
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};
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extern const char * applyexprstatetype_descr(applyexprstatetype x);
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std::ostream &
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operator<<(std::ostream & os, applyexprstatetype x);
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/** @class apply_xs
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* @brief state machine for parsing a schematic function-call-expression
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*
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*/
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class apply_xs : public exprstate {
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public:
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using Apply = xo::scm::Apply;
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public:
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explicit apply_xs();
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virtual ~apply_xs() = default;
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/** downcast from parent type **/
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static const apply_xs * from(const exprstate * x) {
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return dynamic_cast<const apply_xs *>(x);
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}
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/**
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* Start apply. Will trigger this after input like
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* "fn("
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*
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* apply_xs remains on expr stack until closing right paren
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* fn(arg1-expr, arg2-expr, ...)
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*
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* @p fnex expression in function position
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* @p p_psm parser state machine
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**/
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static void start(rp<Expression> fnex,
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parserstatemachine * p_psm);
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virtual const char * get_expect_str() const override;
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virtual void on_expr(bp<Expression> expr,
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parserstatemachine * p_psm) override;
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virtual void on_comma_token(const token_type & tk,
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parserstatemachine * p_psm) override;
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virtual void on_leftparen_token(const token_type & tk,
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parserstatemachine * p_psm) override;
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virtual void on_rightparen_token(const token_type & tk,
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parserstatemachine * p_psm) override;
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virtual void print(std::ostream & os) const override;
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virtual bool pretty_print(const print::ppindentinfo & ppii) const final override;
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private:
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static std::unique_ptr<apply_xs> make();
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private:
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/** current state of parser for this apply expression **/
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applyexprstatetype applyxs_type_ = applyexprstatetype::apply_0;
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/** evaluates to function to be invoked **/
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rp<Expression> fn_expr_;
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/** evaluates to the arguments to pass to @ref fn_ **/
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std::vector<rp<Expression>> args_expr_v_;
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};
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} /*namespace scm */
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namespace print {
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#ifndef ppdetail_atomic
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PPDETAIL_ATOMIC(xo::scm::applyexprstatetype);
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#endif
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}
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} /*namespace xo*/
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/* end apply_xs.hpp */
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