Re: r6rs incompatibilities

[Ludovic Courtès]

Hi,

Andy Wingo <address@hidden> writes:

> On Wed 26 May 2010 15:02, Julian Graham <address@hidden> writes:
>
>>>> We could make this more general, as the r7 committees are wont to do: if
>>>> #! is followed by whitespace or /, then read as a block comment;
>>>> otherwise read one token. In our case, we would read #!foo as #:foo. I
>>>> don't think this change would affect anyone. What do you think?
>>>
>>> Note that there are a couple of other #! constructs being considered for
>>> scheme 7, for example to control case folding. It seems more or less
>>> sensible. Perhaps we should read these as directives, and not as datums
>>> at all.
>>>
>>> There is also the possibility of introducing a reader option for this
>>> behavior.
>>
>> Any chance we could go with my (admittedly sloppy) approach (or
>> something equally as quick) in the short term, and then, as they say
>> in the 'biz, "iterate?"  The above sounds sweet, but it seems like
>> it'd make more sense to tackle those things post-2.0.
>
> Heh, sure. But don't make it return SCM_UNSPECIFIED, please; make it
> treat #!r6rs as a comment. See
> http://www.r6rs.org/final/html/r6rs/r6rs-Z-H-7.html#node_sec_4.2.3.

Functions that read comments all return ‘SCM_UNSPECIFIED’, which allows
them to be distinguished by the main loop.

Thanks,
Ludo’.