Re: [R] R-code in html help pages: syntax highlighting
Duncan Murdoch wrote:
On 16/03/2009 5:06 PM, Romain Francois wrote:
hadley wickham wrote:
It would be pretty easy to use the output from the R parser (which
is never
wrong, is it?), and dump some markup out of it. For example the
showTree
function in codetools dumps an R expression as Lisp, this is not
too far
from generating html, or any other markup.
As this sounds like fun, I'll volunteer to do something about this.
Another
advantage is that we can imagine to plug hyperlinks in R code that
lives in
html help pages.
This also sounds like a good idea for a google summer of code project
- that way you might be able to get a student to give you a hand as
well.
Hadley
That did cross my mind earlier this evening, it just seems a bit too
easy to last all summer, but maybe I am missing something difficult.
I will start to play with this over the next few days, and make up my
mind.
It depends on your standards. You said you want R to parse the code
in the Rd file. That's going to be hard, because Rd files contain
something that is only R-like, as far as the parser is concerned.
You'll need to convert it into R code before you can pass it to the R
parser.
I would assume this would be outsourced to the experimental parse_Rd
function
And then there's the question of scoping, which gets into the
evaluator, not just the parser. (The parser only recognizes mean as
an identifier; it's the evaluator that decides whether it's the
function in the base package or a local variable.)
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.
There is probably some middle ground between the job an highlighter
would do, and the way the R evaluator would think the expression
eventually. Given that this is more a nice to have feature, I guess we
can accept some errors. checkUsage is wrong sometimes, but it is still a
good tool.
One of the problem I might run into is performance, if we want this
to treat all Rd files, we are going to want something very efficient,
and it might not be enough to build on top of codetools (which uses
recursion at the R level) , but could make sense to provide a C level
implementation.
Remember what Knuth said about premature optimization. Write it first
in R, and only optimize it if it's not fast enough.
Deal
(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.)
That is good news
This could lead to interesting things as:
- syntax highlighting in sweave (or decumar)
- pretty printing in the console (using ansi characters)
- syntax highlighting in R help files, potentially with hyperlinks
I have requested creation of a project on r-forge. Anyone else want
to play with this ?
I'll sign up once it's going.
Duncan Murdoch
--
Romain Francois
Independent R Consultant
+33(0) 6 28 91 30 30
http://romainfrancois.blog.free.fr
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Re: [R] R-code in html help pages: syntax highlighting
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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Re: [R] R-code in html help pages: syntax highlighting
Wacek Kusnierczyk wrote:
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?
It would certainly be useful to make a difference between the first one
(call to the mean function from base) and the last one.
If we have sufficient evidence of where the function lives, it would be
useful for the syntax highlighter to present this evidence.
I'd like to see function highlighted differently for:
- function in standard R packages
- function exported from the NAMESPACE of the package being highlighted
- function not exported from the NAMESPACE
- function which belongs to a package on which this one depends
It makes the job trivial if we just don't care and put all function
calls to the same basket.
But because of scoping rules, and tricks, there are going to be errors.
f - function( ){
assign( mean, median )
mean( 1:10)
}
f - function( ){
assign( paste(m, e, a, n, sep = ), median )
mean( 1:10)
}
f - function( ){
eval( parse( text = 'assign( paste(m, e, a, n, sep = ),
median )') )
mean( 1:10)
}
... and so on.
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
--
Romain Francois
Independent R Consultant
+33(0) 6 28 91 30 30
http://romainfrancois.blog.free.fr
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Re: [R] R-code in html help pages: syntax highlighting
Romain Francois wrote: Wacek Kusnierczyk wrote: Duncan Murdoch wrote: 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? It would certainly be useful to make a difference between the first one (call to the mean function from base) and the last one. of course! i was referring to duncan's prompt use of the term 'error' in this context. vQ __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
[R] R-code in html help pages: syntax highlighting
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hi, A follow up to my previous post. It'd be good to have syntax highlighting in the html help pages. There is highlight (http://www.andre-simon.de/) which seems to be open source. Since code is delimited in the help file format, it should not be too difficult to run a highlighting program (actually, vim and emacs do this too) recursively and pretty-print all the R examples in the entire CRAN. Including the highlighter with R, or whatever supplementary tools people use to make R html help files could simplify things. I've never written docs or released a package, so I may be understimating the effort it'd take to get this working. Using the r-help gmane archives also leads to plain code. This is probably more trouble than it's worth, since there's no metadata delimiting a block of code and it might be difficult... but grepping through all R-help posts and coloring code would be really nice too. Again, this lands straight into 'nice to have, but not essential' territory. If anyone wants to do this, feel free to. Best, - -J - -- Jose Quesada, PhD. Max Planck Institute, Center for Adaptive Behavior and cognition, Berlin http://www.josequesada.name/ -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.7 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iQIVAwUBSb6RRGMobUVGH+HKAQI2RxAAijNIj7qlBogc9M6lhQ2Ah1Px29iU/uzS 45t5blwNSGVSbAbZF7N7rRcBdn8/c4W8n+oI62nnap0snwLMFW/ynikVNJuBY+XA +yNaO5nIJo5SWu60WkcMinm/ysPZ4o4Jdxr1+lGfJ/ceVSTWPWVLb//GN8QElgwT Vf0ZQUSqfWczzeVDSDtfMKGTJOz4y60eF5hounA/PkzyUd8RRo1WpEXzJHYsCTI+ RwBrYZ5Q30cpKLAJQNeiiv8GDtv7QvJl38uRAqBRK5Ec9CGC0brGZquX8UgHi1q1 1+NzHSt95E4Y0CKWPS48t+eO58MUE8v69gjLa9DdnhII4tCdAUURuP+AsaFm+hzP a7OufMNnh/S8igDmqon0c9W6sJrkDo9DdrZPlu6MFjGQ5SbS6mSfvwSRKVd3RTCN 2/+uz0EwBygq1OKS+Z7Z+kx29UR8+bNXOGaPRlsr5CKcwVV9w3FBvEICuDaP75vj l0d75+2R+CB/R/e2+dMMRCQY5MNWtYuuqoz3jNws59J+0z5K35usLoaKdB7Ez3D6 G2CCBKJSrugT0s8OkhX5pcTiU6NUIrq6q8h7JNEeuR0bniFClXlDrAs9iIdNb4PS oFpqtNJWPLaicHRMnJdnxPCriHa0lmI3QVoGrf6UFtBAXuiOkFxcHUmTcQczyfOm IGyGcgCko3o= =djsT -END PGP SIGNATURE- __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] R-code in html help pages: syntax highlighting
Hi Jose,
highlight is fairly easy to use from command line. I have something like
this when I use R from a console that supports color characters:
highlight - function( fun ){
fun - match.fun( fun )
tf - tempfile()
dump( fun, tf )
system( sprintf( highlight -A -S R %s, tf ) )
unlink( tf )
}
R highlight( glm )
Replace -A with -f -H and you have html output ready for pasting
into a blog or whatever.
See also ?file for how you might want to send the generated output to
the clipboard, so that you only have Control + V to type on the web
browser.
Romain
Jose Quesada wrote:
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Hi,
A follow up to my previous post. It'd be good to have syntax
highlighting in the html help pages. There is highlight
(http://www.andre-simon.de/) which seems to be open source. Since code
is delimited in the help file format, it should not be too difficult
to run a highlighting program (actually, vim and emacs do this too)
recursively and pretty-print all the R examples in the entire CRAN.
Including the highlighter with R, or whatever supplementary tools
people use to make R html help files could simplify things. I've never
written docs or released a package, so I may be understimating the
effort it'd take to get this working.
Using the r-help gmane archives also leads to plain code.
This is probably more trouble than it's worth, since there's no
metadata delimiting a block of code and it might be difficult... but
grepping through all R-help posts and coloring code would be really
nice too. Again, this lands straight into 'nice to have, but not
essential' territory.
If anyone wants to do this, feel free to.
Best,
- -J
- --
Jose Quesada, PhD.
Max Planck Institute,
Center for Adaptive Behavior and cognition,
Berlin
http://www.josequesada.name/
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and provide commented, minimal, self-contained, reproducible code.
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Re: [R] R-code in html help pages: syntax highlighting
On 3/16/2009 1:49 PM, Jose Quesada wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hi, A follow up to my previous post. It'd be good to have syntax highlighting in the html help pages. This needs two things: making the highlight program available to R, and then adding it to the Rd to HTML conversion code. In current releases that conversion is done in Perl code, but with R 2.9 an R-based converter will be available (but not used by default; too many CRAN packages have too many errors in their Rd files, and the new converter is more sensitive to such things). So sometime after 2.9.0 is released, it would seem like a reasonable project to modify the conversion to allow for syntax highlighting. One likely complaint is that the highlighting will be inaccurate. Typically highlighters just have a list of things they know to be important names, they don't actually take scoping rules into account (so mean gets highlighted as a built in function even when used as mean - (x + y)/2 for example). So it would be interesting if someone wanted to do the work to make a syntax highlighter that was accurate. I'd say the R core work on something like this would be to provide the hook for a user to link in their own favourite highlighter; I doubt if we'd want to take on the bitching that the inaccurate highlighting would attract. Duncan Murdoch There is highlight (http://www.andre-simon.de/) which seems to be open source. Since code is delimited in the help file format, it should not be too difficult to run a highlighting program (actually, vim and emacs do this too) recursively and pretty-print all the R examples in the entire CRAN. Including the highlighter with R, or whatever supplementary tools people use to make R html help files could simplify things. I've never written docs or released a package, so I may be understimating the effort it'd take to get this working. Using the r-help gmane archives also leads to plain code. This is probably more trouble than it's worth, since there's no metadata delimiting a block of code and it might be difficult... but grepping through all R-help posts and coloring code would be really nice too. Again, this lands straight into 'nice to have, but not essential' territory. If anyone wants to do this, feel free to. Best, - -J - -- Jose Quesada, PhD. Max Planck Institute, Center for Adaptive Behavior and cognition, Berlin http://www.josequesada.name/ -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.7 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iQIVAwUBSb6RRGMobUVGH+HKAQI2RxAAijNIj7qlBogc9M6lhQ2Ah1Px29iU/uzS 45t5blwNSGVSbAbZF7N7rRcBdn8/c4W8n+oI62nnap0snwLMFW/ynikVNJuBY+XA +yNaO5nIJo5SWu60WkcMinm/ysPZ4o4Jdxr1+lGfJ/ceVSTWPWVLb//GN8QElgwT Vf0ZQUSqfWczzeVDSDtfMKGTJOz4y60eF5hounA/PkzyUd8RRo1WpEXzJHYsCTI+ RwBrYZ5Q30cpKLAJQNeiiv8GDtv7QvJl38uRAqBRK5Ec9CGC0brGZquX8UgHi1q1 1+NzHSt95E4Y0CKWPS48t+eO58MUE8v69gjLa9DdnhII4tCdAUURuP+AsaFm+hzP a7OufMNnh/S8igDmqon0c9W6sJrkDo9DdrZPlu6MFjGQ5SbS6mSfvwSRKVd3RTCN 2/+uz0EwBygq1OKS+Z7Z+kx29UR8+bNXOGaPRlsr5CKcwVV9w3FBvEICuDaP75vj l0d75+2R+CB/R/e2+dMMRCQY5MNWtYuuqoz3jNws59J+0z5K35usLoaKdB7Ez3D6 G2CCBKJSrugT0s8OkhX5pcTiU6NUIrq6q8h7JNEeuR0bniFClXlDrAs9iIdNb4PS oFpqtNJWPLaicHRMnJdnxPCriHa0lmI3QVoGrf6UFtBAXuiOkFxcHUmTcQczyfOm IGyGcgCko3o= =djsT -END PGP SIGNATURE- __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] R-code in html help pages: syntax highlighting
Duncan Murdoch wrote: On 3/16/2009 1:49 PM, Jose Quesada wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hi, A follow up to my previous post. It'd be good to have syntax highlighting in the html help pages. This needs two things: making the highlight program available to R, and then adding it to the Rd to HTML conversion code. In current releases that conversion is done in Perl code, but with R 2.9 an R-based converter will be available (but not used by default; too many CRAN packages have too many errors in their Rd files, and the new converter is more sensitive to such things). So sometime after 2.9.0 is released, it would seem like a reasonable project to modify the conversion to allow for syntax highlighting. One likely complaint is that the highlighting will be inaccurate. Typically highlighters just have a list of things they know to be important names, they don't actually take scoping rules into account (so mean gets highlighted as a built in function even when used as mean - (x + y)/2 for example). So it would be interesting if someone wanted to do the work to make a syntax highlighter that was accurate. I'd say the R core work on something like this would be to provide the hook for a user to link in their own favourite highlighter; I doubt if we'd want to take on the bitching that the inaccurate highlighting would attract. Hi Duncan, It would be pretty easy to use the output from the R parser (which is never wrong, is it?), and dump some markup out of it. For example the showTree function in codetools dumps an R expression as Lisp, this is not too far from generating html, or any other markup. As this sounds like fun, I'll volunteer to do something about this. Another advantage is that we can imagine to plug hyperlinks in R code that lives in html help pages. Romain Duncan Murdoch There is highlight (http://www.andre-simon.de/) which seems to be open source. Since code is delimited in the help file format, it should not be too difficult to run a highlighting program (actually, vim and emacs do this too) recursively and pretty-print all the R examples in the entire CRAN. Including the highlighter with R, or whatever supplementary tools people use to make R html help files could simplify things. I've never written docs or released a package, so I may be understimating the effort it'd take to get this working. Using the r-help gmane archives also leads to plain code. This is probably more trouble than it's worth, since there's no metadata delimiting a block of code and it might be difficult... but grepping through all R-help posts and coloring code would be really nice too. Again, this lands straight into 'nice to have, but not essential' territory. If anyone wants to do this, feel free to. Best, - -J - -- Jose Quesada, PhD. Max Planck Institute, Center for Adaptive Behavior and cognition, Berlin http://www.josequesada.name/ -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.7 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iQIVAwUBSb6RRGMobUVGH+HKAQI2RxAAijNIj7qlBogc9M6lhQ2Ah1Px29iU/uzS 45t5blwNSGVSbAbZF7N7rRcBdn8/c4W8n+oI62nnap0snwLMFW/ynikVNJuBY+XA +yNaO5nIJo5SWu60WkcMinm/ysPZ4o4Jdxr1+lGfJ/ceVSTWPWVLb//GN8QElgwT Vf0ZQUSqfWczzeVDSDtfMKGTJOz4y60eF5hounA/PkzyUd8RRo1WpEXzJHYsCTI+ RwBrYZ5Q30cpKLAJQNeiiv8GDtv7QvJl38uRAqBRK5Ec9CGC0brGZquX8UgHi1q1 1+NzHSt95E4Y0CKWPS48t+eO58MUE8v69gjLa9DdnhII4tCdAUURuP+AsaFm+hzP a7OufMNnh/S8igDmqon0c9W6sJrkDo9DdrZPlu6MFjGQ5SbS6mSfvwSRKVd3RTCN 2/+uz0EwBygq1OKS+Z7Z+kx29UR8+bNXOGaPRlsr5CKcwVV9w3FBvEICuDaP75vj l0d75+2R+CB/R/e2+dMMRCQY5MNWtYuuqoz3jNws59J+0z5K35usLoaKdB7Ez3D6 G2CCBKJSrugT0s8OkhX5pcTiU6NUIrq6q8h7JNEeuR0bniFClXlDrAs9iIdNb4PS oFpqtNJWPLaicHRMnJdnxPCriHa0lmI3QVoGrf6UFtBAXuiOkFxcHUmTcQczyfOm IGyGcgCko3o= =djsT -END PGP SIGNATURE- __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. -- Romain Francois Independent R Consultant +33(0) 6 28 91 30 30 http://romainfrancois.blog.free.fr __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] R-code in html help pages: syntax highlighting
On 3/16/2009 2:50 PM, Romain Francois wrote: Duncan Murdoch wrote: On 3/16/2009 1:49 PM, Jose Quesada wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hi, A follow up to my previous post. It'd be good to have syntax highlighting in the html help pages. This needs two things: making the highlight program available to R, and then adding it to the Rd to HTML conversion code. In current releases that conversion is done in Perl code, but with R 2.9 an R-based converter will be available (but not used by default; too many CRAN packages have too many errors in their Rd files, and the new converter is more sensitive to such things). So sometime after 2.9.0 is released, it would seem like a reasonable project to modify the conversion to allow for syntax highlighting. One likely complaint is that the highlighting will be inaccurate. Typically highlighters just have a list of things they know to be important names, they don't actually take scoping rules into account (so mean gets highlighted as a built in function even when used as mean - (x + y)/2 for example). So it would be interesting if someone wanted to do the work to make a syntax highlighter that was accurate. I'd say the R core work on something like this would be to provide the hook for a user to link in their own favourite highlighter; I doubt if we'd want to take on the bitching that the inaccurate highlighting would attract. Hi Duncan, It would be pretty easy to use the output from the R parser (which is never wrong, is it?), and dump some markup out of it. For example the showTree function in codetools dumps an R expression as Lisp, this is not too far from generating html, or any other markup. As this sounds like fun, I'll volunteer to do something about this. Another advantage is that we can imagine to plug hyperlinks in R code that lives in html help pages. That sounds great. I'd be happy to work with you to add hooks to the conversion functions so your highlighters can be called (but not for a few weeks: we're at a very busy time of year here). But if you want to get started, and figure out what you need, getting in touch with me in early April would be fine. Duncan Murdoch __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] R-code in html help pages: syntax highlighting
It would be pretty easy to use the output from the R parser (which is never wrong, is it?), and dump some markup out of it. For example the showTree function in codetools dumps an R expression as Lisp, this is not too far from generating html, or any other markup. As this sounds like fun, I'll volunteer to do something about this. Another advantage is that we can imagine to plug hyperlinks in R code that lives in html help pages. This also sounds like a good idea for a google summer of code project - that way you might be able to get a student to give you a hand as well. Hadley -- http://had.co.nz/ __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] R-code in html help pages: syntax highlighting
hadley wickham wrote: It would be pretty easy to use the output from the R parser (which is never wrong, is it?), and dump some markup out of it. For example the showTree function in codetools dumps an R expression as Lisp, this is not too far from generating html, or any other markup. As this sounds like fun, I'll volunteer to do something about this. Another advantage is that we can imagine to plug hyperlinks in R code that lives in html help pages. This also sounds like a good idea for a google summer of code project - that way you might be able to get a student to give you a hand as well. Hadley That did cross my mind earlier this evening, it just seems a bit too easy to last all summer, but maybe I am missing something difficult. I will start to play with this over the next few days, and make up my mind. One of the problem I might run into is performance, if we want this to treat all Rd files, we are going to want something very efficient, and it might not be enough to build on top of codetools (which uses recursion at the R level) , but could make sense to provide a C level implementation. This could lead to interesting things as: - syntax highlighting in sweave (or decumar) - pretty printing in the console (using ansi characters) - syntax highlighting in R help files, potentially with hyperlinks I have requested creation of a project on r-forge. Anyone else want to play with this ? Romain -- Romain Francois Independent R Consultant +33(0) 6 28 91 30 30 http://romainfrancois.blog.free.fr __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] R-code in html help pages: syntax highlighting
On 16/03/2009 5:06 PM, Romain Francois wrote: hadley wickham wrote: It would be pretty easy to use the output from the R parser (which is never wrong, is it?), and dump some markup out of it. For example the showTree function in codetools dumps an R expression as Lisp, this is not too far from generating html, or any other markup. As this sounds like fun, I'll volunteer to do something about this. Another advantage is that we can imagine to plug hyperlinks in R code that lives in html help pages. This also sounds like a good idea for a google summer of code project - that way you might be able to get a student to give you a hand as well. Hadley That did cross my mind earlier this evening, it just seems a bit too easy to last all summer, but maybe I am missing something difficult. I will start to play with this over the next few days, and make up my mind. It depends on your standards. You said you want R to parse the code in the Rd file. That's going to be hard, because Rd files contain something that is only R-like, as far as the parser is concerned. You'll need to convert it into R code before you can pass it to the R parser. And then there's the question of scoping, which gets into the evaluator, not just the parser. (The parser only recognizes mean as an identifier; it's the evaluator that decides whether it's the function in the base package or a local variable.) 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. One of the problem I might run into is performance, if we want this to treat all Rd files, we are going to want something very efficient, and it might not be enough to build on top of codetools (which uses recursion at the R level) , but could make sense to provide a C level implementation. Remember what Knuth said about premature optimization. Write it first in R, and only optimize it if it's not fast enough. (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.) This could lead to interesting things as: - syntax highlighting in sweave (or decumar) - pretty printing in the console (using ansi characters) - syntax highlighting in R help files, potentially with hyperlinks I have requested creation of a project on r-forge. Anyone else want to play with this ? I'll sign up once it's going. Duncan Murdoch __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
