Can knit2pdf use the global environment?
knitr, r
Solution
The problems with the examples in the question seem to have nothing to do with environments. Everything will compile correctly and without warnings if the `output` argument is left off of `knit2pdf`.
For reference, I was using knitr 1.1 on R 2.15.3 on Windows 7. I'll let Yihui know as it appears to be a bug in `knit2pdf` (which calls `tools::texi2pdf`, which doesn't accept an output file path).
UPDATE: The problem has been fixed in the development version of `knitr`, available here.
It's also worth noting that the `Compile PDF` button in RStudio does not use your current environment, so if you want to have access to global variables and you are using RStudio, make an explicit call to the appropriate `knit` function rather than relying on the shortcut. In fact, it doesn't use `knit2pdf` directly, rather it calls `rmarkdown::render`.
Problem
In this answer, @Yihui said that `knitr` uses the global environment. This confused me--my experience had been that it doesn't. I never really use `knit` though, I usually go straight to PDF. In a little experiment, it seems that `knit` does use the global environment (or whatever environment you specify using the `envir` argument), but that `knit2pdf` doesn't. Minimal example: global_test.Rnw file ``` \documentclass{article} \begin{document} <<>>= print(x) @ \end{document} ``` R Script: ``` x <- "Hello World" knit(input="global_test.Rnw") # Works as expected, could now call tools::texi2pdf to generate pdf. knit2pdf(input="global_test.Rnw") # Doesn't ``` The latter generates PDF file that won't display and gives a warning: ``` running command '"C:\PROGRA~2\MIKTEX~1.9\miktex\bin\texi2dvi.exe" --quiet --pdf "global.pdf" -I "C:/PROGRA~1/R/R-215~1.3/share/texmf/tex/latex" -I "C:/PROGRA~1/R/R-215~1.3/share/texmf/bibtex/bst"' had status 1 ``` I tried passing an environment to `knit2pdf` (`envir = globalenv()`) hoping it would be `...` passed on, I just get an unused argument error. Generally, I know that referencing the global environment is poor form, but is there a way to do it with `knit2pdf`, or to pass an environment explicitly, or am I better off using `brew` and `sprintf` as in @Ramnath's answer to the same question above? In my use case, I don't think `tools::texi2pdf` is useful because I need to compile with XeLaTeX, which `knit2pdf` handles effortlessly.