[10031] | 1 | #region License Information
|
---|
| 2 | /* HeuristicLab
|
---|
| 3 | * Copyright (C) 2002-2013 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
|
---|
| 4 | *
|
---|
| 5 | * This file is part of HeuristicLab.
|
---|
| 6 | *
|
---|
| 7 | * HeuristicLab is free software: you can redistribute it and/or modify
|
---|
| 8 | * it under the terms of the GNU General Public License as published by
|
---|
| 9 | * the Free Software Foundation, either version 3 of the License, or
|
---|
| 10 | * (at your option) any later version.
|
---|
| 11 | *
|
---|
| 12 | * HeuristicLab is distributed in the hope that it will be useful,
|
---|
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
|
---|
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
---|
| 15 | * GNU General Public License for more details.
|
---|
| 16 | *
|
---|
| 17 | * You should have received a copy of the GNU General Public License
|
---|
| 18 | * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
|
---|
| 19 | */
|
---|
| 20 | #endregion
|
---|
| 21 |
|
---|
| 22 | using System;
|
---|
| 23 | using System.Collections.Generic;
|
---|
| 24 | using System.Linq;
|
---|
| 25 | using System.Text.RegularExpressions;
|
---|
| 26 |
|
---|
| 27 | namespace HeuristicLab.Grammars {
|
---|
| 28 | using Sequence = IEnumerable<string>;
|
---|
| 29 |
|
---|
| 30 | public class Grammar : IGrammar {
|
---|
| 31 | private Dictionary<string, List<Sequence>> rules = new Dictionary<string, List<Sequence>>();
|
---|
| 32 | private HashSet<string> allSymbols = new HashSet<string>();
|
---|
| 33 |
|
---|
| 34 | public string StartSymbol { get; set; }
|
---|
| 35 | public IEnumerable<string> TerminalSymbols { get { return allSymbols.Except(NonTerminalSymbols); } }
|
---|
| 36 | public IEnumerable<string> NonTerminalSymbols { get { return rules.Keys; } }
|
---|
| 37 | public IEnumerable<string> Symbols { get { return allSymbols; } }
|
---|
| 38 |
|
---|
| 39 | public Grammar(string startSymbol) {
|
---|
| 40 | this.StartSymbol = startSymbol;
|
---|
| 41 | }
|
---|
| 42 |
|
---|
| 43 | public int NumberOfAlternatives(string ntSymbol) {
|
---|
| 44 | return rules[ntSymbol].Count;
|
---|
| 45 | }
|
---|
| 46 |
|
---|
| 47 | public IEnumerable<Sequence> GetAlternatives(string ntSymbol) {
|
---|
| 48 | return rules[ntSymbol].AsReadOnly();
|
---|
| 49 | }
|
---|
| 50 |
|
---|
| 51 | public Sequence GetAlternative(string ntSymbol, int index) {
|
---|
| 52 | return rules[ntSymbol][index];
|
---|
| 53 | }
|
---|
| 54 |
|
---|
| 55 | public void AddProductionRule(string ntSymbol, Sequence production) {
|
---|
| 56 | List<Sequence> l;
|
---|
| 57 | if (!rules.TryGetValue(ntSymbol, out l)) {
|
---|
| 58 | l = new List<Sequence>();
|
---|
| 59 | rules.Add(ntSymbol, l);
|
---|
| 60 |
|
---|
| 61 | allSymbols.Add(ntSymbol); // register new nt-symbol
|
---|
| 62 | }
|
---|
| 63 | l.Add(production);
|
---|
| 64 |
|
---|
| 65 | foreach (var s in production) allSymbols.Add(s); // register all symbols in the production
|
---|
| 66 | }
|
---|
| 67 |
|
---|
| 68 | private static Regex ruleExpr = new Regex(@"\s*(?<ntSymbol>\w+)\s*->\s*(?<alternative>\w+(?:\s+\w+)*)(?:\s*\|\s*(?<alternative>\w+(?:\s+\w+)*))*");
|
---|
| 69 | private static Regex empty = new Regex(@"^\s*$");
|
---|
| 70 | public static IGrammar FromString(string gStr) {
|
---|
| 71 | var lines = gStr.Split(new string[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries);
|
---|
| 72 | lines = lines.Where(l => !empty.IsMatch(l)).ToArray(); // remove empty lines
|
---|
| 73 |
|
---|
| 74 | // first line is the rule for the start-symbol
|
---|
| 75 | var m = ruleExpr.Match(lines.First());
|
---|
| 76 | var startSymbol = m.Groups["ntSymbol"].Value;
|
---|
| 77 | var g = new Grammar(startSymbol);
|
---|
| 78 | foreach (var alt in m.Groups["alternative"].Captures) {
|
---|
| 79 | g.AddProductionRule(startSymbol, alt.ToString().Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries));
|
---|
| 80 | }
|
---|
| 81 | foreach (var line in lines.Skip(1)) {
|
---|
| 82 | m = ruleExpr.Match(line);
|
---|
| 83 | var ntSymbol = m.Groups["ntSymbol"].Value;
|
---|
| 84 | foreach (var alt in m.Groups["alternative"].Captures) {
|
---|
| 85 | g.AddProductionRule(ntSymbol, alt.ToString().Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries));
|
---|
| 86 | }
|
---|
| 87 | }
|
---|
| 88 | return g;
|
---|
| 89 | }
|
---|
| 90 | }
|
---|
| 91 | } |
---|