[R6RS] How to make -> a valid identifier
Marc Feeley
feeley
Wed Jun 8 12:36:49 EDT 2005
On 8-Jun-05, at 12:22 PM, Michael Sperber wrote:
>
> Marc Feeley <feeley at iro.umontreal.ca> writes:
>
>
>> Gambit does as well (i.e. symbol = not a number and not a keyword).
>> The other problem with defining it this way in the R6RS is that
>> future revisions of the standard may have important backward
>> compatibility problems if the syntax of numbers is changed. So
>> although "symbol = not a number and not a keyword" is fine for an
>> implementation of Scheme, it is not OK for the specification of
>> Scheme.
>>
>
> You're right. Given that I screwed up going the fancy route, how
> about
>
> <peculiar identifier> --> + | - | ... | -> <subsequent>*
>
> ?
Well, that would be acceptable, but I'm sure we can come up with
something a bit more general that won't dramatically hinder revisions
of R6RS.
While we're on the subject of symbol syntax, we should discuss a
notation for write/read invariance of symbols. For example, what is
the external representation of (string->symbol "Will \"does\" |not|
(like) this")? I propose:
|Will "does" \|not\| (like) this|
We may also want to prevent "unescaped" symbols from ending (or
beginning) with a colon (so that this notation can be used for
keywords).
Marc
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