124 lines
4.2 KiB
C++
124 lines
4.2 KiB
C++
/** @file IfExpr.hpp
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*
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* Author: Roland Conybeare
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**/
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#pragma once
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#include "Expression.hpp"
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#include <vector>
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#include <string>
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//#include <cstdint>
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namespace xo {
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namespace ast {
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/** @class IfExpr
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* @brief abstract syntax tree for a function definition
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*
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**/
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class IfExpr : public Expression {
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public:
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using TypeDescr = xo::reflect::TypeDescr;
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public:
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/** create expression for conditional execution of
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* @p when_true or @p when_false, depending on result
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* of evaluating expression @p test
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**/
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static ref::rp<IfExpr> make(const ref::rp<Expression> & test,
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const ref::rp<Expression> & when_true,
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const ref::rp<Expression> & when_false);
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/** downcast from Expression **/
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static ref::brw<IfExpr> from(ref::brw<Expression> x) {
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return ref::brw<IfExpr>::from(x);
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}
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const ref::rp<Expression> & test() const { return test_; }
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const ref::rp<Expression> & when_true() const { return when_true_; }
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const ref::rp<Expression> & when_false() const { return when_false_; }
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// ----- Expression -----
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virtual std::set<std::string> get_free_variables() const override {
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std::set<std::string> retval = test_->get_free_variables();
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std::set<std::string> free_vars;
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free_vars = when_true_->get_free_variables();
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for (const auto & s : free_vars)
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retval.insert(s);
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free_vars = when_false_->get_free_variables();
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for (const auto & s : free_vars)
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retval.insert(s);
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return retval;
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}
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virtual std::size_t visit_preorder(VisitFn visitor_fn) override {
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std::size_t n = 1;
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visitor_fn(this);
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n += this->when_true_->visit_preorder(visitor_fn);
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n += this->when_false_->visit_preorder(visitor_fn);
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return n;
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}
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virtual void attach_envs(ref::brw<Environment> p) override {
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test_->attach_envs(p);
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when_true_->attach_envs(p);
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when_false_->attach_envs(p);
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}
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#ifdef NOT_USING
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virtual std::int32_t find_free_vars(std::set<ref::brw<Variable>> * p_set) override {
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return (test_->find_free_vars(p_set)
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+ when_true_->find_free_vars(p_set)
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+ when_false_->find_free_vars(p_set));
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}
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#endif
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virtual void display(std::ostream & os) const override;
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private:
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/**
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* @p ifexpr_type type for value produced by if-expression.
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* same as both when_true->valuetype() and
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* when_false->valuetype().
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* @p test test-expression; always execute
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* @p when_true then-branch; executes only when test succeeds
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* @p when_false else-branch; executes only when test fails
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**/
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IfExpr(TypeDescr ifexpr_type,
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const ref::rp<Expression> & test,
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const ref::rp<Expression> & when_true,
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const ref::rp<Expression> & when_false)
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: Expression(exprtype::ifexpr, ifexpr_type),
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test_{test},
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when_true_{when_true},
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when_false_{when_false} {}
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private:
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/** if:
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* (if x y z)
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*
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* executes x; if true execute y; otherwise execute z
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**/
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ref::rp<Expression> test_;
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ref::rp<Expression> when_true_;
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ref::rp<Expression> when_false_;
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}; /*IfExpr*/
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inline ref::rp<IfExpr>
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make_ifexpr(const ref::rp<Expression> & test,
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const ref::rp<Expression> & when_true,
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const ref::rp<Expression> & when_false)
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{
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return IfExpr::make(test, when_true, when_false);
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}
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} /*namespace ast*/
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} /*namespace xo*/
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/** end IfExpr.hpp **/
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