fill-paragraph with pre and postfix

[Jacob Gerlach <jacobgerlach@gmail.com>]

Hi list,

A project I'm working on uses a handling function for some command line
documentation:

  blk("  I want to format my documentation like this.                  ");

In order to match the convention for our project, it should include the two
leading spaces and be filled with spaces out to column 70.

The only built in functionality I could find to help with this is
"fill-prefix". Besides not handling the end of the line, I had some trouble
where fill-paragrah didn't seem to actually fill at fill-column like I
expected when I defined a custom prefix.

So my first question is - have I missed a built in capability to do this?
(Alternatively, is there a library in the repos?)

Assuming the answer is no, I set out to write a function that would take a
paragraph of text, fill the text, and wrap it in the function, but I ran in
to some difficulties:

(defun my-fill-and-wrap (start end)
  "Fills region and wrap in blk(  \"...\");"
  (interactive "r")
  (let ((fill-column 70)
        (fill-prefix "  blk(  \""))
    (goto-char start)
    (fill-paragraph)
    (save-excursion
      (while (< (point) end)
        (end-of-line)
        (insert-char " "
          (- 70 (- (line-end-position) (line-beginning-position))))
        (insert "\");")
        (forward-line))))))

Executing this function seems to do nothing. No filling, or any change to
the text for that matter. Any pointers on what I'm doing wrong would be
greatly appreciated.

Jake