Error displaying `mumamo-major-modes' and `mumamo-heredoc-modes' customization widgets

[Daniel Hackney]

When trying to display `mumamo-major-modes', an error is signaled:

  widget-apply: Symbol's function definition is void: nil

The problem is that `ourcomments-widgets' has not yet been loaded to provide the definition for the widget.

For `mumamo-heredoc-modes', widget formatting is not applied if there are symbols in the list which are not yet defined. For a stock Emacs 24.1, `groovy-mode' is not included and so prevents the customize widget from displaying the values properly.

Changing the definition from

  major-mode-function

to

  (choice
    (major-mode-function :tag "Major mode")
    (symbol :tag "Major mode (not yet loaded)"))

as is done in `mumamo-major-modes' fixes this problem.

On a side note: according to `(elisp) Composite Types', a simpler format for `defcustom' type declarations like in `mumamo-heredoc-modes' would be replacing:

  :type '(repeat
            (list
             regexp
             (function :tag "Major mode")))

with

  :type '(alist
           :key-type symbol
            :value-type (group symbol))

The difference is mostly stylistic.

I'm on Emacs 24.1 with a version of nXhtml from a week or two ago.
h