[R] R-code in html help pages: syntax highlighting

Wacek Kusnierczyk Waclaw.Marcin.Kusnierczyk at idi.ntnu.no
Tue Mar 17 09:27:52 CET 2009


Romain Francois wrote:
> Duncan Murdoch wrote:
>
> That is an issue. I guess I will fall back on what the parser says and
> infer on the scoping. Within the lines below, mean would be different
> each time
>
> mean( 1:10 )
> lapply( 1:10, mean)
> mean <- (1+4) / 2
> lapply( list( mean, median), function( f ) f( 1:10) )
> { mean <- median; mean( 1:10 ) }
>
>> So if you've got high standards, it's probably quite hard.  On the
>> other hand, if you're willing to accept the usual sort of errors that
>> syntax highlighters make, it's not so bad, but not trivial.
>

it would be good to know what you mean by 'errors'.  syntax highlighters
are, in principle, *syntax* highlighters.  in the example above, the
first and sixth occurrences of 'mean' are in the operator position, the
others are not -- would it be *syntactically* inappropriate to
color-code the former in one way, and the latter in another?  why should
a *syntax* highlighter care about what's the object referred to by
'mean' in this or other context?

otherwise, it would certainly be fun to have a semantic highlighter for r.

(..)

>
>
>> (I'd guess it'll be fast enough: Brian Ripley reported that all the R
>> code he wrote for conversions in R-devel was faster than the Perl
>> code it was replacing.)

the 'benchmark' you are talking about is only as good as the perl
scripts were.  i have had a look at a couple of perl scripts in the r
sources, and it seemed like there was quite some space for improvement.


vQ




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