[parenscript-devel] Skipping null returns at the top level.

[szergling]

On 2/16/10, szergling <senatorzergling at gmail.com> wrote:
> On 2/13/10, Vladimir Sedach <vsedach at gmail.com> wrote:
>> Hi Yong,
>>
>> On what forms does ps-compile-stream fail? I'm using this as a test:
>>
>> (with-input-from-string (s "(progn
>>     (defmacro macro-null-toplevel ()
>>       nil)
>>     (macro-null-toplevel))")
>>       (ps-compile-stream s))
>>
>> Vladimir
>>
>
> Hi Vladimir,
>
> You are quite right. I am mistaken. Sorry for the noise.
>
> I'm guessing that I had been misled by stale fasls. My best guess at
> the moment is that it is compilation-interface.fasl that depends on
> special-forms but comes before it in the .asd file. I cannot
> reproduce this since I've wiped my old directory. Could that have
> happened?
>
> Yong.

I'm quite confused now, so it's probably best to get independent
verification. Here's the form I'm interested in. It's actually two
forms (as when read in via ps-compile-file):

(with-input-from-string (s "
    (defmacro macro-null-toplevel ()
      nil)
    (macro-null-toplevel)")
  (ps-compile-stream s))
==> "null"

I'm hoping to get nothing here, as in Vladimir's original progn form.

Compare

(with-input-from-string (s "(progn
    (defmacro macro-null-toplevel ()
      nil)
    (macro-null-toplevel))")
  (ps-compile-stream s))
==> ""

So perhaps I did see the null producing behaviour originally,
after all  :)


Yong.