[plt-scheme] [redex] language keywords

It would be good to avoid term-let, I think, if you can use things
like 'where' in the reduction relation instead. But we'd probably need
to see an example use if you don't see how to do the transformation.

Robby

On Wed, Jun 2, 2010 at 9:51 PM, Eric Tanter <etanter at dcc.uchile.cl> wrote:
> Yes, I do use term-let and that's (at least up to now) exactly where the
> problem manifests!
>
> Should I be using something else?
>
> -- Éric
>
> On Jun 2, 2010, at 22:40, Casey Klein <clklein at eecs.northwestern.edu> wrote:
>
>> On Wed, Jun 2, 2010 at 9:21 PM, Carl Eastlund <cce at ccs.neu.edu> wrote:
>>>
>>> On Wed, Jun 2, 2010 at 10:15 PM, Casey Klein
>>> <clklein at eecs.northwestern.edu> wrote:
>>>>
>>>> On Wed, Jun 2, 2010 at 9:02 PM, Eric Tanter <etanter at dcc.uchile.cl>
>>>> wrote:
>>>>>>>
>>>>>>> Is there something as simple/direct as the list of keywords in
>>>>>>> syntax-rules/syntax-case?
>>>>>>> If not, any alternative suggestion?
>>>>>>>
>>>>>>> Thanks!
>>>>>>>
>>>>>>> -- Éric
>>>>>>
>>>>>> Take a look at variable-prefix.  In my latest Redex work, variables
>>>>>> all start with x, y, or z, and I just have to avoid any keywords that
>>>>>> start with those.
>>>>>
>>>>> Thanks Carl,
>>>>>
>>>>> I'm using these as well, actually.
>>>>> A problem I have is that, for readability, I have a non-terminal which
>>>>> is define as (x >> x) where '>>' is a keyword. I know I could just use (x x)
>>>>> for exactly the same, but it does enhance readability.
>>>>> The problem is that >> is considered as a pattern variable...
>>>>>
>>>>> with macros I could just say:
>>>>> (syntax-rules (>>)
>>>>>  ((x >> x) ...))
>>>>>
>>>>> Any idea?
>>>>>
>>>>
>>>> I don't follow. The variables in a Redex pattern are always named
>>>> after non-terminals, so I don't see how >> could be treated as a
>>>> pattern variable.
>>>>
>>>> Do you mean that >> matches one of your six classes of variables?
>>>
>>> Is it possible Eric is using one of the forms that match using
>>> syntax-case instead of the Redex pattern matcher?  Do term-let and
>>> where clauses still work that way?
>>
>> Oh, good thinking! term-let uses syntax-case, but where clauses no longer
>> do.
>>
>>> (And if not, Eric, what version of PLT Scheme are you using?)
>>>
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