Speaking of n+k patterns, did anyone ever answer this question?
> Date: Wed, 14 Apr 1993 11:24:54 +
> From: [EMAIL PROTECTED]
> Subject: Successor patterns in bindings
> To: Multiple recipients of list HASKLD-L <[EMAIL PROTECTED]>
>
> I'm puzzled by a bit of the Haskell 1.2 repo
You are quite right. I'd forgotten about local rebinding,
because I feel that all local rebinding should be disallowed.
Anyone want to start a movement to eliminate local
rebinding? (1/2 :-) Cheers, -- P
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>From [EMAIL PROTECTED] Tue May 18 14:56:37 1993
Da
> Both (>=) and (-) belong to classes defined in PreludeCore,
> and hence cannot be rebound. This was a deliberate decision,
> made in order to turn your point into a non-problem.
It's true that things from PreludeCore cannot be rebound on the top level,
but they can be rebound locally. So the
Phil wrote:
> Both (>=) and (-) belong to classes defined in PreludeCore,
> and hence cannot be rebound. This was a deliberate decision,
> made in order to turn your point into a non-problem.
>
> Long live (n+k)! -- P
The Report tries to handle this by "always implicitly importing"
Pr
Phil Wadler says:
You are quite right. I'd forgotten about local rebinding,
because I feel that all local rebinding should be disallowed.
Anyone want to start a movement to eliminate local
rebinding? (1/2 :-) Cheers, -- P
And *I* think we should stop using names altogether and p
> More questions along the same lines as for n+k:
>
> Does == in the pattern match translation refer to == in PreludeCore?
>
> Does negate in the translation of -e refer to negate in PreludeCore?
All identifiers used in explicit translations refer to those
from the Prelude.
Kevin
Lennart Augustsson <[EMAIL PROTECTED]> writes:
> PS. I'd like to start the "Ban n+k patterns"-movement, any followers?
Count on me! I guess this makes it an organized movement ... two persons
(movement) that know about each other (organized).
Cheers,
Karl-Filip
I like the capability to redefine syntax.
For example, I would like to be able to define syntax that looks like
EBNF when writing parsers. I would like to be able to write
E = T {(`+`|`-`) T}
rather than
e = concat1 (t,zeroOrMore (concat2 (alternative (lit '+',lit '-'),t)))
Of course infix
The Haskell Committee was well aware of the problem of name
capture in syntactic expansions. We discussed various solutions
and opted for the simplest (if not most formal): whenever a
name freshly appears on the right side of a translation, add
a comment that says where it came from. If you
Both (>=) and (-) belong to classes defined in PreludeCore,
and hence cannot be rebound. This was a deliberate decision,
made in order to turn your point into a non-problem.
Long live (n+k)! -- P
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>From [EMAIL PROTECTED] Mon May 17 21:33:41 1993
From: Lenna
|Another question along the same lines: What if (+) has been rebound?
|Are n+k patterns still allowed?
|
|-- Lennart
The answer should be that n+k patterns are still allowed, but (+), (-),
and (>=) from PreludeCore are used in the translation.
--Joe
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