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 <christian.mae...@dfki.de> wrote:

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.
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