#13178: problem with newlines in gap eval
------------------------------+---------------------------------------------
Reporter: kcrisman | Owner: was
Type: defect | Status: new
Priority: major | Milestone: sage-5.2
Component: interfaces | Resolution:
Keywords: gap | Work issues:
Report Upstream: N/A | Reviewers:
Authors: | Merged in:
Dependencies: | Stopgaps:
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Comment (by iandrus):
There are two ways that sage sends data to GAP. The first is to send it
line by line, and the second is to send it via a file. This last is used
when there is a lot of data because, IIRC, it's faster. However, this
messes up the use of stdout e.g. Print. So what's happening is if the
input is long enough, it goes to a file. That's why removing some of the
prints makes a difference. You can also get the same effect by adding a
bunch of spaces in the middle (they are stripped from the beginning and
the end).
One way around this is to use
{{{
gap.eval(...., allow_use_file=False)
}}}
which allows you to see that this is in fact the cause of the problem.
The second method is to change the cutoff (default is 100)
{{{
gap._eval_using_file_cutoff = 1000
}}}
or disable it entirely
{{{
self._eval_using_file_cutoff = None
}}}
You can set it in `~/.sage/init.sage` to make it "permanent".
As for a truly permanent solution, we could try disabling it if we see a
function that prints to stdout like Print or Display, but it wouldn't work
for custom functions. I don't think there is a way around this based on
how GAP is currently written (except not using a file), but I could be
wrong.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/13178#comment:3>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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