Please note: The following instructions apply to Mac OS X 10.6 (Snow Leopard). I have an updated guide for how to install mcrypt on 10.7 (Lion).

mcrypt is a useful extension to PHP if you would like to support a wide range of encryption algorithms within your code.

This guide explains how you can enable install mcrypt, along with the PHP extension, on Mac OS X 10.6.

Xcode

The Xcode package installs the necessary versions of tools like autoconf which is needed during the PHP extension compilation process. Make sure you have at least Xcode v3.2 installed; the install package is available on the Snow Leopard install DVD under the “Optional Installs” folder.

libmcrypt

libmcrypt is the library that provides the encryption functions. We need to install this before building the PHP extension.

• Open up Terminal.app
• export CFLAGS="-arch x86_64"
• Download libmcrypt from sourceforge
• Unpack the archive somewhere
• cd libmcrypt
• ./configure --disable-shared
• make
• sudo make install

PHP Extension

Once we have libmcrypt installed, we can build the PHP extension.

• Download PHP 5.3.4 source (tar gz format)
• Unpack the archive and cd php-5.3.4/ext/mcrypt/
• phpize

You should see output similar to the following:

Configuring for:
PHP Api Version:         20090626
Zend Module Api No:      20090626
Zend Extension Api No:   220090626

• ./configure
• make
• sudo make install

On successful install, you will see the following message:

Installing shared extensions:     /usr/lib/php/extensions/no-debug-non-zts-20090626/

To enable the module, include the following line in your /etc/php.ini file:

extension = mcrypt.so

Finally, restart your Apache server:

sudo apachectl restart

And that’s it: you should now be able to utilise the functions, as detailed in the PHP mcrypt documentation.

    use MooseX::Declare;

    class BankAccount {
        has 'balance' => ( isa => 'Num', is => 'rw', default => 0 );

        method deposit (Num $amount) {
            $self->balance( $self->balance + $amount );
        }

        method withdraw (Num $amount) {
            my $current_balance = $self->balance();
            ( $current_balance >= $amount )
                || confess "Account overdrawn";
            $self->balance( $current_balance - $amount );
        }
    }

    class CheckingAccount extends BankAccount {
        has 'overdraft_account' => ( isa => 'BankAccount', is => 'rw' );

        before withdraw (Num $amount) {
            my $overdraft_amount = $amount - $self->balance();
            if ( $self->overdraft_account && $overdraft_amount > 0 ) {
                $self->overdraft_account->withdraw($overdraft_amount);
                $self->deposit($overdraft_amount);
            }
        }
    }

Firstly, yes, that is indeed Perl. Secondly, wow: it actually _looks_ like a class definition. And this was the big win for me, as anyone coming from a Java or PHP background will find it trivial to understand what’s going on here. The main point is that by using MooseX::Declare, you are moving towards a more declarative programming style describing _what_ the program should do rather than _how_ it should achieve it. So, no more unrolling `@_`

Links

• MooseX::Declare on CPAN
• Piers Cawley’s blog – Just A Summary

If it’s worth saving to a logfile, it’s worth showing in the user interface. This is the paradox: if the information you’re logging is at all valuable, it deserves to be surfaced in the application itself, not buried in an anonymous logfile somewhere. Even if it’s just for administrators. Logfiles are all too often where useful data goes to die, alone, unloved and ignored.

This fails to take into consideration the two very distinct types of error messages that an application should have: administrator focused and user focused. Both of these error messages can be triggered by the same error condition. A problem occurs when you display administrator focused messages to the user: anyone that has come across largely meaningless error codes rather than a friendly human-readable language has experienced this less-than-valuable approach to logging.

Good error messages are essential to any application, and so are adminstrator focused messages, but let’s remember these are two very distinct features and need to be separated as necessary.

• The Complete History of the Perle Mongers of Olde London Towne – Dave Cross
• DBIx::Class for (advanced) beginners‎ – Leo Lapworth
• closures for fun and maybe profit‎ – David Cantrell
• Catalyst, DBIx::Class and PostgreSQL -‎ Matt Trout
• ‎Introduction to Moose – Mike Whitaker

In particular, DBIx::Class caught my eye as a nice way of abstracting database details behind more friendly object methods. Although, as the list of contributors shows, this is a highly complex problem to solve and achieving a “one size fits all” solution may be unrealistic.

Matt Trout’s talk was a little disappointing. Although I admired his passion and enthusiasm, there was far too much crammed in the 40 minute talk. Just concentrating on one aspect of the development process would been more useful. However, saying that, he did enough to convince me that I need to revisit PostgreSQL at some point in the future.

My colleague Mike Whitaker talked about the “postmodern object system”, Moose. There was lots of questions by the end of the talk, which was a good sign that the introduction had achieved its aim.

Overall, a good experience and a reminder that the Perl community is very much alive and well.

• London Perl Workshop

I played around with it many years ago after being inspired by Eric S. Raymond’s seminal article, “How to Become A Hacker” in which he explained that “getting” Lisp is equalivent to finding programming nirvana.

Whilst I didn’t quite reach those levels, I found that using Lisp was a great learning experience. Despite it being half a century old, it is still a relevant language today; the online Practical Common Lisp book contains examples of a spam filter, an ID3 tag parser and other real-world examples.

The following two links are for the curious who might wish to try it out:

• Ready Lisp: Common Lisp for Mac OS X
• Practical Common Lisp

The London Perl Workshop is a free one-day conference in central London, UK. It will be held on Saturday the 29th of November, 2008 at Westminster University’s New Cavendish Campus

I’ll be attending, and so will my friend and fellow Yahoo Mike Whitaker, who will be presenting some talks on Moose and Enlightened Perl.

• London Perl Workshop

Epigrams on Programming

Whenever you are tempted to type something into a print statement or a debugger expression, write it as a test instead.

The PHPUnit manual is really well written, and contains a great guide for writing your first tests.

It’s been simplified a lot since the last version, but the really big change is that it is now a modeless window. This means that the Find/Replace window can be left open whilst still allowing interaction with document windows. Initially, this seemed like a good feature to me before I realised a side-effect of this change: there are no keyboard shortcuts for the Find/Replace options anymore. You can see the difference by looking at the old Find/Replace window:

In this example, the Command key is being held down to illustrate which shortcuts are available; for example, Command-G toggles the Grep support.

Because of the Modeless window, these shortcuts have been lost in BBEdit 9. This makes the Find/Replace window slightly more cumbersome to use as turning on search options now requires the mouse. Furthermore, the very useful Start At Top option, has been removed completely.

Update: Thanks to Rich Siegel, CEO of Bare Bones Software, who has pointed me towards the release notes which document some brand-new Find shortcuts, thus rendering this blog post mostly pointless. Hurrah!

• Root Cause of Singletons
• Top 10 things which make your code hard to test