Linoleum

Perl: reading from a string, as if it was a file

nospam@example.com (Paul) — Wed, 04 Nov 2009 07:51:00 +1100

This seems fairly obvious, but somehow, even after fifteen years of Perl exposure, I've only just cottoned on to it now, so presumably this might be of assistance to other people.

Recently, I needed to read data line by line from a string (rather than from a file). You'd think that this would be a fairly common requirement, but evidently I've managed to either avoid it or fudge it up until now.

Anyway, there was no getting around it this time, but it turns out to be rather simple - just pass a reference to the variable when calling open():

my $text = "Some long text"; open(TEXT,"<", \$text); while(<TEXT>) { # do whatever } close(TEXT);

That's all there is to it!

Potential language changes for JDK7

nospam@example.com (Paul) — Mon, 02 Mar 2009 15:17:00 +1100

Jeremy Manson summarises some changes to the Java language that have been proposed as a result of a call by Sun for submissions.

How to build a Facebook app in Django

nospam@example.com (Paul) — Wed, 25 Feb 2009 21:18:00 +1100

From the Usawaretech Blog comes this incredibly detailed tutorial on using Django to write applications for Facebook.

It gives a brief overview on how Facebook applications communicate with the server, walks through setting up the application api key, and then launches into the main thrust of writing an application. This is a very good starting point for anyone looking to write their first Facebook application.

Scripting with Guile

nospam@example.com (Paul) — Tue, 24 Feb 2009 11:08:00 +1100

Developerworks are running an article on scripting with Guile, a Scheme interpreter and virtual machine.

There's a brief scheme tutorial, followed by a section on embedding scheme into C programs, and then a section on calling C functions from scheme scripts.

Python 3 Primer

nospam@example.com (Paul) — Sun, 22 Feb 2009 18:45:00 +1100

Developerworks are running a comprehensive series on Python version 3, and the changes that it brings with it.

Part one looks at print() - which is now a function, not a statement, and therefore requires parentheses. This, on its own, is going to cause a large number of pre-existing Python programs to break. It also covers the renaming of raw_input() to input, the new bytes literal, changes to string formatting and new I/O mechanisms.

Part two covers class decorators, metaclasses, abstract base classes, changes to exception handling and the handling of integer literals.

If you do any sort of Python programming, then you'd do well to read these two articles, as Python 3 is here now, and you're likely to be using it in the near future.

A Beginner's Introduction to Perl Web Programming

nospam@example.com (Paul) — Sun, 22 Feb 2009 10:28:00 +1100

O'Reilly have published an introductory article on web programming using perl - in short, CGI.pm for newcomers.

Five features that Perl needs

nospam@example.com (Paul) — Fri, 12 Dec 2008 06:56:24 +1100

As Perl rapidly approaches its 21st birthday, O'Reilly have published a write-up of five improvements that could be made to perl, ranging from greater frequency of releases to a light version of mod-perl.

Using readline with python

nospam@example.com (Paul) — Thu, 11 Dec 2008 08:53:00 +1100

GNU readline is a library that provides command-line editing facilities, such being able to browse through history with the cursor up/down keys - most Linux users would have seen this at the bash command line. It's also possible to include these features in your own Python programs, using Python's readline module. This article from O'Reilly explains how to do this, and gives a few good examples.

Init Call Mechanism in the Linux Kernel

nospam@example.com (Paul) — Fri, 05 Dec 2008 15:32:00 +1100

Andrew Murray, writing in the latest edition of Linux Gazette, examines Linux's driver initialisation mechanism.

Python 3.0 released

nospam@example.com (Paul) — Thu, 04 Dec 2008 15:01:00 +1100

Python 3.0 has been released.

You can get your copy here.

Using the bash debugger

nospam@example.com (Paul) — Thu, 27 Nov 2008 09:25:00 +1100

It's not widely known that bash has its own debugger - possibly because most Linux distributions don't install it by default. Linux.com show how to install it, and show a number of examples of using it to debug your own scripts.

Convoluted Column Arithmetic Examples Using Awk On Linux Or Unix

nospam@example.com (Paul) — Wed, 26 Nov 2008 12:06:00 +1100

Mike Tremell discusses some methods for performing column arithmetic using awk, in his Linux and Unix Menagerie weblog.

GCC hacks in the Linux kernel

nospam@example.com (Paul) — Tue, 25 Nov 2008 14:28:00 +1100

Tim Jones has written an article on the gcc extensions that are used within the Linux kernel, such as zero-length arrays (normally arrays must have at least one element defined), type discovery, ranges within switch/case blocks and prefetching.

Avoiding Memory Allocation

nospam@example.com (Paul) — Mon, 24 Nov 2008 09:54:00 +1100

Bojan Nikolic discusses a way to avoid memory allocation when coding in C++.

Examining the compilation process, part 3

nospam@example.com (Paul) — Sun, 23 Nov 2008 08:11:00 +1100

Part three of Linux Journal's look at the compilation process has been published, this time with an introduction to the make utility.