Łukasz Stelmach writes:
> Dan Davison writes:
>
>> Łukasz Stelmach writes:
>>> I am not sure I will be able to spend some time on this so I'll share my
>>> observation with you. org-babel-perl can't cope with perl formats, with
>>> their endings to be precise. A format is defined by:
>>>
>>> format FORMAT_NAME =
>>> body of the format
>>> .
>>>
>>> The problem is that formats *must* and with a single solitary dot or, to
>>> be precise "\n.\n" sequence. org-babel-perl doesn't care about it and
>>> puts "\t" befor the dot.
>>
>> Could you post an example? I don't believe we insert tab
>> characters. I've never used a perl format before, but I just tried it
>> and it seemed to work OK with C-c C-c:
>>
>> #+begin_src perl
>> format STDOUT =
>> @<< @|| @>>
>> "left", "middle", "right"
>> .
>> write ;
>> #+end_src
>>
>> #+results:
>> : leftmiddleright
>
> With the very same code i get
>
> Format not terminated at - line 11, at end of line
> syntax error at - line 11, at EOF
> Execution of - aborted due to compilation errors.
Oops. Sorry Łukasz, my mistake.
You are of course right, we were adding indentation to perl code
(apparently I started with a copy of org-babel-python.el when I wrote
org-babel-perl.el). That is fixed now.
We got different results because I had set perl to :results output by
default. For this particular block, you will also want to use
:results output (see below).
You pointed out that
>
> while strace shows the code being wrapped
>
> write(9, "\nsub main {\n\tformat STDOUT =\n\t@<< @||
> @>>\n\t\"left\", \"middle\", \"right\"\n\t.\n\twrite ;\n...@r =
> main;\nopen(o, \">/tmp/perl-functional-results17170oCG\");\nprint o
> join(\"\\n\", @r), \"\\n\"", 184) = 184
>
> inside something really odd:
>
> sub main {
> format STDOUT =
> @<< @|| @>>
> "left", "middle", "right"
> .
> write ;
> }
> @r = main;
> open(o, ">/tmp/perl-functional-results17170oCG");
> print o join("\n", @r), "\n"
Babel has two basic modes of execution:
:results value :: The default, you get the value of the last expression,
interpreted as a list/table if possible.
:results output :: You get stdout
The wrapping-in-function-body stuff only happens with :results value.
So by default, with the block above, you will get the counterintuitive outcome:
#+results:
| 1 |
| 1 |
The default outcome here is fairly baffling, and I imagine that perl
users are often going to want the contents of stdout. This can be done
globally with
(setq org-babel-default-header-args:perl '((:results . "output")))
The trouble with that is that perl blocks will not communicate nicely
with other blocks:
#+source: a-number
#+begin_src perl :results value
4
#+end_src
#+begin_src emacs-lisp :var i=a-number()
(+ i 1)
#+end_src
#+results:
: 5
With :results output on the perl block, we get a
Wrong type argument: number-or-marker-p, ""
because the perl block returns textual output rather than interpreting
the result as numeric.
Dan
>
>> Incidentally, do you know the variable org-src-preserve-indentation?
>> When I first read your email I thought that would be the answer. In fact
>> it doesn't seem to be relevant, but I thought I would mention it anyway.
>
> Unfortunately it doesn't make any difference.
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