How to configure emacs to properly comment code in php-mode?

Question

I have emacs 23.3.1, running on windows.

php-mode 1.5 from http://php-mode.sourceforge.net/, Modified: 2008-11-04

I think this used to work, but now, when I try to comment out a block of code, using comment-region, which is an interactive compiled Lisp function in `newcomment.el', I get poor results.

Example:

before:

after:

You can see that each line in the commented block has the single-line comment start sequence //, and the multi-line comment-end sequence */.

This is not a huge problem, though it is ugly. The problem comes in when I try to uncomment the block. I get an error, "Can't find comment end". In other words, comment-region is not reversible with C-u comment-region.

I'll see if I can figure this out, but is there a setting I am missing in php-mode?

Anyone know?

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MORE

I didn't put anything in my php-mode-hook function to change the comment-start and comment-end variables. When I debug comment-region I can see they get set to the mismatched pair of // and */ somehow. That explains the weird results of comment-region. I don't believe it's my code that does sets those variables like that.

I tried setting them explicitly in my hook to // and (empty string). In that case, the comment-region looks prettier but it still does not uncomment. I also tried the matched pair of /* and */, but that gave the same results. Uncomment does not succeed; the error is can't find comment end. .

MORE2

I think my syntax table is correct. It shows this:

...which seems right to me.

Answer 1

This solved it for me:

(setq comment-use-syntax t)

I put that in my php-mode hook.

Not sure if this was necessary, but I als included statements to modify the syntax table. The entire hook looks like this:

(defun cheeso-php-mode-fn ()
  "Function to run when php-mode is initialized for a buffer."
  (require 'flymake)
  (flymake-mode 1)

  (setq c-default-style "bsd"
      c-basic-offset 2)

  ;; not sure if necessary or not.
  (modify-syntax-entry ?/ ". 124b" php-mode-syntax-table)
  (modify-syntax-entry ?* ". 23" php-mode-syntax-table)
  (modify-syntax-entry ?\n "> b"  php-mode-syntax-table)
  (modify-syntax-entry ?\^m "> b" php-mode-syntax-table)

  (setq comment-multi-line nil ;; maybe
        comment-start "// "
        comment-end ""
        comment-style 'indent
        comment-use-syntax t))

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The help statement for comment-use-syntax says that major modes should set it. In the php buffer I was editing, the variable was set to nil. I'm guessing it was set by php-mode; in any case it was not set by me. Setting this to t and insuring that the syntax table had the appropriate values did the trick.

I should say that I only use C-style comments in php; I don't use the # .