RE: [Axiom-developer] Check for item in PATH in Emacs?

[Page, Bill]

On Tuesday, May 02, 2006 11:13 PM C Y wrote:
> 
> Does anybody know of a way to check for, say, "axiom" in the
> PATH on a particular system from Emacs?  Trying to run something
> via comint seems to result in an error which stops everything.
> I'm trying to first run "axiom" if it's available (it turns out
> graphics do work when run from the Emacs buffer) and if it isn't
> available fall back to "AXIOMsys".  I know I could do some hackery
> with running "which axiom" on Linux but I'm hoping for something
> more straightforward and portable.
> 
I'm no emacs hacker, but it looks like some code in emacs esh-ext
might do what you want. See:

http://www.cgl.uwaterloo.ca/~mmwasile/data/elisp/eshell-2.4.2/esh-ext.el

...
(defun eshell-search-path (name)
  "Search the environment path for NAME."
  (if (file-name-absolute-p name)
      name
    (let ((list (parse-colon-path (getenv "PATH")))
          suffixes n1 n2 file)
      (while list
        (setq n1 (concat (car list) name))
        (setq suffixes eshell-binary-suffixes)
        (while suffixes
          (setq n2 (concat n1 (car suffixes)))
          (if (and (or (file-executable-p n2)
                       (and eshell-force-execution
                            (file-readable-p n2)))
                   (not (file-directory-p n2)))
              (setq file n2 suffixes nil list nil))
          (setq suffixes (cdr suffixes)))
        (setq list (cdr list)))
      file)))
...

Regards,
Bill Page.