Use array_merge to concatenate two numerically-indexed arrays; not array_push and not the array union operator: +.

$first = array('doh', 'ray', 'me');
$second = array('fah', 'soh', 'lah', 'te', 'do');

echo "Union: ", var_export($first + $second, true), "n";
echo "Merge: ", var_export(array_merge($first, $second), true), "n";

// array_push returns int, not an array:
array_push($first, $second);
echo "Push: ", var_export($first, true), "n";

The output:

Union: array (
  0 => 'doh',
  1 => 'ray',
  2 => 'me',
  3 => 'te',
  4 => 'do',
)
Merge: array (
  0 => 'doh',
  1 => 'ray',
  2 => 'me',
  3 => 'fah',
  4 => 'soh',
  5 => 'lah',
  6 => 'te',
  7 => 'do',
)
Push: array (
  0 => 'doh',
  1 => 'ray',
  2 => 'me',
  3 =>
  array (
    0 => 'fah',
    1 => 'soh',
    2 => 'lah',
    3 => 'te',
    4 => 'do',
  ),
)

Once you know your currency codes, currency conversion couldn’t be simpler: 100 USD in GBP

And Maths? As well as your basic arithmetic operators, it also handles has pretty natural syntax for “to the power of”. e.g. (2143/22) ^ (1/4). Trigonometry function use radians, so it also lets you use PI as a constant: sin(PI/6)

They’ve even got a (really) nice way of handling percentages – you can even keep your commas and currencies in place – so calculating VAT is as simple as £4,399.99 * 17.5% (Note: I switched to the UK site for that one… If you run it on google.com the answer automatically gets converted to US dollars! Of course, they let you override that by adding ” in GBP” to the query string.)

You can do weight conversions, distances, storage capacity… the list goes on.

So how come they don’t do time conversion? I don’t mean minutes into days, I mean converting one time zone into another.

I’m looking forward to reading about Apple’s new Macbooks, and I know there’s a conference at 10AM Pacific Time, or 1PM Eastern Time… but I don’t know what time that is where I am. I’m gutted Google can’t handle 10AM PST IN GMT.

Oh well… I guess I’ll just have to wait.

Update: I’ve just discovered Google’s things-to-do page (UK only?) Amongst other things, it explains how to get the current time for any location: simply prefix the place-name with “time ” – e.g. time london. That may be helpful if you know your geography? Personally, I’ve no idea which cities are in PST, and I’d only be guessing that maybe New York is in EST? (Google says EDT for New York – is it daylight savings time at the moment?)

In fact, if you keep your eye on the github blog you’ll see a steady stream of well-known projects moving over to git, as diverse as the Blueprint CSS framework and the Haskell compiler.

Basically, if git was a stock-market commodity, analysts would be issuing strong buy recommendations left, right and centre. Git’s tipping-point has arrived.

How to play

If you’ve arrived here via search-engine, it’s probably because you’re trying to work around errors like Can’t locate Error.pm or Can’t locate SVN/Core.pm. Read on…

I already had macports installed, but if you haven’t, follow the macports install instructions – we’ll be using macports to download and install git as it’s supposed to be simpler than building from source.

If you’ve had macports installed a while, make sure it’s up to date:

$ sudo port selfupdate

We want to use git to connect to subversion repositories as well, so we’ll just check that’s possible:

$ port list variant:svn
git-core        @1.6.0  devel/git-core
subversion      @1.5.1  devel/subversion

I already had subversion installed but through trial-and-error found I needed to reinstall it with perl-bindings (git must be using perl scripts to talk to subversion…) Note: I’m using the -f flag to force it to reinstall, you might want to try without first, just to see what conflicts it brings up:

$ sudo port uninstall -f subversion-perlbindings
$ sudo port install -f subversion-perlbindings

Next, we install git:

# This may take a while to install with all its dependencies:
$ sudo port install git-core +svn

And finally, we check it works:

$ mkdir myproject; cd myproject;

# Check your PATH's set properly, this should output:
# fatal: Not a git repository
$ git svn

# If that's OK... clone a repository:
$ git svn clone http://example.com/svn/project/trunk

Can’t locate Error.pm

If you’re getting Can’t locate Error.pm or Can’t locate SVN/Core.pm you should immediately try:

$ PATH=/opt/local/bin:$PATH git svn

If that works, you know it’s just a PATH problem. It’s something to do with Apple’s perl install having slightly kooky ideas about where to store perl libraries.

If you’re still getting complaints about Error.pm, you need to install the CPAN module – and we’re going to use the /opt/local/bin instance of cpan, to make sure things go in the right place for us:

$ sudo /opt/local/bin/cpan -i lib::Error

Cross your fingers, and try again:

$ PATH=/opt/local/bin:$PATH
$ git svn clone http://example.com/svn/project/trunk

If things are working, git will spend a while cloning the subversion repository by pulling out every single revision so you can have a complete set of revisions (including deltas), ready for you to refer to with lightning-speed regardless of internet connectivity. Which is nice.

Today, I wrote a log message about centigrade and farenheit conversions, using the proper degree symbol °, but this triggered an encoding problem, resulting in an error message:

macbook:~/projects/smarty ash$ svn ci plugins/function.temperature.php
svn: Commit failed (details follow):
svn: Can't convert string from native encoding to 'UTF-8':
svn: Tweak: altered temperature title attribute so it contains both farenheight AND
centigrade.  e.g. "88?\194?\176F or 17?\194?\176C".  The order is switched depending on user
preference.
--This line, and those below, will be ignored--

M    function.temperature.php

svn: Your commit message was left in a temporary file:
svn:    '/Users/ash/projects/propagandr/smarty/plugins/svn-commit.tmp'

It didn’t take long to realize although my editor (vim) was configured to use UTF-8, the subversion command-line client had no way of knowing that.

One way of stopping this happening again would be to set my locale permanently so the character-type is UTF-8 (e.g. export LC_CTYPE=en.UTF-8.) But, as a short-term one-off fix, avoiding retyping the log message (and a little off-topic: remembering subversion ignores filenames mentioned in log messages, forcing you to reenter them on the command-line again) – the simple fix was:

ash$ LC_CTYPE=en_GB.UTF-8 svn ci -F plugins/svn-commit.tmp plugins/function.temperature.php

Worked like a charm.

ImageMagick is a great swiss-army-knife type tool, with a shed-load of options for converting and combining images. Unfortunately, the sheer number of options can make it a bit time-consuming and frustrating trying to find the one you want.

My aim was simple: given a PNG, make the whole thing semi-transparent.

Searching Google using “transparent” and “opacity” drew a blank – all I got was instructions on how to set transparency for certain colours – not what I wanted to do.

The word I was missing was “alpha”, and the magic incantation for changing the opacity of the whole image is:

convert input.png -channel Alpha -evaluate Divide 2 output.png

In my case, I wanted to set the PNG to be 50% transparent (hence “Divide 2″.) Of course, you can change that number to whatever works for you.