ChrisK wrote:
Andrew Coppin wrote:
Anybody want to explain to me why this doesn't work?
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Loading package base ... linking ... done. Prelude> :m Text.ParserCombinators.Parsec Prelude Text.ParserCombinators.Parsec> parseTest (endBy anyToken (char '#')) "abc#" Loading package parsec-2.0 ... linking ... done. parse error at (line 1, column 1): unexpected "b" expecting "#"
anyToken is singular: it accepts a single token, in this case 'a'.
Then endBy expects (char '#') to match and reads 'b' instead and gives the error message.
So using (many anyToken) gets further:
Prelude Text.ParserCombinators.Parsec> parseTest (endBy (many anyToken) (char '#')) "abc#" Loading package parsec-2.0 ... linking ... done. parse error at (line 1, column 1): unexpected end of input expecting "#" Prelude Text.ParserCombinators.Parsec> parseTe
Here (many anyToken) reads all of "abc#" and then endBy wants to read (char '#') and get the end of input instead.
So the working version of endBy is thus:
Prelude Text.ParserCombinators.Parsec> parseTest (endBy (many (noneOf "#")) (char '#')) "abc#" ["abc"]
Or you may need to not use endBy...
But hang on a minute... "many" parses 0 or more occurrances of an item. "sepBy" parses 0 or more occurrances of an item, seperated by another item. "endBy" parses 0 or more occurrances of an item, terminated by another item. "sepEndBy" parses 0 or more occurrances of an item, seperated *and* terminated by another item. ...except that "endBy" doesn't seem to be working right. :-S