Re: [O] R code block produces only partial output

[Nick Dokos]

John Hendy <address@hidden> writes:

> On Tue, Aug 5, 2014 at 2:02 PM, Eric Schulte <address@hidden> wrote:
>> Charles Berry <address@hidden> writes:
>>
>>> Eric Schulte <schulte.eric <at> gmail.com> writes:
>
> [snip]
>
>>> Eric,
>>>
>>> As noted by Andreas and John this is a problem for session output.
>>>
>>> org-babel-R-evaluate-session uses
>>>
>>>  (string-match "^\\([ ]*[>+\\.][ ]?\\)+\\([[0-9]+\\|[ ]\\)" line)
>>>
>>> to find the start of R output in the session.
>>>
>>> This does not match the `          0', but matches the `         .6'
>>> in the output you show above, so if that had been in a session, all the
>>> output up to and including the '.' before the '6' would be clipped
>>> by the following
>>>
>>>   (substring line (match-end 1))
>>>
>>>
>>> as Andreas output showed.
>>>
>>> Deleting the "\\." fixes Andreas case, but what are the circumstances
>>> requiring the  "\\." ?
>>>
>>
>> I don't know.
>
> I'm not sure either, but was curious if someone could translate the
> regex into "plain language." Maybe I could observe some typical
> outputs and chime in since I use R regularly? From noob-level regex
> stuff, it's looking for a new line followed by some number of spaces,
> a ">" and at least one period and numbers?
>

It says[fn:1]

^                          anchor the match at the beginning of the line

\\([ ]*[>+\\.][ ]?\\)+     match any number of spaces followed by one of
                           the three characters >, + or . (a literal
                           period) followed by 0 or 1 space. If there is
                           a match, remember what is matched as group 1
                           (that's what the escaped parentheses
                           \\(...\\) do). Match one or more of these
                           (that's what the + at the end does).

\\([[0-9]+\\|[ ]\\)        match either an emtpy space or a sequence
                           of one or more of the characters [ or 0-9
                           i.e. an opening square bracket or a digit.
                           remember what is matched as group 2.

The latter will match [0[1[2[3 e.g. which does not sound right.

The best way to find out what a regexp will match is to start with
a buffer containing example strings that you are trying to match
and example string that you are trying *not* to match, then invoke

    M-x regexp-builder

and paste the regexp inside the empty set of quotes, then check the highligted
matches to see if they agree with your expectations.

Footnotes:

[fn:1] Crossing fingers and toes, hoping I've got it right...

-- 
Nick