private static IEnumerable <Pattern> ParseShorts(Tokens tokens, ICollection <Option> options)
{
// shorts ::= '-' ( chars )* [ [ ' ' ] chars ] ;
var token = tokens.Move();
Debug.Assert(token.StartsWith("-") && !token.StartsWith("--"));
var left = token.TrimStart(new[] { '-' });
var parsed = new List <Pattern>();
while (left != "")
{
var shortName = "-" + left[0];
left = left.Substring(1);
var similar = options.Where(o => o.ShortName == shortName).ToList();
Option option = null;
if (similar.Count > 1)
{
throw tokens.CreateException(string.Format("{0} is specified ambiguously {1} times", shortName,
similar.Count));
}
if (similar.Count < 1)
{
option = new Option(shortName, null, 0);
options.Add(option);
if (tokens.ThrowsInputError)
{
option = new Option(shortName, null, 0, new ValueObject(true));
}
}
else
{
// why is copying necessary here?
option = new Option(shortName, similar[0].LongName, similar[0].ArgCount, similar[0].Value);
ValueObject value = null;
if (option.ArgCount != 0)
{
if (left == "")
{
if (tokens.Current() == null || tokens.Current() == "--")
{
throw tokens.CreateException(shortName + " requires argument");
}
value = new ValueObject(tokens.Move());
}
else
{
value = new ValueObject(left);
left = "";
}
}
if (tokens.ThrowsInputError)
{
option.Value = value ?? new ValueObject(true);
}
}
parsed.Add(option);
}
return(parsed);
}
private static IEnumerable <Pattern> ParseAtom(Tokens tokens, ICollection <Option> options)
{
// atom ::= '(' expr ')' | '[' expr ']' | 'options'
// | long | shorts | argument | command ;
var token = tokens.Current();
var result = new List <Pattern>();
switch (token)
{
case "[":
case "(":
{
tokens.Move();
string matching;
if (token == "(")
{
matching = ")";
result.Add(new Required(ParseExpr(tokens, options).ToArray()));
}
else
{
matching = "]";
result.Add(new Optional(ParseExpr(tokens, options).ToArray()));
}
if (tokens.Move() != matching)
{
throw tokens.CreateException("unmatched '" + token + "'");
}
}
break;
case "options":
tokens.Move();
result.Add(new OptionsShortcut());
break;
default:
if (token.StartsWith("--") && token != "--")
{
return(ParseLong(tokens, options));
}
if (token.StartsWith("-") && token != "-" && token != "--")
{
return(ParseShorts(tokens, options));
}
if (token.StartsWith("<") && token.EndsWith(">") || token.All(char.IsUpper))
{
result.Add(new Argument(tokens.Move()));
}
else
{
result.Add(new Command(tokens.Move()));
}
break;
}
return(result);
}
private static IEnumerable <Pattern> ParseLong(Tokens tokens, ICollection <Option> options)
{
// long ::= '--' chars [ ( ' ' | '=' ) chars ] ;
var p = new StringPartition(tokens.Move(), "=");
var longName = p.LeftString;
Debug.Assert(longName.StartsWith("--"));
var value = (p.NoSeparatorFound) ? null : new ValueObject(p.RightString);
var similar = options.Where(o => o.LongName == longName).ToList();
if (tokens.ThrowsInputError && similar.Count == 0)
{
// If not exact match
similar =
options.Where(o => !string.IsNullOrEmpty(o.LongName) && o.LongName.StartsWith(longName)).ToList();
}
if (similar.Count > 1)
{
// Might be simply specified ambiguously 2+ times?
throw tokens.CreateException($"{longName} is not a unique prefix: {string.Join(", ", similar.Select(o => o.LongName))}?");
}
Option option = null;
if (similar.Count < 1)
{
var argCount = p.Separator == "=" ? 1 : 0;
option = new Option(null, longName, argCount);
options.Add(option);
if (tokens.ThrowsInputError)
{
option = new Option(null, longName, argCount, argCount != 0 ? value : new ValueObject(true));
}
}
else
{
option = new Option(similar[0].ShortName, similar[0].LongName, similar[0].ArgCount, similar[0].Value);
if (option.ArgCount == 0)
{
if (value != null)
{
throw tokens.CreateException(option.LongName + " must not have an argument");
}
}
else
{
if (value == null)
{
if (tokens.Current() == null || tokens.Current() == "--")
{
throw tokens.CreateException(option.LongName + " requires an argument");
}
value = new ValueObject(tokens.Move());
}
}
if (tokens.ThrowsInputError)
{
option.Value = value ?? new ValueObject(true);
}
}
return(new[] { option });
}