public TokenStream(IEnumerable<Token> tokens)
{
var enumerator = tokens.GetEnumerator();
current = enumerator.MoveNext()
? enumerator.Current
: new Token(TokenKind.EndOfInput, new Position(1, 1), "");
rest = new Lazy<TokenStream>(() => LazyAdvance(enumerator));
}
private static double ParseAmount(Token number)
{
var literal = number.Literal;
var match = TimePartRegex.Match(literal);
if (match.Success)
{
var whole = Int32.Parse(match.Groups["whole"].Value);
var fraction = Int32.Parse(match.Groups["fraction"].Value);
return whole + (fraction / 60d);
}
return Double.Parse(literal, NumberStyles.Any);
}
public bool TryMatch(Text text, out Token token)
{
var match = Match(text);
if (match.Success)
{
token = new Token(this, text.Position, match.Value);
return true;
}
token = null;
return false;
}
public void ImprovingDefaultMessagesWithAKnownExpectation()
{
var labeled = Label(AB, "'A' followed by 'B'");
//When p succeeds after consuming input, Label(p) is the same as p.
AB.Parses(Tokenize("AB")).WithNoMessage().WithValue(Literal("AB"));
labeled.Parses(Tokenize("AB")).WithNoMessage().WithValue(Literal("AB"));
//When p fails after consuming input, Label(p) is the same as p.
AB.FailsToParse(Tokenize("A!")).LeavingUnparsedTokens("!").WithMessage("(1, 2): B expected");
labeled.FailsToParse(Tokenize("A!")).LeavingUnparsedTokens("!").WithMessage("(1, 2): B expected");
//When p succeeds but does not consume input, Label(p) still succeeds but the potential error is included.
var succeedWithoutConsuming = new Token(null, null, "$").SucceedWithThisValue();
succeedWithoutConsuming
.PartiallyParses(Tokenize("!"))
.LeavingUnparsedTokens("!")
.WithNoMessage()
.WithValue(Literal("$"));
Label(succeedWithoutConsuming, "nothing")
.PartiallyParses(Tokenize("!"))
.LeavingUnparsedTokens("!")
.WithMessage("(1, 1): nothing expected")
.WithValue(Literal("$"));
//When p fails but does not consume input, Label(p) fails with the given expectation.
AB.FailsToParse(Tokenize("!")).LeavingUnparsedTokens("!").WithMessage("(1, 1): A expected");
labeled.FailsToParse(Tokenize("!")).LeavingUnparsedTokens("!").WithMessage("(1, 1): 'A' followed by 'B' expected");
}
private TokenStream(Token current)
{
this.current = current;
rest = new Lazy<TokenStream>(() => this);
}
private TokenStream(Token current, IEnumerator<Token> enumerator)
{
this.current = current;
rest = new Lazy<TokenStream>(() => LazyAdvance(enumerator));
}