prefix minus and infix resolution
Christian Maeder
Christian.Maeder at dfki.de
Wed Jul 14 08:22:48 EDT 2010
Atze Dijkstra schrieb:
> Hi,
>
> I prefer the simplicity of http://hackage.haskell.org/trac/haskell-prime/wiki/NegationBindsTightly over the more involved proposal.
It's a simple design choice but hard to put into practice for
compatibility reasons.
It is an old design choice between fortran and C style (earlier taken
for Haskell) http://www.obliquity.com/computer/fortran/operate.html
> I'd gladly pay the price of adding some parenthesis to force "- x ^ 2" to "- (x ^ 2)".
fortran and python have infix power operators that bind more tightly
than unary minus. The mathematical unusual silent interpretation of "- x
^ 2" as "(- x) ^ 2" is the problem (and not that I better should write
"- (x ^ 2)").
Other languages i.e. C do not have a power operator!
Does "- pow x 2" read better? Leave it to users to define "^" and "**"
as they like?
Cheers Christian
This is also much more clearer, less dependent on context info (i.e.
the fixity of other operators), thus understandable without inspecting
the definition of ^ in some other module, and thus also easier to
explain (to students), and thus lessening the steepness of Haskells
learning curve somewhat.
>
> cheers,
>
> On 13 Jul, 2010, at 18:38 , Christian Maeder wrote:
>
>> Hi,
>>
>> I'm asking for support of:
>>
>> http://hackage.haskell.org/trac/haskell-prime/wiki/PrefixMinusResolution
>>
>> Cheers Christian
>>
>> Simon Marlow schrieb:
>>> BTW, here's a related proposal made by Simon PJ earlier this year:
>>>
>>> http://hackage.haskell.org/trac/haskell-prime/wiki/NegationBindsTightly
>>>
>>> please consider merging the proposals, or at least clearly identifying
>>> the differences, if any.
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>
>
> - Atze -
>
> Atze Dijkstra, Department of Information and Computing Sciences. /|\
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