AUCTeX: how to compile a file, which does end in '.ins'

Question

I am playing around with some LaTeX's DocStrip package.

(For those interested: it is a LaTeX package, to create documented code, in order to write e.g. a style file and incorporate the documentation in one file. DocStrip will Strip the Documentation and generate a clean and fast loadable Stylefile but is also able, to create an exhaustive documentation on that style file.)

To use DocStrip you usually have two kind of files: the .dtx containing both documentation and the code and a second file, which is similar to a Makefile. Usually it has the file extension .ins to be not mixed up with normal LaTeX files.

If you want to extract the style file (or any other package), you have to run LaTeX on your "Makefile", that is

 latex sample.ins

I want to be able, to use the normal C-c C-c key, to start this compilation. But AUCTeX is adding the extra file extension .tex, so that the real call is

 pdflatex -file-line-error  --synctex=1 -interaction=nonstopmode "\input" sample.ins.tex''

Ho do I configure Emacs/AUCTeX to run

 pdflatex -file-line-error  --synctex=1 -interaction=nonstopmode "\input" sample.ins''

instead?

I already tried to define the master file to be "sample.ins", but even than .tex is added.

Answer 1

Known extensions to AUCTeX are controlled by the variable TeX-file-extensions:

TeX-file-extensions is a variable defined in ‘tex.el’.
Its value is ("tex" "sty" "cls" "ltx" "texi" "txi" "texinfo" "dtx")

Documentation:
*File extensions used by manually generated TeX files.

You can use the customize interface to add "ins" to this list or with something like this in your init file:

(with-eval-after-load "tex"
  (add-to-list 'TeX-file-extensions "ins" t))