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51 lines
1.5 KiB
C++
51 lines
1.5 KiB
C++
/*
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* Copyright (c) Contributors to the Open 3D Engine Project.
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* For complete copyright and license terms please see the LICENSE at the root of this distribution.
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*
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* SPDX-License-Identifier: Apache-2.0 OR MIT
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*
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*/
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#pragma once
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#include <AzCore/std/any.h>
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#include <AzCore/RTTI/RTTI.h>
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#include <AzCore/std/string/string.h>
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#include <ExpressionEvaluation/ExpressionEngine/ExpressionTypes.h>
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#include <ExpressionEngine/InternalTypes.h>
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namespace ExpressionEvaluation
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{
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// Interface for expanding the available grammar for parsing.
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//
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// Must handle both parsing and execution.
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class ExpressionElementParser
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{
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public:
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AZ_CLASS_ALLOCATOR(ExpressionElementParser, AZ::SystemAllocator, 0);
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struct ParseResult
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{
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// Returns the number of characters that the parser wants to consume from the input text.
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size_t m_charactersConsumed = 0;
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ElementInformation m_element;
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};
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protected:
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ExpressionElementParser() = default;
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public:
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virtual ~ExpressionElementParser() = default;
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virtual ExpressionParserId GetParserId() const = 0;
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// Attempt to parse the specified element in the text at the specified offset.
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virtual ParseResult ParseElement(const AZStd::string& inputText, size_t offset) const = 0;
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// Evaluate the given token using the current evaluation stack.
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virtual void EvaluateToken(const ElementInformation& parseResult, ExpressionResultStack& evaluationStack) const = 0;
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};
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}
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