Mercurial > pub > ImplabNet

comparison Implab/Formats/Grammar.cs @ 177:a0ff6a0e9c44 ref20160224

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
refactoring
author cin
date Wed, 23 Mar 2016 01:42:00 +0300
parents
children d5c5db0335ee
comparison
equal deleted inserted replaced
176:0c3c69fe225b 177:a0ff6a0e9c44
1 using Implab;
2 using System;
3 using System.Collections.Generic;
4 using System.Linq;
5 using Implab.Automaton;
6 using Implab.Automaton.RegularExpressions;
7
8 namespace Implab.Formats {
9 /// <summary>
10 /// Базовый абстрактный класс. Грамматика, позволяет формулировать выражения над алфавитом типа <c>char</c>.
11 /// </summary>
12 public abstract class Grammar<TSymbol, TTag> {
13
14 protected abstract IAlphabetBuilder<TSymbol> AlphabetBuilder {
15 get;
16 }
17
18 protected SymbolToken<TTag> UnclassifiedToken() {
19 return new SymbolToken<TTag>(DFAConst.UNCLASSIFIED_INPUT);
20 }
21
22 protected void DefineAlphabet(IEnumerable<TSymbol> alphabet) {
23 Safe.ArgumentNotNull(alphabet, "alphabet");
24
25 foreach (var ch in alphabet)
26 AlphabetBuilder.DefineSymbol(ch);
27 }
28
29 protected Token<TTag> SymbolToken(TSymbol symbol) {
30 return Token<TTag>.New(TranslateOrAdd(symbol));
31 }
32
33 protected Token<TTag> SymbolToken(IEnumerable<TSymbol> symbols) {
34 Safe.ArgumentNotNull(symbols, "symbols");
35
36 return Token<TTag>.New(TranslateOrAdd(symbols).ToArray());
37 }
38
39 protected Token<TTag> SymbolSetToken(params TSymbol[] set) {
40 return SymbolToken(set);
41 }
42
43 int TranslateOrAdd(TSymbol ch) {
44 var t = AlphabetBuilder.Translate(ch);
45 if (t == DFAConst.UNCLASSIFIED_INPUT)
46 t = AlphabetBuilder.DefineSymbol(ch);
47 return t;
48 }
49
50 IEnumerable<int> TranslateOrAdd(IEnumerable<TSymbol> symbols) {
51 return symbols.Distinct().Select(TranslateOrAdd);
52 }
53
54 int TranslateOrDie(TSymbol ch) {
55 var t = AlphabetBuilder.Translate(ch);
56 if (t == DFAConst.UNCLASSIFIED_INPUT)
57 throw new ApplicationException(String.Format("Symbol '{0}' is UNCLASSIFIED", ch));
58 return t;
59 }
60
61 IEnumerable<int> TranslateOrDie(IEnumerable<TSymbol> symbols) {
62 return symbols.Distinct().Select(TranslateOrDie);
63 }
64
65 protected Token<TTag> SymbolTokenExcept(IEnumerable<TSymbol> symbols) {
66 Safe.ArgumentNotNull(symbols, "symbols");
67
68 return Token<TTag>.New( Enumerable.Range(0, AlphabetBuilder.Count).Except(TranslateOrDie(symbols)).ToArray() );
69 }
70
71 protected abstract IndexedAlphabetBase<TSymbol> CreateAlphabet();
72
73 protected ScannerContext<TTag> BuildScannerContext(Token<TTag> regexp) {
74
75 var dfa = new RegularDFA<TSymbol, TTag>(AlphabetBuilder);
76
77 var visitor = new RegularExpressionVisitor<TTag>();
78 regexp.Accept( visitor );
79
80 visitor.BuildDFA(dfa);
81
82 if (dfa.IsFinalState(dfa.InitialState))
83 throw new ApplicationException("The specified language contains empty token");
84
85 var ab = CreateAlphabet();
86 var optimal = dfa.Optimize(ab);
87
88 return new ScannerContext<TTag>(
89 optimal.CreateTransitionTable(),
90 optimal.CreateFinalStateTable(),
91 optimal.CreateTagTable(),
92 optimal.InitialState,
93 ab.GetTranslationMap()
94 );
95 }
96
97 }
98
99
100 }