Expression parser just doesn't work at all

[konn]

Expression parser just doesn't work at all

[ekmett]

I'm ringing @nwf and @bartavelle as they seem to be the ones who last touched this.

Any thoughts on what happened, guys?

[bartavelle]

I can't really check as I am on holidays but the change I preformed was to
revert it back to an implementation identical to that in parsec
Le 1 nov. 2013 01:38, "Edward Kmett" [email protected] a écrit :

I'm ringing @nwf https://github.com/nwf and @bartavellehttps://github.com/bartavelleas they seem to be the ones who last touched this.

Any thoughts on what happened, guys?

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/24#issuecomment-27540597
.

[nwf]

git bisect traced this down to 62941f5; in particular, the offending change is

-              ambiguous assoc op= try $ op *> fail ("ambiguous use of a " ++ assoc ++ " associative operator")
+              ambiguous assoc op= op *> empty <?> ("ambiguous use of a " ++ assoc ++ "-associative operator")

Putting the "try $" back causes this example to work, but that may not be the right fix. Thoughts?

[ekmett]

/cc @blamario

[blamario]

I did comment at the time that I hadn't properly tested the applicative version of the expression builder. In fact, what testing I've done was with uu-parsinglib which doesn't have the try operator. So putting back the try $ seems to be proper.

[ekmett]

Sounds good. I'll make the change.

[ekmett]

Fixed.