ExpressionParser.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "Containers/Array.h"
#include "CoreTypes.h"
#include "HAL/PlatformCrt.h"
#include "Misc/ExpressionParserTypes.h"
#include "Templates/ValueOrError.h"
 
namespace ExpressionParser
{
    template <typename CharType>
    using TLexResultType = TValueOrError<TArray<TExpressionToken<CharType>>, FExpressionError>;
 
    template <typename CharType>
    using TCompileResultType = TValueOrError<TArray<TCompiledToken<CharType>>, FExpressionError>;
 
    using LexResultType = TLexResultType<TCHAR>;
    using CompileResultType = TCompileResultType<TCHAR>;
 
    template <typename CharType>
    CORE_API TLexResultType<CharType> Lex(const CharType* InExpression, const TTokenDefinitions<CharType>& TokenDefinitions);
 
    template <typename CharType>
    CORE_API TCompileResultType<CharType> Compile(const CharType* InExpression, const TTokenDefinitions<CharType>& TokenDefinitions, const FExpressionGrammar& InGrammar);
 
    template <typename CharType>
    CORE_API TCompileResultType<CharType> Compile(TArray<TExpressionToken<CharType>> InTokens, const FExpressionGrammar& InGrammar);
 
    template <typename CharType>
    CORE_API FExpressionResult Evaluate(const CharType* InExpression, const TTokenDefinitions<CharType>& InTokenDefinitions, const FExpressionGrammar& InGrammar, const TIOperatorEvaluationEnvironment<CharType>& InEnvironment);
 
    template <typename CharType>
    CORE_API FExpressionResult Evaluate(const TArray<TCompiledToken<CharType>>& CompiledTokens, const TIOperatorEvaluationEnvironment<CharType>& InEnvironment);
 
    template <typename CharType, typename ContextType>
    FExpressionResult Evaluate(const CharType* InExpression, const TTokenDefinitions<CharType>& InTokenDefinitions, const FExpressionGrammar& InGrammar,    const TOperatorJumpTable<ContextType>& InJumpTable, const ContextType* InContext = nullptr)
    {
        TOperatorEvaluationEnvironment<ContextType> Env(InJumpTable, InContext);
        return Evaluate(InExpression, InTokenDefinitions, InGrammar, Env);
    }
 
    template<typename ContextType>
    FExpressionResult Evaluate(const TArray<FCompiledToken>& CompiledTokens, const TOperatorJumpTable<ContextType>& InJumpTable, const ContextType* InContext = nullptr)
    {
        TOperatorEvaluationEnvironment<ContextType> Env(InJumpTable, InContext);
        return Evaluate(CompiledTokens, Env);
    }
}