Automatic Casing - Ada Mode

12 Automatic Casing

Casing of identifiers, attributes and keywords is automatically performed while typing when the variable ada-auto-case is set. Every time you press a word separator, the previous word is automatically cased.

You can customize the automatic casing differently for keywords, attributes and identifiers. The relevant variables are the following: ada-case-keyword, ada-case-attribute and ada-case-identifier.

All these variables can have one of the following values:

downcase-word: The previous word will simply be in all lower cases. For instance My_vARIable is converted to my_variable.
upcase-word: The previous word will be fully converted to upper cases. For instance My_vARIable is converted to MY_VARIABLE.
ada-capitalize-word: All letters, except the first one of the word and every letter after the '_' character are lower cased. Other letters are upper cased. For instance My_vARIable is converted to My_Variable.
ada-loose-case-word: No letters is modified in the previous word, except the ones after the '_' character that are upper cased. For instance My_vARIable is converted to My_VARIable.
ada-no-auto-case: Do nothing. This can be used to disable some specific aspects of the auto-casing, for instance if you have some special rules for identifiers, not covered by the other functions above, but still want the keywords to be lower-cased.

These functions, although they will work in most cases, will not be accurate sometimes. The Ada mode allows you to define some exceptions, that will always be cased the same way.

The idea is to create a dictionary of exceptions, and store it in a file. This file should contain one identifier per line, with the casing you want to force. The default name for this file is ~/.emacs_case_exceptions. You can of course change this name, through the variable ada-case-exception-file.

Note that each line in this file must start with the key word whose casing you want to specify. The rest of the line can be used for comments (explaining for instance what an abbreviation means, as recommended in the Ada 95 Quality and Style, paragrpah 3.1.4). Thus, a good example for this file could be:

     DOD        Department of Defense
     Text_IO
     GNAT       The GNAT compiler from Ada Core Technologies

When working on project involving multiple programmers, we recommend that every member of the team sets this variable to the same value, which should point to a system-wide file that each of them can write. That way, you will ensure that the casing is consistent throughout your application(s).

There are two ways to add new items to this file: you can simply edit it as you would edit any text file, and add or suppress entries in this file. Remember that you should put one entity per line. The other, easier way, is to position the cursor over the word you want to add, in an Ada buffer. This word should have the casing you want. Then simply select the menu Ada->Edit->Create Case Exception, or the key C-c C-y. The word will automatically be added to the current list of exceptions and to the file.

It is sometimes useful to have multiple exception files around (for instance, one could be the standard Ada acronyms, the second some company specific exceptions, and the last one some project specific exceptions). If you set up the variable ada-case-exception-file as a list of files, each of them will be parsed and used in your emacs session.

However, when you save a new exception through the menu, as described above, the new exception will be added to the first file in the list only. You can not automatically add an exception to one of the other files, although you can of course edit the files by hand at any time.

Automatic casing can be performed on port or whole buffer using:

C-c C-b: Adjust case in the whole buffer.
C-c C-y: Create a new entry in the exception dictionary, with the word under the cursor
C-c C-t: Rereads the exception dictionary from the file ada-case-exception-file.