carnelian - a ruby code generator tool

"Become what you are... a meta programmer"

Carnelian is inspired by T4 (http://en.wikipedia.org/wiki/Text_Template_Transformation_Toolkit)

Carnelian wants to be

1. Simple
2. Agnostic
3. Powerful
4. Lightweight
5. Free

By simple we mean that Carnelian should be understandable by almost anyone.

By agnostic we mean that Carnelian should be able to generate code for any text-based

By powerful we mean that Carnelian should be able to solve a big class of problems

By lightweight we mean that Carnelian should be able to execute from the command-line without the need of an IDE

By free we mean that Carnelian should be free to use and abuse with no strings attached

Using Carnelian

Carnelian is a ruby gem that requires ruby/1.9.3+

gem install --user carnelian

A silly example

Create a file named silly.mp containing:

@@@ metaprogram
@@@ extension cs
class SomeClass
{
@@> for iter in 0..10
    public int X@@=iter=@@ {get; set; }
@@> end
}

Then create a file named run.rb containing:

require 'carnelian/executor'

CarnelianExecutor.execute_metaprogram_to_file "silly.mp"

Execute the carnelian meta program by executing in a shell ruby run.rb

This will produce a file named silly.cs containing

class SomeClass
{
    public int X0 {get; set; }
    public int X1 {get; set; }
    public int X2 {get; set; }
    public int X3 {get; set; }
    public int X4 {get; set; }
    public int X5 {get; set; }
    public int X6 {get; set; }
    public int X7 {get; set; }
    public int X8 {get; set; }
    public int X9 {get; set; }
    public int X10 {get; set; }
}

Although simple silly as Carnelian is based on ruby it can generate code from XML, Database schemas, JSON giving the user power and flexibility.

We have used T4 and Carnelian to generate: TSQL, C#, C++, Java, XML

For more interesting samples see: https://github.com/mrange/carnelian/tree/master/src/samples/csharp

Available Carnelian tags

1. @@@ - Preprocessor tag, used to affect the code generation behavior
2. @@> - Template tag, used to write template code
3. @@+ - Code tag, used to write code outside the main template loop. Useful for creating support functions/classes
4. @@=ruby_expression=@@ - Inject tag, used to inject the ruby_expression into the output text

Available Carnelian preprocessor tags

1. @@@ metaprogram - The first line in a valid Carnelian meta program
2. @@@ require ruby_package - Adds require 'ruby_package' to the meta program
3. @@@ extension cs - The extension of the generated file (can be overriden)
4. @@@ include meta_program.mp - Includes a Carnelian meta program, similar to require in ruby
5. @@@ inject_tokens begin end - Advanced: Allows overriding of the inject tokens (default @@=, =@@), used id odd cases

If you happen to use sublime there's a carnelian sublime plugin: https://github.com/mrange/carnelian/tree/master/src/sublime

By the way - The Carnelian Gem is roughly 7 kib.