127 lines
2.2 KiB
C++
127 lines
2.2 KiB
C++
#pragma once
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#include <string>
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class Expression
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{
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public:
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virtual bool Eval() const = 0;
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virtual unsigned int Size() const = 0;
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virtual unsigned int VarCount() const = 0;
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};
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class IdentifierExpression : public Expression
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{
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public:
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static IdentifierExpression p;
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static IdentifierExpression q;
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static IdentifierExpression r;
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static IdentifierExpression s;
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public:
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void SetTruthValue(bool value)
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{
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truthValue = value;
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}
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bool Eval() const override
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{
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return truthValue;
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}
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unsigned int Size() const override { return 1; }
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unsigned int VarCount() const override {return 1; }
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private:
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IdentifierExpression() :
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truthValue(false)
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{ }
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private:
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bool truthValue;
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};
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class NegationExpression : public Expression
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{
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public:
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NegationExpression(const Expression* operand) :
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operand(operand)
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{
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}
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bool Eval() const override
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{
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return !(operand->Eval());
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}
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unsigned int Size() const override { return 1 + operand->Size(); }
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unsigned int VarCount() const override { return operand->VarCount(); }
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private:
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const Expression* operand;
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};
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class BinaryExpression : public Expression
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{
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public:
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BinaryExpression(const Expression* left, const Expression* right) :
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left(left), right(right)
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{
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}
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unsigned int Size() const override { return 1 + left->Size() + right->Size(); }
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unsigned int VarCount() const override { return left->VarCount() + right->VarCount(); }
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protected:
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const Expression* left;
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const Expression* right;
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};
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class ConjunctionExpression : public BinaryExpression
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{
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public:
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using BinaryExpression::BinaryExpression;
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bool Eval() const override
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{
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return left->Eval() && right->Eval();
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}
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};
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class DisjunctionExpression : public BinaryExpression
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{
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public:
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using BinaryExpression::BinaryExpression;
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bool Eval() const override
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{
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return left->Eval() || right->Eval();
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}
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};
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class ImplicationExpression : public BinaryExpression
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{
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public:
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using BinaryExpression::BinaryExpression;
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bool Eval() const override
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{
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return !(left->Eval()) || right->Eval();
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}
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};
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class EquivalenceExpression : public BinaryExpression
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{
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public:
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using BinaryExpression::BinaryExpression;
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bool Eval() const override
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{
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return left->Eval() == right->Eval();
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}
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}; |