how to expand directory with awk files - vim

Question

I have created a scriptdirectory
let $MYSCRIPTS = $VIM."/vimfiles/my_scripts-docs"
($VIM = C:\Program Files\Vim)
this works fine:
exe "e ".expand('$MYSCRIPTS/vim-calc_vb.txt')
This doesn't work and I can't find out why:
exe "!awk -f ".expand('$MYSCRIPTS/my-awk-script.awk')
exe "!awk -f ".expand('$MYSCRIPTS\my-awk-script.awk')
error:
awk: fatal: can't open source file 'C:/Program'
It works fine when I put the .awk file in the root but not when
I put it in a vim directory or whatever directory under C:\program files
Why does .txt files expand and .awk files not?
How can I let vim know where the awk file is under vimfiles?

Answer 1

Why do you need expand() and not just
fnameescape($MYSCRIPTS.'/vim-calc_vb.txt')
(for the exe "e") and
shellescape($MYSCRIPTS.'/my-awk-script.awk, 1)
(for !awk …)?
Based on your
awk: fatal: can't open source file 'C:/Program'
It works fine when I put the .awk file in the root but not when
I put it in a vim directory or whatever directory under C:\program files
I see that absence of shellescape() is the problem here, not expand(), but it does not make the former useful. It is useful for changing \ to / on windows. Just surround your expand() calls with fnameescape()/shellescape(…, 1):
" None is needed here: `:e` expands `$` on its own
e $MYSCRIPTS/vim-calc_vb.txt
exe "!awk -f ".shellescape(expand('$MYSCRIPTS\my-awk-script.awk'), 1)