Friday, January 9, 2009

emacs python mode from scratch: stage 18 - miscellany

stage 19 - miscellany

A grab bag of functions to finish us up:


  • python-jython-packages
  • python-maybe-jython

    I don't really care too much about jython support so this won't get much more that a brief inspection. python-jython-packages seems to be a list of module names that if found in a package will cause jython mode to be used

    python-maybe-jython is the function that uses the above list among other things to magically determine whether or not to use python or jython mode.

  • python-fill-paragraph

    Provides a python aware fill-paragraph-function. The usual process would be to define paragraph-start and paragraph-separate and let fill do it's magic, but apparently this doesn't work quite right for the last paragraph in a multiline string. So instead This function narrows the string itself and does the fill action on that.

  • python-shift-left
  • python-shift-right

    Move some code left or right by the requested number of columns (defaulting to the prima facie indentation level). If there is no region selected then just work with current line. This works by iterating over every line and running indent-rigidly. There is less code for the python-shift-right variation since you don't have to look out for the case where you run out of room for shifting.

  • python-outline-level

    get outline-level. This is just the multiple of python-indent of the current indentation level.

  • python-current-defun

    Work up an indentation level at a time (ie def or class) and keep track of the names of the def and class entities along the way.

    This is used by add-log (add-log.el). apparently this is some sore of functionality for working with change logs. this function gives a way to refer to the name of the function where point currently resides. But honestly I'm not really sure how this fits into the big picture. This may well be some feature i depend on, but I'm having trouble figuring out what features use this and why.

    If you run M-x add-change-log-entry it opens up something called a change log. I guess I'll just keep my eyes open for this in the future.

  • python-mark-block

    Mark the block. Just as you'd expect.

So that's pretty much the end except for some little details here and there. This was an interesting exercise though if I had thought about how long this was going to take I'm not sure I would have started down this path. I definitely learned a lot, but the main thing I learned was how little I really know about emacs. Now that I'm finished I find a nice little tutorial on how language modes work. Well at least I know what they are talking about now. My main lesson I guess is that I really need to learn emacslisp if I want to become a master. But even then I will still have a lot to learn about the actual environment. But I'm getting there.

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