[Haskell-cafe] Proposal: Shorter Import Syntax

Anthony Cowley acowley at seas.upenn.edu
Fri Jun 5 22:09:46 UTC 2015

On Fri, Jun 5, 2015 at 5:55 PM, Sven Panne <svenpanne at gmail.com> wrote:
> 2015-06-05 7:52 GMT+02:00 Malcolm Wallace <malcolm.wallace at me.com>:
>> [...] I think there is a burden on the proposer to demonstrate a decent
>> power-to-weight ratio for the change, and saving a few characters at the
>> expense of introducing considerable confusion just does not seem right to
>> me.  "The new syntax does not let us do anything we cannot do now."  On the
>> other hand, I could imagine a different import system altogether being
>> attractive, perhaps a higher-order one like ML modules, although someone
>> would have to flesh out the details.
> Just another +1 to everything Malcolm wrote: IMHO the proposal is just
> bikeshedding and doesn't really buy us much. Saving a few keystrokes is not
> a good argument when it comes to language design, see e.g. Perl or the
> latest additions to JavaScript. The current syntax might be a bit verbose,
> but it's easily comprehensible, and the proposal is a bit confusing. I would
> really welcome some more powerful module system, e.g. in the spirit of
> ML/OCaml, but not some ad hoc changes to the current one.
> Regarding the grep on Stackage: Here transitive dependencies should be taken
> into account, so I guess the overall breakage would be much, much higher. A
> per-module/package grep is basically meaningless.
> Finally: Enabling anything by default what might break something is a total
> no-go, *unless* everybody agrees that the current state of affairs is broken
> and the new state is much better. Both doesn't hold here. Enabling some
> things behind a flag/pragma is OK, time will then tell if the idea is good
> or not.
> Just my 2c,
>    S.

This was stated unambiguously in the proposal and several times since
then, but, just to clarify: *there is no possible breakage from this
change*. In other words, the percentage of Haskell programs that will
break will not be "much, much higher." It will be 0%.

Again: nothing whatsoever *can* break. The proposed syntax is
currently a parse error. Please let me know how the proposal or the
thread is confusing on this issue so I can clarify it and prevent
people from doom and gloom prognostications.


P.S. Nothing will break.

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