private IEnumerable <ArgPattern> ParseAtom(ArgTokens tokenParser)
{
// atom ::= '(' expr ')' | '[' expr ']' | 'options'
// | long | shorts | argument | command ;
var token = tokenParser.Current();
var result = new List <ArgPattern>();
switch (token)
{
case "[":
case "(":
{
tokenParser.Move();
string matching;
if (token == "(")
{
matching = ")";
result.Add(new ArgRequired(ParseExpression(tokenParser).ToArray()));
}
else
{
matching = "]";
result.Add(new ArgOptional(ParseExpression(tokenParser).ToArray()));
}
if (tokenParser.Move() != matching)
{
throw new Exception("unmatched '" + token + "'");
}
}
break;
default:
if ((token.StartsWith("<") && token.EndsWith(">")) || token.All(c => Char.IsUpper(c)))
{
result.Add(new ArgArgument(tokenParser.Move()));
}
else if (token.StartsWith("-"))
{
result.Add(ParseOption(tokenParser));
tokenParser.Move();
}
else
{
result.Add(new ArgCommand(tokenParser.Move()));
}
break;
}
return(result);
}
private IEnumerable <ArgPattern> ParseSequence(ArgTokens tokenParser)
{
var result = new List <ArgPattern>();
while (!new[] { null, "]", ")", "|" }.Contains(tokenParser.Current()))
{
var atom = ParseAtom(tokenParser);
if (tokenParser.Current() == "...")
{
result.Add(new ArgOneOrMore(atom.ToArray()));
tokenParser.Move();
return(result);
}
result.AddRange(atom);
}
return(result);
}
private IEnumerable <ArgPattern> ParseExpression(ArgTokens tokenParser)
{
var seq = ParseSequence(tokenParser);
if (tokenParser.Current() != "|")
{
return(seq);
}
var result = new List <ArgPattern>();
if (seq.Count() > 1)
{
result.Add(new ArgRequired(seq.ToArray()));
}
else
{
result.AddRange(seq);
}
while (tokenParser.Current() == "|")
{
tokenParser.Move();
seq = ParseSequence(tokenParser);
if (seq.Count() > 1)
{
result.Add(new ArgRequired(seq.ToArray()));
}
else
{
result.AddRange(seq);
}
}
result = result.Distinct().ToList();
if (result.Count > 1)
{
return new[] { new ArgEither(result.ToArray()) }
}
;
return(result);
}