Irreal

Artur Hefczyc has an nice table of the Emacs keybindings. They are listed alphabetically by command name, not by action, so you need to know a good approximation to the name of the command you’re trying to run. It’s a nice table and worth bookmarking or even printing out if you’re inclined to use paper cheat sheets.

Of course, you can always get a complete list of the current keybindings for your Emacs with 【Ctrl+h b】 but I find it difficult to locate the command I’m looking for with it.

Just a quickie. I was browsing around in Aaron Hawley’s Giant Emacs Reference Sheet when I came across this little ditty:

C-x d *.c RET Q int RET long    

It was described as “replace ‘long’ for ‘int’ in .c files.” I thought, “Boy, that’s really handy” and then I realized that it’s just

1. Enter dired and list all the .c files
2. Do a query replace substituting long for int

something that I’ve probably blogged about in the past.

Still, it does seem to gain power when you think of it as one command. And, if for only a moment, I thought I’d found something new and wonderful.

I mostly use isearch-forward, 【Ctrl+s】, and isearch-backward, 【Ctrl+r】, to search for words or phrases in a buffer. Sometimes, though, it’s convenient to see all the matches at once. Emacs has a set of commands that make this easy.

The easiest to use is highlight-phrase, which is bound to the 【Meta+s h p】 sequence. It will ask you for a phrase and highlighting color and then highlight all the matching phrases in the buffer. The nice thing about highlight-phrase is that any whitespace is automatically converted to arbitrary whitespace and initial lower-case letters are made case insensitive so it’s pretty much a “do what I mean” command.

The next command, highlight-regexp, is a little more general. It’s bound to 【Meta+s h r】 and lets you highlight anything that matches an arbitrary regexp.

The command highlight-lines-matching-regexp is similar to highlight-regexp except that it highlights the entire line that contains the match to the regular expression. It is bound to 【Meta+s h l】.

Finally, you can un-highlight the matches with unhighlight-regexp, bound to 【Meta+s h u】.

Summary

Update: let → set.

As I mentioned in my Emacs 24 Features post, Bozhidar Batsov over at (think) has been using Emacs 24 with great success. He has a new post up that describes how to get Emacs 24 installed on OS X, Linux, and Windows.

For OS X, he recommends just getting the pretest from Emacs for OSX, but I like to compile it from sources. I tried that but had a problem with the libcurses-dev not being found. I haven’t had that problem before but this is the first time I’ve compiled Emacs since I installed Lion so I probably just need to download the sources and compile the library. Leave a comment if you’ve run into this problem and tell us what you did to resolve it.

In any event, after you’ve installed Emacs 24 you may want to look at Batsov’s Emacs Prelude. It’s “an advanced Emacs setup specifically for Emacs 24.” It works with OS X, Linux, and Windows.

Batsov notes that although Emacs 24 is not scheduled for release until Spring 2012, he has been using it for several months and found it to be rock solid. He concludes by saying that there really is no excuse not to switch to Emacs 24 now so if you’re inclined, see Batsov’s post that I linked above to get the details on how to get it installed.

I really like JSON. It’s the perfect mechanism for serializing data; much better, in my opinion, than the typical XML solution. That said, I don’t use it enough to justify installing one of the really nice packages that deal with it such as Steve Yegge’s js2-mode or Edward O’Connor’s json.el. Still, I thought it would be nice to have an Emacs utility that could transform JSON into a standard, readable format.

The other day I came across a post in Richard Ketteierij’s richardlog blog about pretty-printing JSON and XML on Mac OSX. His post had nothing to do with Emacs; it was merely a way of writing reformatted JSON to a file. It occurred to me that this was just what I needed for the occasional lightweight reformatting of JSON. It should work for any system with Python 2.6 or greater installed.

It turns out that the Python distribution comes with a json.tool module that does the work of reformating JSON. For example, here

{"father":{"name":"John Smith", "age":45, "employer":"YoYodyne, inc."},
"mother":{"name":"Wilma Smith", "age":42},
"children":[{"name":"William Smith", "age":15},
         {"name":"Sally Smith","age":17}]}

is some JSON that I used when I first wrote about JSON back in 2009 on my old blog. It’s easy to run this through json.tool by selecting the code and typing 【Ctrl+u Meta+|】 python -m json.tool. Doing that yields

{
    "children": [
        {
            "age": 15, 
            "name": "William Smith"
        }, 
        {
            "age": 17, 
            "name": "Sally Smith"
        }
    ], 
    "father": {
        "age": 45, 
        "employer": "YoYodyne, inc.", 
        "name": "John Smith"
    }, 
    "mother": {
        "age": 42, 
        "name": "Wilma Smith"
    }
}

which is more readable and standardized in the sense that the items are in alphabetical order. As I said, it’s a simple and lightweight solution but quite handy if you deal with JSON only occasionally. If you use JSON a lot you probably have one of the packages mentioned above installed already (or should have).

Update: an example of to get rid of redundant “example.”