[plt-dev] syntax/module-reader and #%module-begin

From: Carl Eastlund (carl.eastlund at gmail.com)
Date: Tue Dec 1 13:51:33 EST 2009

On Tue, Dec 1, 2009 at 1:10 PM, Stevie Strickland <sstrickl at ccs.neu.edu> wrote:
> On Dec 1, 2009, at 12:06 PM, Sam TH wrote:
>>>>> The reason I've asked this is that a reader that adds
>>>>> `#%module-begin' will be broken if it's added by
>>>>> `syntax/module-reader' unconditionally.
>>>> That is a potential problem.  Are there any languages that do that
>>>> right now?
>>> I don't know -- that's (part of) my question.
>> If there are, and they're hard to fix (ie, on planet), then I think we
>> should adopt your suggestion.  Otherwise, we should keep the rule
>> simple.
> No language in the PLT Scheme code base does this.  Unfortunately the first PLaneT
> language I looked at, Jay's datalog package, does.  Since I'm already 1/1 for PLaneT
> packages adding them, I'm going to stop looking there and just go ahead and change the
> code to only add the #%module-begin if it's not a single expression that already has one.

It is probably worth documenting (a) that syntax/module-reader does
this, and (b) that it is a deprecated practice; i.e. that future
language readers should always leave the #%module-begin up to
syntax/module-reader.  Going forward, we should really pick one way
and stick with it.


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