/****************************************************************************
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**
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** Copyright (C) 2019 The Qt Company Ltd.
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** Contact: https://www.qt.io/licensing/
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**
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** This file is part of the Qt VS Tools.
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**
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** $QT_BEGIN_LICENSE:GPL-EXCEPT$
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** Commercial License Usage
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** Licensees holding valid commercial Qt licenses may use this file in
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** accordance with the commercial license agreement provided with the
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** Software or, alternatively, in accordance with the terms contained in
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** a written agreement between you and The Qt Company. For licensing terms
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** and conditions see https://www.qt.io/terms-conditions. For further
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** information use the contact form at https://www.qt.io/contact-us.
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**
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** GNU General Public License Usage
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** Alternatively, this file may be used under the terms of the GNU
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** General Public License version 3 as published by the Free Software
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** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
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** included in the packaging of this file. Please review the following
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** information to ensure the GNU General Public License requirements will
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** be met: https://www.gnu.org/licenses/gpl-3.0.html.
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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using System;
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using System.Collections.Generic;
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using System.Text;
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namespace QtVsTools.SyntaxAnalysis
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{
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/// <summary>
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/// Regular expression quantifier.
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/// </summary>
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public class RegExprRepeat : RegExpr
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{
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public int AtLeast { get; set; }
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public int AtMost { get; set; }
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public RegExpr Expr { get; set; }
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bool ExprNeedsGroup
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{
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get
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{
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return (Expr is RegExprSequence)
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|| (Expr is RegExprLiteral
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&& NeedsGroup(Expr.As<RegExprLiteral>().LiteralExpr));
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}
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}
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protected override IEnumerable<RegExpr> OnRender(RegExpr defaultTokenWs, RegExpr parent,
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StringBuilder pattern, ref RenderMode mode, Stack<Token> tokenStack)
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{
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base.OnRender(defaultTokenWs, parent, pattern, ref mode, tokenStack);
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if (ExprNeedsGroup)
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pattern.Append("(?:");
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return Items(Expr);
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}
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protected override void OnRenderEnd(RegExpr defaultTokenWs, RegExpr parent,
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StringBuilder pattern, ref RenderMode mode, Stack<Token> tokenStack)
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{
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base.OnRenderEnd(defaultTokenWs, parent, pattern, ref mode, tokenStack);
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if (ExprNeedsGroup)
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pattern.Append(")");
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if (AtLeast == 0 && AtMost == 1)
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pattern.Append("?");
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else if (AtLeast == 0 && AtMost == int.MaxValue)
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pattern.Append("*");
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else if (AtLeast == 1 && AtMost == int.MaxValue)
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pattern.Append("+");
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else if (AtLeast == AtMost)
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pattern.AppendFormat("{{{0}}}", AtLeast);
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else if (AtMost == int.MaxValue)
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pattern.AppendFormat("{{{0},}}", AtLeast);
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else if (AtLeast == 0)
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pattern.AppendFormat("{{,{0}}}", AtMost);
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else
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pattern.AppendFormat("{{{0},{1}}}", AtLeast, AtMost);
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}
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}
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public abstract partial class RegExpr
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{
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public RegExpr Optional()
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{
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return Repeat(0, 1);
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}
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public RegExpr Repeat(int count)
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{
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return Repeat(count, count);
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}
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public RegExpr Repeat(int atLeast = 0, int atMost = int.MaxValue)
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{
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if (this is RegExprRepeat)
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throw new NestedRepeatException();
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return new RegExprRepeat
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{
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AtLeast = atLeast,
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AtMost = atMost,
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Expr = this
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};
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}
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public class NestedRepeatException : RegExprException
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{
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public NestedRepeatException(string message = null) : base(message) { }
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}
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}
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}
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