/// <summary>
/// Constructs a parser that returns the <see cref="ITextSpan{T}"/> of the parsed value.
/// </summary>
/// <typeparam name="T">The result type of the given parser.</typeparam>
/// <param name="parser">The parser to wrap.</param>
/// <returns>A parser for the text span of the given parser.</returns>
public static Parser <ITextSpan <T> > Span <T>(this Parser <T> parser)
{
if (parser == null)
{
throw new ArgumentNullException(nameof(parser));
}
return(i =>
{
var r = parser(i);
if (r.WasSuccessful)
{
var span = new TextSpan <T>
{
Value = r.Value,
Start = Position.FromInput(i),
End = Position.FromInput(r.Remainder),
Length = r.Remainder.Position - i.Position,
};
return Result.Success(span, r.Remainder);
}
return Result.Failure <ITextSpan <T> >(r.Remainder, r.Message, r.Expectations);
});
}
/// <summary>
/// Parses the specified input string.
/// </summary>
/// <typeparam name="T">The type of the result.</typeparam>
/// <param name="parser">The parser.</param>
/// <param name="input">The input.</param>
/// <returns>The result of the parser.</returns>
/// <exception cref="Sprache.ParseException">It contains the details of the parsing error.</exception>
public static T Parse <T>(this Parser <T> parser, string input)
{
if (parser == null)
{
throw new ArgumentNullException(nameof(parser));
}
if (input == null)
{
throw new ArgumentNullException(nameof(input));
}
var result = parser.TryParse(input);
if (result.WasSuccessful)
{
return(result.Value);
}
throw new ParseException(result.ToString(), Position.FromInput(result.Remainder));
}