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162
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1 using Implab;
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2 using System;
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3 using System.Linq;
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4
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5 namespace Implab.Automaton.RegularExpressions {
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6 public abstract class Token<TTag> {
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7 public abstract void Accept(IVisitor<TTag> visitor);
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8
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9 public Token<TTag> Extend() {
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10 return Cat(new EndToken<TTag>());
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11 }
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12
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13 public Token<TTag> Tag<T>(T tag) where T : IConvertible {
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14 return Cat(new EndToken<TTag>(tag));
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15 }
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16
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17 public Token<TTag> Cat(Token<TTag> right) {
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18 return new CatToken<TTag>(this, right);
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19 }
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20
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21 public Token<TTag> Or(Token<TTag> right) {
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22 return new AltToken<TTag>(this, right);
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23 }
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24
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25 public Token<TTag> Optional() {
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26 return Or(new EmptyToken<TTag>());
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27 }
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28
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29 public Token<TTag> EClosure() {
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30 return new StarToken<TTag>(this);
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31 }
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32
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33 public Token<TTag> Closure() {
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34 return Cat(new StarToken<TTag>(this));
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35 }
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36
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37 public Token<TTag> Repeat(int count) {
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38 Token<TTag> token = null;
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39
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40 for (int i = 0; i < count; i++)
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41 token = token != null ? token.Cat(this) : this;
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42 return token ?? new EmptyToken<TTag>();
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43 }
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44
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45 public Token<TTag> Repeat(int min, int max) {
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46 if (min > max || min < 1)
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47 throw new ArgumentOutOfRangeException();
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48 var token = Repeat(min);
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49
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50 for (int i = min; i < max; i++)
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51 token = token.Cat( this.Optional() );
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52 return token;
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53 }
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54
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55 public static Token<TTag> New<T>(params T[] set) where T : struct, IConvertible {
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56 Safe.ArgumentNotNull(set, "set");
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57 Token<TTag> token = null;
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58 foreach(var c in set.Distinct())
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59 token = token == null ? new SymbolToken<TTag>(c) : token.Or(new SymbolToken<TTag>(c));
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60 return token;
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61 }
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62 }
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63 }
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