public AlphabetBuilder(RxNode <TLetter> expression, TLetter?eof = null, RangeSet <TLetter>?validRanges = default)
        {
            var eofRange = eof.HasValue ? new RangeSet <TLetter>(eof.Value) : RangeSet <TLetter> .Empty;
            // Step 1: Find all charset-generating regular expression parts
            var visitor = new AlphabetBuilderVisitor <TLetter>();

            expression.Visit(visitor, (letters, negate) => letters - eofRange);
            var charsets = visitor.Charsets;
            // Step 2: Get all ranges of all used charsets and register their "users"
            var ranges = MakeRanges(charsets, (validRanges ?? RangeSet <TLetter> .All) - eofRange);
            // Step 3: Group the information into alphabet entries
            var alphabetByKey = ranges
                                .GroupBy <UsedLetterRange <TLetter>, string, Range <TLetter> >(r => r.GetUsersKey(), r => r.Range)
                                .Select((g, ix) => new KeyValuePair <string, AlphabetLetter <TLetter> >(g.Key, new AlphabetLetter <TLetter>(new LetterId(ix + 1), new RangeSet <TLetter>(g))))
                                .ToDictionary(p => p.Key, p => p.Value);

            // Step 4: Store alphabet entries for each regex part
            foreach (var range in ranges)
            {
                var alphabetEntry = alphabetByKey[range.GetUsersKey()];
                for (var rangeUser = range.Users; rangeUser != null; rangeUser = rangeUser.Next)
                {
                    charsets[rangeUser.User].Value.Add(alphabetEntry.Id);
                }
            }
            // Step 5: store alphabet information
            this.AlphabetById = alphabetByKey.Values.ToDictionary(e => e.Id, e => e.Ranges);
            this.AlphabetById.Add(LetterId.Eof, eofRange);             // EOF
            // Step 6: rebuild expression
            this.Expression = expression.Visit(new AlphabetLetterVisitor <TLetter>(), node => charsets[visitor.GetId(node)].Value);
        }
Exemplo n.º 2
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        public static Nfa <TLetter> Build(RxNode <TLetter> node)
        {
            var builder  = new NfaBuilder <TLetter>();
            var endState = node.Visit(builder, builder.startState);

            return(new Nfa <TLetter>(builder.states, builder.startState, endState));
        }
Exemplo n.º 3
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 public static RxNode <TLetter> Extract(RxNode <TLetter> rx, SymbolId symbolId)
 {
     return(rx.Visit(new RxOfSymbol <TLetter>(), symbolId));
 }
Exemplo n.º 4
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 public void Add(SymbolId symbol, RxNode <TLetter> regex)
 {
     this.tokens.Add(symbol, regex);
 }