How to add a new jar file to the Scala REPL classpath (interactive command line)

Scala REPL FAQ: How do I add a Jar file to the Scala REPL classpath? (The Scala REPL is the interactive command line you get if you just type scala at your command line.)

To add a new jar file to the Scala REPL classpath (interactive command line classpath), use the :require command at the command line, like this:

scala> :require myjar.jar

CakePHP require, notEmpty, allowEmpty, and form validation

CakePHP require, notEmpty, and allowEmpty FAQ: Help, I'm trying to edit my CakePHP model $validate field to make sure a CakePHP form field is required, but 'require' doesn't seem to be working as expected.

After fighting with a CakePHP form I just got this information beat into my head, so I thought I'd share it here. In short, if you want to make a CakePHP form field required, what you really want to use is the CakePHP notEmpty rule, like this:

PHP cannot redeclare function error message

PHP function FAQ: Help, I'm getting a PHP cannot redeclare function error message, how do I fix it?

Assuming you don't really have two PHP functions defined with the same name, this "cannot redeclare" function error message is usually caused by using the require or include functions to include the same common file (and therefore its functions) more than once.

A JRuby jar include tip

Ever need to include a Java jar file in a JRuby script? As I work to convert my Mac speech recognition server to JRuby, the first task I need to tackle is to include the Sphinx-4 jar files in my JRuby path. You can include one Java jar file in your JRuby script path very easily, like this:

require 'lib/sphinx4.jar'

where the jar file 'sphinx4.jar' is in a local subdirectory named lib, which is cool. But if you need to include many Java jar files into your JRuby script at one time, here's a very cool way to do that:

Ruby NameError: uninitialized constant error message

Problem: When working with some Ruby code in an irb session, I just got the following error message:

NameError: uninitialized constant Tempfile

Here's a snippet of my irb session where this error occurred:

>> tmp =
NameError: uninitialized constant Tempfile
	from (irb):1


This "NameError: uninitialized constant" looks intimidating, but it's actually not a big deal: I just forgot to require the tempfile package.