[Haskell-cafe] Re: Float instance of 'read'

Mauricio briqueabraque at yahoo.com
Wed Sep 17 11:20:04 EDT 2008

>> Do you think 'read' (actually,
>> 'readsPrec'?) could be made to also
>> read the international convention
>> (ie., read "1,5" would also work
>> besides read "1.5")? I'm happy to
>> finaly use a language where I can
>> use words of my language to name
>> variables, so I wonder if we could
>> also make that step.
> The purpose of 'read' is to read haskell notation, not to read 
> locally-sensitive notation.
> So the right question to ask is "should we change haskell's lexical 
> syntax to support locally-sensitive number notation".
> IMO, the answer is no. (...)

Agree about the answer, not about the question. The
correct one would be "is it possible to change haskell
syntax to support the international notation (not any
locally sensitive one) for decimal real numbers? Would
a change in 'read' be a good first step?"

I know this looks difficult, but I'm sure it deserves at
least some thinking. We have previous examples for
less important issues: ghc does accept Windows end
of line conventions, the minus and sign needs special
syntax, and '.' can be used as decimal separator even
if it's use as function notation.


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