elisp
Tab Completion for Custom Commands
A lot of commands in Emacs take input from the minibuffer, the little one-line area at the bottom of the editor. When you are writing your own commands you will often make use of the same facility. In this article I want to show you one way of doing that which will provide tab completion for your custom functions. I’m going to use a simple example out of my own dot Emacs file. This is the function that was in my last email, my function for opening org-mode log files. I keep one org-mode file for each project, in a log directory, split up by year. So I wanted a simple command I could bind to a key that would let me type in a project name and open the file. So I have this: (defun open-project-log-file (project) "Opens a ...
Indent on Save, Maybe
While working on a .NET project, I have noticed that when I do many things, Visual Studio takes that time to re-indent large amounts of my code. But most of the time I’m writing it out in Emacs, so this makes my diffs a pain in the ass. But it got me to thinking about indenting on save. And then—lo—the very subject came up today on the Emacs mailing list. A teacher was asking for a way to make C++ mode automatically re-indent the whole file on save, to make his students use. I don’t know if he was sick of seeing horrible indentation or what. There is a hook in Emacs called the before-save-hook, to which you can add functions to be called just before saving the contents of a buffer. A great example: (add-hook 'before-save-hook 'delete-trailing-whitespace) Will call delete-trailing-whitespace whenever you save any file. So ...
SQL Movement Commands
Most programming modes in Emacs support two commands, beginning-of-defun and end-of-defun. These move you to the beginning and end of the nearest function, and by default are bound to C-M-a and C-M-e, respectively. However, sql-mode does not have anything similar. I have the above two commands bound to C-up and C-down for quickly moving around functions, but I find myself often hitting them when viewing an SQL file to move through tables---which doesn't work. Fortunately that functionality is pretty easy to add. For my fellow Emacs users, here is some code I whipped up that you can use to easily move between tables and views. (defconst sql-beginning-of-table-or-view-regexp "^\\s-*create\\s-+\\(?:table\\|view\\)" "Regular expression for matching the start of an SQL table or view definition.") (defun sql-prev-table-or-view () "Move backwards to the beginning of the nearest table or view from point." (interactive) (re-search-backward sql-beginning-of-table-or-view-regexp nil 'noerror)) (defun sql-next-table-or-view () "Move forwards to the beginning of the nearest table or view from point." (interactive) (re-search-forward sql-beginning-of-table-or-view-regexp nil 'noerror)) Then you ...