parse/INSTALL feature request(s)
On 10/21/2006 6:36 PM, Michael Toews wrote:
What would be possible is to do like other preprocessors do, and put comments into the source file to indicate the origin of each line: then the parser could tell you the location in the original file, which would be a lot more useful.
I think what you are referring to is already nicely implemented
Thank you.
(in R/src/main/source.c lines 89 to 97), and the errors are correctly shown in my example as lines 1222 to 1223. However, these line numbers are irrelevant to the original files, as they been concatenated into one large file (I think on line 765 of R/src/scripts/INSTALL.in ).
No, that's not what I was referring to. Preprocessors put lines like #line 3 "header.h" into their output so that the compiler can put useful debugging information into files when it processes them. R could do that when it concatenates the files, and then tell you the origin of each line, not the relatively useless line number from the concatenated file. (A very simple version would add a record like that on every line, and that would work with the current error reporting system; a slightly more sophisticated version would just put those lines in between each concatenated file, and then the error reporting would need to be made aware of them.) This
single file is loaded into an R environment (on line 790 of INSTALL.in), which is also the region where my original error from 'R CMD INSTALL' was thrown. The loading is done by the 'tools:::makeLazyLoading' function, which loads in the single R-source file into a fresh environment for the package. I'm unsure of why a single R source file is needed in INSTALL (which limits the ability to show any offending file names and their line numbers). The functions in R/src/library/tools/R/makeLazyLoad.R could perhaps be made a bit more versatile to individually read the R source files for a package using a 'pattern="\.R$"', and throw an error from 'sys.source' displaying the file name, and other error messages from 'parse'. This is simply a feature-request suggestion, but as Gabor advised, I should really develop my functions file-by-file.
I'm reasonably hopeful that version 2.5.0 will have more source level debugging support in it, at least to the level of the "slightly more sophisticated version", and maybe better than that. If you'd like to help with this, you can see the (currently extremely unstable and incomplete) code on the djm-source branch in the repository. No support for "#line" yet. Duncan Murdoch