Grammar.cs
108 lines
| 3.4 KiB
| text/x-csharp
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r55 | using Implab; | ||
| using System; | ||||
| using System.Collections.Generic; | ||||
| using System.Linq; | ||||
| using System.Text; | ||||
| using System.Threading.Tasks; | ||||
| namespace Implab.Parsing { | ||||
| /// <summary> | ||||
| /// Базовый абстрактный класс. Грамматика, позволяет формулировать выражения над алфавитом типа <c>char</c>. | ||||
| /// </summary> | ||||
| /// <typeparam name="TGrammar"></typeparam> | ||||
| public abstract class Grammar<TGrammar> where TGrammar: Grammar<TGrammar>, new() { | ||||
| static TGrammar _instance; | ||||
| public static TGrammar Instance{ | ||||
| get { | ||||
| if (_instance == null) | ||||
| _instance = new TGrammar(); | ||||
| return _instance; | ||||
| } | ||||
| } | ||||
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r158 | readonly CharAlphabet m_alphabet = new CharAlphabet(); | ||
| public CharAlphabet Alphabet { | ||||
| get { return m_alphabet; } | ||||
| } | ||||
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r55 | public SymbolToken UnclassifiedToken() { | ||
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r158 | return new SymbolToken(CharAlphabet.UNCLASSIFIED); | ||
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r55 | } | ||
| public void DefineAlphabet(IEnumerable<char> alphabet) { | ||||
| Safe.ArgumentNotNull(alphabet, "alphabet"); | ||||
| foreach (var ch in alphabet) | ||||
| m_alphabet.DefineSymbol(ch); | ||||
| } | ||||
| public Token SymbolRangeToken(char start, char end) { | ||||
| return SymbolToken(Enumerable.Range(start, end - start + 1).Select(x => (char)x)); | ||||
| } | ||||
| public Token SymbolToken(char symbol) { | ||||
| return Token.New(TranslateOrAdd(symbol)); | ||||
| } | ||||
| public Token SymbolToken(IEnumerable<char> symbols) { | ||||
| Safe.ArgumentNotNull(symbols, "symbols"); | ||||
| return Token.New(TranslateOrAdd(symbols).ToArray()); | ||||
| } | ||||
| public Token SymbolSetToken(params char[] set) { | ||||
| return SymbolToken(set); | ||||
| } | ||||
| int TranslateOrAdd(char ch) { | ||||
| var t = m_alphabet.Translate(ch); | ||||
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r158 | if (t == CharAlphabet.UNCLASSIFIED) | ||
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r55 | t = m_alphabet.DefineSymbol(ch); | ||
| return t; | ||||
| } | ||||
| IEnumerable<int> TranslateOrAdd(IEnumerable<char> symbols) { | ||||
| return symbols.Distinct().Select(TranslateOrAdd); | ||||
| } | ||||
| int TranslateOrDie(char ch) { | ||||
| var t = m_alphabet.Translate(ch); | ||||
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r158 | if (t == CharAlphabet.UNCLASSIFIED) | ||
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r55 | throw new ApplicationException(String.Format("Symbol '{0}' is UNCLASSIFIED", ch)); | ||
| return t; | ||||
| } | ||||
| IEnumerable<int> TranslateOrDie(IEnumerable<char> symbols) { | ||||
| return symbols.Distinct().Select(TranslateOrDie); | ||||
| } | ||||
| public Token SymbolTokenExcept(IEnumerable<char> symbols) { | ||||
| Safe.ArgumentNotNull(symbols, "symbols"); | ||||
| return Token.New( Enumerable.Range(0, m_alphabet.Count).Except(TranslateOrDie(symbols)).ToArray()); | ||||
| } | ||||
| protected CDFADefinition BuildDFA(Token lang) { | ||||
| Safe.ArgumentNotNull(lang, "lang"); | ||||
| var dfa = new CDFADefinition(m_alphabet); | ||||
| var builder = new DFABuilder(); | ||||
| lang.Accept( builder ); | ||||
| builder.BuildDFA(dfa); | ||||
| if (dfa.InitialStateIsFinal) | ||||
| throw new ApplicationException("The specified language contains empty token"); | ||||
| return dfa.Optimize(); | ||||
| } | ||||
| //protected abstract TGrammar CreateInstance(); | ||||
| } | ||||
| } | ||||