[Haskell-cafe] map (-2) [1..5]

John Meacham john at repetae.net
Thu Aug 17 13:56:06 EDT 2006

On Thu, Aug 17, 2006 at 11:14:32AM +0100, Brian Hulley wrote:
> I'd have thought it would have been simpler to just make the rule that -2 
> (no spaces between '-' and '2') would be a single lexeme, and then people 
> could just use (negate x) or (0 - x) instead of having a special rule and a 
> whole lot of confusion just for one arithmetic operator, which is never 
> actually needed in the first place (just as we don't need /x because it is 
> simple enough to write 1/x).

yes yes yes. the current handling of - is a huge wart that needs to be
excised. I run into issues with it still and grumble to myself, and have
been programming haskell for years. '-' should be part of the numerical
lexical syntax and not be special in any other way. we alreday have .
being treated as lexically part of a number, and 'e', and 'x' in certain
cases, so why the special anoying case for '-'?

> I see with great disappointment that Haskell' Trac ticket#50 [1] looks as 
> if it will not be accepted [2] so we're likely to be stuck with this for 
> years to come...
> [1] http://hackage.haskell.org/trac/haskell-prime/ticket/50
> [2] http://hackage.haskell.org/trac/haskell-prime/wiki/StrawPoll-2

I hope this changes.


John Meacham - ⑆repetae.net⑆john⑈

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