Re: bug#33403: Data length limit in Guile/Geiser/Scheme evaluation

["Jose A. Ortega Ruiz" <jao-mXXj517/zsQ@public.gmane.org>]

On Fri, Nov 16 2018, Neil Jerram wrote:

> Neil Jerram <neil-mq78CtbEgnGjF4gvJNWmbtHuzzzSOjJt@public.gmane.org> writes:
>
>> Mark H Weaver <mhw-StlzRsPvAncdnm+yROfE0A@public.gmane.org> writes:
>>
>>> This is a documented limitation in Linux's terminal handling when in
>>> canonical mode.  See the termios(3) man page, which includes this text:
>>>
>>>    Canonical and noncanonical mode
>>>        
>>>        The setting of the ICANON canon flag in c_lflag determines
>>>        whether the terminal is operating in canonical mode (ICANON set)
>>>        or noncanonical mode (ICANON unset).  By default, ICANON is set.
>> [...]
>>>        * The maximum line length is 4096 chars (including the
>>>          terminating newline character); lines longer than 4096 chars
>>>          are truncated.  After 4095 characters, input processing (e.g.,
>>>          ISIG and ECHO* processing) continues, but any input data after
>>>          4095 characters up to (but not including) any terminating
>>>          newline is discarded.  This ensures that the terminal can
>>>          always receive more input until at least one line can be read.
>>>
>>> Note that last item above.
>>
>> Awesome; thank you Mark.
>>
>> So possibly this limit can be removed, in my Org/Geiser context, by
>> evaluating (system* "stty" "-icanon") when initializing the Geiser-Guile
>> connection.  I'll try that.  Will the terminal that that 'stty' sees be
>> the same as Guile's stdin?
>>
>> Jao, if that works, I wonder if it should be the default for Geiser?  It
>> appears to me that Geiser shouldn't ever need the features of canonical
>> mode.  Is that right?
>>
>> Anyway, I'll see first if the stty call is effective.
>
> Yes, with this in my ~/.guile-geiser -
>
> (system* "stty" "-icanon")
>
> - I can do evaluations past the 4K line length limit, and the Org-driven
> problem that I first reported [1] has disappeared.

Ah, system* is a scheme call! So yeah, maybe we could add that call to
Geiser's guile initialization... i don't really see how that would cause
any problem elsewhere.

> Thanks to Nicolas, Jao and Mark for your help in understanding this.

And thanks to Nicolas, Mark and you for yours :)

Cheers,
jao
-- 
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