Wednesday, August 31, 2011

Vim tags

Continuing on with my exploration of Vim features I've yet to use, let's explore tags.

Tags are like bookmarks. They let you jump around to different places in your file that you might want to reference, like a class definition for example.

Create a tag like so: ":tag tagname". This tags the current line number with the name you provide. Alternatively, you can use the shortcut CTRL + ]. The tag name will be taken from either the character under your cursor, or if you've highlighted a word or phrase, it will be used.

":tags" shows you your list of tags.

:tags
# TO tag FROM line in file/text
> 1 1 LongTextAnswer 8 q = LongTextAnswer()

Each time I show my :tags I get this error:

E433: No tags file.

This may also explain why my tags queue only contains the most recent tag I create. Further reading reveals that the tags file is created by the program ctags. I'll try installing exuberant-ctags and see what affect that has on my operation.

sudo apt-get install exuberant-ctags

Restarting vim and trying the :tags command again showed that my tags file could still not be found. I found a nice little page that describes the rest of the process that one must go through to get your tags file set up. Follow the link to learn more.


On a related note, you can read ctags in python:






Vim Execute Mode

I use vim and gvim every day. I'm so productive using the small subset of available commands that I know that I tend not to explore the question, "what else can I do with Vim?"

Take Execute Mode for example. In 10 years of Vim use, I've never tried it. Let's fix that now.

You enter Execute Mode by pressing capital Q (shift + q) when in normal mode. You'll see this at the bottom of your window.

Entering Ex mode. Type "visual" to go to Normal mode.
:

This seems familiar enough, but this is different than when you simply type ":" to enter a command at the bottom of the screen in normal mode. In normal mode, typing ":10 " + enter takes you to the tenth line in the document. In Execute Mode, ":10" + enter displays the tenth line just below your cursor. Hitting return again shows the eleventh line, and so on. You are not editing the document in this mode, simply accessing it. Interesting, but not yet terribly useful. Let's see what else you can do.

:w filename

This writes the file, just as it would if you had typed :w filename in normal mode, except again, instead of returning you to editing the document, you remain in Execute mode, meaning that the ":" appears again, awaiting your next command.

I'm afraid I can't imagine too many good reasons to use Execute Mode. The best use-case I can find is that you could use the :n, where n is a line number, feature view a section of the document you are not working on without leaving the section you are working on. If you have any tips on how Execute Mode makes your life easier, please leave a comment.


Monday, August 08, 2011

Safari URL opens new window

Here's a strange quirk I encountered while working with Safari mobile: HTML anchors (<a href="http://www.blogger.com/something.html">click</a>) open a new Safari browser instance---every time.

Now that can't be right. As it turns out, this is indeed the standard behavior when the target attribute is not explicitly set in the anchor. Apple does provide a work around setting:

http://www.naquah.net/blog/dennis/2008/03/21/how-to-enable-single-window-mode-in-safari

There are many instances when web designers don't need targets, and they are omitted. For most browsers, when the target is not explicitly set, the browser default behavior is _self. See the table from w3cschool:

http://www.w3schools.com/tags/att_a_target.asp

Attribute Values
ValueDescription
_blankOpen the linked document in a new window or tab
_selfOpen the linked document in the same frame as it was clicked (this is default)
_parentOpen the linked document in the parent frameset
_topOpen the linked document in the full body of the window
framenameOpen the linked document in a named frame


The kicker is that Safari uses _blank as the default instead of self. The solution for web designers? Explicitly set the target attribute to _self for every anchor. A bit of a hassle, but the best way to ensure that a new window does not open up with each hyperlink click.