ACE.Combinators

Parser combinators.

Documentation

string :: Stream s m Token => Text -> ParsecT s u m Text

Match a word with the given string.

genitive :: Stream s m Token => ParsecT s u m Bool

Match a Saxon genitive.

number :: Stream s m Token => ParsecT s u m Integer

Match a word with the given string.

quoted :: Stream s m Token => ParsecT s u m Text

Quoted string.

comma :: Stream s m Token => ParsecT s u m ()

A comma.

period :: Stream s m Token => ParsecT s u m ()

A period.

strings :: Stream s m Token => [Text] -> ParsecT s u m ()

Try to match all the given strings, or none at all.

satisfy :: Stream s m Token => (Token -> Maybe a) -> ParsecT s u m a

Satisfy the given predicate from the token stream.

anyToken :: Stream s m Token => ParsecT s u m Token

The parser anyToken accepts any kind of token. It is for example used to implement eof. Returns the accepted token.

tokenString :: Token -> [Char]

Make a string out of the token, for error message purposes.

tokenPosition :: SourcePos -> Token -> t -> SourcePos

Update the position by the token.

notFollowedBy :: Stream s m Token => ParsecT s u m Token -> ParsecT s u m ()

notFollowedBy p only succeeds when parser p fails. This parser does not consume any input. This parser can be used to implement the 'longest match' rule. For example, when recognizing keywords (for example let), we want to make sure that a keyword is not followed by a legal identifier character, in which case the keyword is actually an identifier (for example lets). We can program this behaviour as follows:

  keywordLet  = try (do{ string "let"
                       ; notFollowedBy alphaNum
                       })

eof :: Stream s m Token => ParsecT s u m ()

This parser only succeeds at the end of the input. This is not a primitive parser but it is defined using notFollowedBy.

  eof  = notFollowedBy anyToken <?> "end of input"