Feature request: child.path

[pank]

When doing larger R project I might have a project structure like this:

figures  [dir]
sections [dir]
main.Rnw
data.dta 

I can put pictures in figures with fig.path and cache is sorted into cache.dir. It would be natural to also have a child.dir where knitr automatically looks for children.

[yihui]

Currently paths of child documents are assumed to be relative to the path of parent documents, so we probably do not need an extra argument to set the path. For example,

<<set-child, child=a.Rnw;b/c.Rnw>>=
@ 

This will include two child documents a.Rnw and b/c.Rnw into the parent document, and both are under the path of the parent.

[pank]

The point would be that you would not have to type b. In other words, b would be a search path and I would not have to write it every time. In theory, I would also be able to do

mv b c # In my terminal

and only correct it one place in my main Rnw file.

[yihui]

Then you will have to write child=../a.Rnw;c.Rnw in my above case if you set the search path to be ./b/, which may not save you a lot of typing efforts. Anyway, I see your point now. The implementation should be trivial, and I will consider it. Thanks!

[yihui]

You can set opts_knit$set(child.path = 'b') now.

[stla]

I don't manage to use this option.

<<setup>>=
r <- system.file("rsb", "catalog", "sweave_files", package="RSBpackage00")
knitr::opts_knit$set(
  root.dir = r,
  child.path = r
)
@

Then this does not work:

<<child="child.Rnw">>=
@

But this obviously works:

<<child=paste0(r, "/child.Rnw")>>=
@

[stla]

I see two problems:

In readLines(if (is.character(input2)) { :
  cannot open file './C:/PortableApps/R-portable_3.3.1/App/R-Portable/library/RSBpackage00/rsb/catalog/sweave_fileschild.Rnw': Invalid argument

The first one is easy to fix: child="/child.Rnw" (the slash)

The second one is the dot here: ./C:/....

[stla]

A solution thanks to http://stackoverflow.com/a/36728257/1100107:

<<setup>>=
make.path.relative = function(base, target) {
  common <- sub('^([^|]*)[^|]*(?:\\|\\1[^|]*)$', '^\\1/?', paste0(base, '|', target))
  paste0(gsub('[^/]+/?', '../', sub(common, '', base)),
         sub(common, '', target))
}
r <- system.file("rsb", "catalog", "sweave_files", package="RSBpackage00")
c <- make.path.relative(getwd(), r)
knitr::opts_knit$set(
  root.dir = r,
  child.path = c
)
@

<<child="/child.Rnw">>=
@

[stla]

@yihui ,
This relative path causes a problem: it's not possible on Windows (I think) to do a relative path from a hard drive to another one.

[github-actions]

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