/****************************************************************************
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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.Diagnostics;
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using System.Linq;
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using System.Text.RegularExpressions;
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namespace QtVsTools.SyntaxAnalysis
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{
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public abstract partial class RegExpr
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{
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////////////////////////////////////////////////////////////////////////////////////////////
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///
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/// RegExpr.Parser
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///
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////////////////////////////////////////////////////////////////////////////////////////////
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/// <summary>
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/// Rendering of <see cref="RegExpr"/>
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/// </summary>
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public partial class Parser
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{
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Renderer Renderer { get; set; }
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Pattern Pattern { get; set; }
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public Regex Regex { get; private set; }
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internal Parser(RegExpr expr, RegExpr defaultTokenWs = null)
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{
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Renderer = new Renderer();
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Refresh(expr, defaultTokenWs);
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}
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/// <summary>
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/// Parse input text and return productions.
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/// </summary>
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/// <remarks>
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/// The parsing procedure will first calculate the parse tree corresponding to the input
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/// text, given the token data captured. The parse tree is then used to generate all
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/// productions, according to the production rules defined for each token.
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/// (see also <see cref="GetProductions(ParseTreeNode)"/>)
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/// </remarks>
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/// <param name="text">Text to be parsed.</param>
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/// <returns>Productions by token id</returns>
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public ProductionObjects Parse(string text)
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{
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var parseTree = GetParseTree(text);
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return GetProductionObjects(parseTree);
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}
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public void Refresh(RegExpr expr, RegExpr defaultTokenWs = null)
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{
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// Render Regex string
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Pattern = Renderer.RenderPattern(expr, defaultTokenWs);
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// Compile Regex
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Regex = new Regex(Pattern.ExprRender, RegexOptions.Multiline);
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}
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/// <summary>
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/// Parse input text using Regex and generate corresponding parse tree.
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/// </summary>
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/// <param name="text">Text to be parsed</param>
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/// <returns>Parse tree</returns>
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ParseTree GetParseTree(string text)
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{
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// Match regex pattern
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var match = Regex.Match(text);
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if (!match.Success || match.Length == 0)
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throw new ParseErrorException();
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// Flat list of parse-tree nodes, from Regex captures
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var nodes = match.Groups.Cast<Group>()
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.SelectMany((group, groupIdx) => group.Captures.Cast<Capture>()
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.Where(capture => !string.IsNullOrEmpty(capture.Value))
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.Select((capture, captureIdx) => new ParseTree.Node
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{
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CaptureId = Regex.GroupNameFromNumber(groupIdx),
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Token = Pattern.Tokens[Regex.GroupNameFromNumber(groupIdx)],
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Value = capture.Value,
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Begin = capture.Index,
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End = capture.Index + capture.Length,
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GroupIdx = groupIdx,
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CaptureIdx = captureIdx,
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}))
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.OrderBy(c => c.Begin)
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.ToList();
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// Node list partitioned by token
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var nodesByToken = nodes
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.GroupBy(node => node.Token)
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.ToDictionary(g => g.Key, g => g.ToArray());
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foreach (var node in nodes.Where(n => n.Token != Pattern.Root)) {
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// Get nodes captured by parent token
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Token parentToken;
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if (!node.Token.Parents.TryGetValue(node.CaptureId, out parentToken))
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throw new ParseErrorException("Unknown capture ID");
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ParseTree.Node[] parentNodes;
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if (!nodesByToken.TryGetValue(parentToken, out parentNodes))
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throw new ParseErrorException("Missing parent nodes");
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// Find parent node
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int idx = Array.BinarySearch(parentNodes, node, ParseTree.Node.Comparer);
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if (idx < 0) {
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idx = (~idx) - 1;
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if (idx < 0)
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throw new ParseErrorException("Parent node not found");
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}
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// Attach to parent node
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(node.Parent = parentNodes[idx]).ChildNodes.Add(node.Begin, node);
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}
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// Return parse tree root
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return nodesByToken[Pattern.Root].FirstOrDefault();
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}
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}
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public class ParseErrorException : RegExprException
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{
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public ParseErrorException(string message = null) : base(message) { }
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}
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}
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}
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