A) You can't, the way haskell-src-exts is built. You need to specify the %partial directives in the happy grammar, so without editing haskell-src-exts there's no way you could tack on partiality to the existing parsing primitives.

B) It's a great feature request (to the point where I wonder why I haven't thought of it before), that should be quite easy to implement. I already export a partial parser for top-of-file pragmas, there's no reason why I couldn't export partial parsers for all the other entry points as well. I hope I can implement it shortly, but if you want it really fast and certain - patches are most welcome!

On Mon, Mar 14, 2011 at 6:55 PM, J. Waldmann <waldmann@imn.htwk-leipzig.de> wrote:

Hi.

I want to use parsers from haskell-src-exts as sub-parsers,
which does not seem to work since they insist on consuming the input completely.

I would need them to parse a maximal prefix,
and return the (unconsumed) rest of input as well
(cf.
http://hackage.haskell.org/packages/archive/parsec/3.1.1/doc/html/Text-Parsec-Prim.html#v:getInput
)

I figure that happy has the %partial directive for that, but the description
http://www.haskell.org/happy/doc/html/sec-directives.html#sec-partial-parsers
does not really tell me how to obtain the rest of the input.

Any hints (or code samples) appreciated. Thanks - J.W.

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