[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: why a new lexical form?

This page is part of the web mail archives of SRFI 30 from before July 7th, 2015. The new archives for SRFI 30 contain all messages, not just those from before July 7th, 2015.




On Wed, 5 Jun 2002, Al Petrofsky wrote:

>> From: bear <bear@xxxxxxxxx>
>>
>> Why do we actually need a new lexical form for comments?
>>
>> Can't we just use a syntax definition and say
>>
>> (Comment ...)
>>
>> "expands" to nothing?
>
>I sometimes use ' as a way to comment out multiline commands and
>definitions.
>
>However, it is more useful to be able to comment at the token level:
>
>  (define stuff
>    '(foo
>      bar
>  #| FIXME: These two cause crashes for some reason  -APP
>      baz
>      quux
>  |#
>      zork))
>
>-al

I'm not getting it.  How is this different from

   (define stuff
      '(foo
        bar
     (Comment FIXME: These two cause crashes for some reason -APP
        baz
        quux
     )
        zork))


I bring this up because anything that requires new tokens
to be recognized by the lexer is inherently nonportable.
It is either "there" or "not there" in a given system, and
there's not much you can do about it.

One thing that argues *against* my paren-delimited
alternative is the effects of autoindentation on it
potentially disrupting the cognitive flow of the
code.


			Bear