##// END OF EJS Templates
rewritten the text scanner
rewritten the text scanner

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r165:e227e78d72e4 ref20160224
r176:0c3c69fe225b ref20160224
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Token.cs
63 lines | 1.9 KiB | text/x-csharp | CSharpLexer
using Implab;
using System;
using System.Linq;
namespace Implab.Automaton.RegularExpressions {
public abstract class Token<TTag> {
public abstract void Accept(IVisitor<TTag> visitor);
public Token<TTag> Extend() {
return Cat(new EndToken<TTag>());
}
public Token<TTag> Tag(TTag tag) {
return Cat(new EndToken<TTag>(tag));
}
public Token<TTag> Cat(Token<TTag> right) {
return new CatToken<TTag>(this, right);
}
public Token<TTag> Or(Token<TTag> right) {
return new AltToken<TTag>(this, right);
}
public Token<TTag> Optional() {
return Or(new EmptyToken<TTag>());
}
public Token<TTag> EClosure() {
return new StarToken<TTag>(this);
}
public Token<TTag> Closure() {
return Cat(new StarToken<TTag>(this));
}
public Token<TTag> Repeat(int count) {
Token<TTag> token = null;
for (int i = 0; i < count; i++)
token = token != null ? token.Cat(this) : this;
return token ?? new EmptyToken<TTag>();
}
public Token<TTag> Repeat(int min, int max) {
if (min > max || min < 1)
throw new ArgumentOutOfRangeException();
var token = Repeat(min);
for (int i = min; i < max; i++)
token = token.Cat( Optional() );
return token;
}
public static Token<TTag> New(params int[] set) {
Safe.ArgumentNotNull(set, "set");
Token<TTag> token = null;
foreach(var c in set.Distinct())
token = token == null ? new SymbolToken<TTag>(c) : token.Or(new SymbolToken<TTag>(c));
return token;
}
}
}