Yes this is not a bug and I have implemented this using advice: #+BEGIN_SRC emacs-lisp ;; See https://emacs-china.org/t/file/696 ;; And http://lists.gnu.org/archive/html/emacs-orgmode/2016-07/msg00136.html (defun check-file-exists-advice (orig-fun &optional arg info params) ;; Copied from ob-core.el. May not be compatible. (let* ((org-babel-current-src-block-location (or org-babel-current-src-block-location (nth 6 info) (org-babel-where-is-src-block-head) ;; inline src block (and (org-babel-get-inline-src-block-matches) (match-beginning 0)))) (info (if info (copy-tree info) (org-babel-get-src-block-info))) (merged-params (org-babel-merge-params (nth 2 info) params))) (when (cdr (assoc :file merged-params)) (unless (file-exists-p (cdr (assoc :file merged-params))) (error "File does not exist")))) (funcall orig-fun arg info params))
(advice-add 'org-babel-execute-src-block :around #'check-file-exists-advice) #+END_SRC And this is just a feature request: I’d love to implement this feature in another way. > On Jul 9, 2016, at 12:09 AM, Charles C. Berry <ccbe...@ucsd.edu> wrote: > > On Fri, 8 Jul 2016, Jiajie Chen wrote: > [snip] > >> Now there exists 'org-babel-after-execute-hook'. I want to implement >> this functionality: Check whether the path specified in `:file' exists >> in file system and throw an error if that does not exists. If there is >> `org-babel-before-execute-hook', we can do that instead of using >> advice. I love symmetry :) >> > > Not a bug, of course. > > You can check on things like file existence in a number of ways. > > First, you can put emacs-lisp in header args, for example: > > This evaluates when there is a file called "elisp" in the default directory: > > #+header: :eval (or (file-exists-p "elisp") "no") > #+BEGIN_SRC emacs-lisp :eval (file-exists-p "elisp") > "got it!" > #+END_SRC > > > and this does not (when there is no 'eeeelisp'): > > #+header: :eval (or (file-exists-p "eeeelisp") "no") > #+BEGIN_SRC emacs-lisp > "got it!" > #+END_SRC > > I've illustrated here with `:eval', but `:file' will also take such an elisp > snippet. > > > Alternatively, you can define a function for `org-confirm-babel-evaluate' > that will block evaluation. > > Chuck
