Esempio n. 1
0
        static MatchResult Match(this Pattern pattern,
                                 ReadOnlyList <LeafPattern> left,
                                 ReadOnlyList <LeafPattern> collected)
        {
            switch (pattern)
            {
            case Required required:
            {
                var l = left;
                var c = collected;
                foreach (var child in required.Children)
                {
                    bool matched;
                    (matched, l, c) = child.Match(l, c);
                    if (!matched)
                    {
                        return(new MatchResult(false, left, collected));
                    }
                }
                return(new MatchResult(true, l, c));
            }

            case Either either:
            {
                var match = new MatchResult(false, left, collected);
                foreach (var child in either.Children)
                {
                    if (child.Match(left, collected) is (true, var l, var c) &&
                        (!match || l.Count < match.Left.Count))
                    {
                        match = new MatchResult(true, l, c);
                    }
                }
                return(match);
            }

            case Optional optional:
            {
                var l = left;
                var c = collected;
                foreach (var child in optional.Children)
                {
                    (_, l, c) = child.Match(l, c);
                }
                return(new MatchResult(true, l, c));
            }

            case OneOrMore oneOrMore:
            {
                Debug.Assert(oneOrMore.Children.Count == 1);
                var l = left;
                var c = collected;
                ReadOnlyList <LeafPattern>?l_ = null;
                var matched = true;
                var times   = 0;
                while (matched)
                {
                    // could it be that something didn't match but changed l or c?
                    (matched, l, c) = oneOrMore.Children[0].Match(l, c);
                    times          += matched ? 1 : 0;
                    if (l_ != null && l_.Equals(l))
                    {
                        break;
                    }
                    l_ = l;
                }
                if (times >= 1)
                {
                    return(new MatchResult(true, l, c));
                }
                return(new MatchResult(false, left, collected));
            }

            case Command command:
            {
                for (var i = 0; i < left.Count; i++)
                {
                    if (left[i] is Argument {
                            Value: { } value
                        })
                    {
                        if (value.ToString() == command.Name)
                        {
                            return(MatchLeaf(command, i, new Command(command.Name, new ValueObject(true))));
                        }
                        break;
                    }
                }
Esempio n. 2
0
 public static MatchResult Match(this Pattern pattern, ReadOnlyList <LeafPattern> left)
 {
     return(pattern.Match(left, new ReadOnlyList <LeafPattern>()));
 }