Mercurial > pub > ImplabNet
view Implab/Automaton/RegularExpressions/Grammar.cs @ 167:96681e9d0cea ref20160224
sync
author | cin |
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date | Wed, 02 Mar 2016 00:20:48 +0300 |
parents | e227e78d72e4 |
children | 92d5278d1b10 |
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using Implab; using System; using System.Collections.Generic; using System.Linq; namespace Implab.Automaton.RegularExpressions { /// <summary> /// Базовый абстрактный класс. Грамматика, позволяет формулировать выражения над алфавитом типа <c>char</c>. /// </summary> public abstract class Grammar<TSymbol, TTag> { protected abstract IAlphabetBuilder<TSymbol> AlphabetBuilder { get; } protected SymbolToken<TTag> UnclassifiedToken() { return new SymbolToken<TTag>(DFAConst.UNCLASSIFIED_INPUT); } protected void DefineAlphabet(IEnumerable<TSymbol> alphabet) { Safe.ArgumentNotNull(alphabet, "alphabet"); foreach (var ch in alphabet) AlphabetBuilder.DefineSymbol(ch); } protected Token<TTag> SymbolToken(TSymbol symbol) { return Token<TTag>.New(TranslateOrAdd(symbol)); } protected Token<TTag> SymbolToken(IEnumerable<TSymbol> symbols) { Safe.ArgumentNotNull(symbols, "symbols"); return Token<TTag>.New(TranslateOrAdd(symbols).ToArray()); } protected Token<TTag> SymbolSetToken(params TSymbol[] set) { return SymbolToken(set); } int TranslateOrAdd(TSymbol ch) { var t = AlphabetBuilder.Translate(ch); if (t == DFAConst.UNCLASSIFIED_INPUT) t = AlphabetBuilder.DefineSymbol(ch); return t; } IEnumerable<int> TranslateOrAdd(IEnumerable<TSymbol> symbols) { return symbols.Distinct().Select(TranslateOrAdd); } int TranslateOrDie(TSymbol ch) { var t = AlphabetBuilder.Translate(ch); if (t == DFAConst.UNCLASSIFIED_INPUT) throw new ApplicationException(String.Format("Symbol '{0}' is UNCLASSIFIED", ch)); return t; } IEnumerable<int> TranslateOrDie(IEnumerable<TSymbol> symbols) { return symbols.Distinct().Select(TranslateOrDie); } protected Token<TTag> SymbolTokenExcept(IEnumerable<TSymbol> symbols) { Safe.ArgumentNotNull(symbols, "symbols"); return Token<TTag>.New( Enumerable.Range(0, AlphabetBuilder.Count).Except(TranslateOrDie(symbols)).ToArray() ); } protected void BuildDFA(Token<TTag> lang, IDFATableBuilder<TTag> dfaTable, IAlphabetBuilder<TSymbol> dfaAlphabet) { Safe.ArgumentNotNull(lang, "lang"); Safe.ArgumentNotNull(dfaAlphabet, "dfaAlphabet"); var dfa = new RegularDFADefinition<TSymbol, TTag>(AlphabetBuilder); var builder = new RegularDFABuilder<TTag>(); lang.Accept( builder ); builder.BuildDFA(dfa); if (dfa.IsFinalState(dfa.InitialState)) throw new ApplicationException("The specified language contains empty token"); dfa.Optimize(dfaTable, dfaAlphabet); } } }