I'd just like to remark that I think the current behaviour is the
right thing to do with respect to -x^2. Negation is related to
addition and so should always bind more weakly than multiplicative
operations.
- Cale
On 2010-07-15, at 4:31, Christian Maeder
Hi Atze,
I share your desire for simplicity. In fact, I think my proposal is simpler than the existing ones of hugs, ghc, nhc98 and the language descriptions (98, 2010), although it's basically a matter of tuning.
Layout and the type system are far more involving and should not interfere with fixity resolution!
Simon said somewhere that fixity resolution takes basically 12 lines of haskell code. (My algorithm has 40 but shorter ones.)
Furthermore, fixity resolution is a nice subject for teaching in conjunction with expression evaluation.
I added a remark to the end of http://hackage.haskell.org/trac/haskell-prime/wiki/PrefixMinusResolution about rejecting prefix minus applications that do not bind tightly. It would use the same resolution algorithm with one modified line.
It says: reject "- 1 ^ 2" always without parens in order to avoid the too simple (wrong) resolution as "(- 1) ^ 2".
C.