(if you don’t read my blog for the geeky thrill of it, you may want to give this post a miss ;))

Follow my little IRB session, if you will:

>> nil or "val"
=> "val"

>> puts (nil or "val").inspect
=> "val"

>> x = nil || "val"
=> "val"

>> x
=> "val"

>> y = nil or "val"
=> "val"

(wait for it…)

>> y
=> nil

Seriously, ruby. What the crap?

Okay, so I just figured out what’s going on here. “or” works both as a logic operator and a conditional statement. Just like you can do:

x = something_dangerous() rescue "x failed!"

and

puts "x is greater than 10" if x > 10

It would seem you can also do

x = some_value or puts "i guess the assignment didn't evaluate to true"

Meaning that in my example above:

y = nil or "val"

Ruby evaluates it as:

(y = nil) or ("val")

(i.e. in the second set of brackets, y is not actually assigned to anything)

Of course, || is solely a logic operator. Which is why it looks like you get different behaviour when you use || instead of or.

When I found out about ruby supporting both sets of logic operators (&&, ||, !) and (and, or, not), I thought it was dumb, but just a matter of preference which type you prefer.

When I found out that the symbol-based ones bind tighter than the keywords, I winced a little and noted to myself never to rely on that, because it’s neither readable or obvious.

Now that I’ve stumbled upon this latest gem of knowledge, It just makes me cringe…

Pay attention to the output types, kids:

>> { "key" => "val" }.reject { false }
=> {"key" => "val"}

looking good so far...

>> { "key" => "val" }.select { true }
=> [["key", "val"]]

eww... what?

Given the integration of PDF into Mac OS X, I was surprised to find that there didn’t seem to be any tool to convert HTML files into PDFs. So, like any frustrated coder I wrote my own little script to do it: html2pdf.py

Requires python and OSX 10.5 (Leopard). It uses a WebKit view for the rendering, so in theory it should work with any URL that safari can handle - but I haven’t exactly tested it thoroughly…

In any OSX “document window”, there is a little icon representing the current document. If you click and hold this icon, it becomes a draggable alias for the file. You can then use that alias much as you would the file itself (as if you had dragged it from the finder) - but one thing you can’t do is delete the file by dropping it in the trash.

Trashy is a simple program to fix that. Put it in your dock, and it will send anything you drag onto it into the trash. Click here to download Trashy.

Here’s the entire source code applescript, if you’re curious (or just naturally suspicious of running random programs you found on internet, as you ought to be):

on open fileList
	tell application "Finder"
		repeat with f in fileList
			set n to 0
			repeat while class of f is alias file
				if n is less than 5 then
					set n to n + 1
					set f to original item of f
				end if
			end repeat
			move f to the trash
		end repeat
	end tell
end open

on run
	tell application "Finder" to open the trash
end run

[I made this]

A Lightweight Metadata manager for OSX, allowing you to easily tag and rate any type of file (which is then indexed by spotlight). This is basically my iPhoto replacement now, after spending a week trying to fix its broken database, orphan files, duplicates and all that rubbish. This is much simpler, and it can be used to tag any type of file I want.

This is the result of 2 days work, and just 400 lines of code. That’s pretty decent in my book, the combination of python and cocoa is a pretty powerful beast. Once you get past all the runtime errors and pyobjc bridge troubles, that is…

(view link)

According to matt, I just made milk come out of Python’s nose.

[i made this, although I’m hardly proud of that fact]

For those who care (or are thoroughly confused), this is a python function to find out where an alias file (the mac’s version of a shortcut or soft link) actually points to. And no, it really shouldn’t have to be this hard.