simoncurd / hula-lang

Hula is a simple scripting language for writing applications.

Hula-lang

Hula is a simple scripting language for writing applications.

The core language goals are:

• Readability - scripts should be readable without knowing the syntax
• Extensibility - it should be easy to plug in new functionality
• Flexibility - scripts can be modified without a build

Hula was designed for orchestrating underlying services. As such:

• Hula is good at object modelling and gluing together services
• Hula is poor at capturing business logic - this should live in underlying services

At present Hula is only compatible with Java-based codebases, but support for other languages could be added in the future.

Syntax

An example Hula script looks like this:

Set greeting="Hello, World!"
Echo $greeting

Hula scripts contain a set of statements which generally follow this structure:

Command parameter1Name=parameter1Value, parameter2Name=parameter2Value as returnVariable

In the above script:

• There are two statements which use the Set and Echo commands.
• greeting is a parameter passed into the Set command, with value "Hello, World!"
• $greeting is a reference to the greeting variable (created by the Set command).

Some commands support nested statements, as shown below:

Set names="Jeff,Jim,John"

# turns the CSV string into a list
Tokenise $names as nameList
Loop $nameList as name
   Echo "Hello, $name"
   
   If $name = "Jim"
       Echo "I had an Uncle Jim"
   End
End

For further information please see the Hula Language Guide.

How it works

Hula scripts are parsed into BeanShell which is interpreted at execution time. Conditional logic is parsed by Antlr.

Getting Started

Hula-lang is packaged as an project which you can import directly into eclipse.

Alternatively you can test Hula scripts using the supplied batch/shell scripts.

Windows:

Hula Greetings

Linux/Mac:

Hula.sh Greetings

Note:

• The test scripts live in test/scripts.
• Javadocs available at [http://simoncurd.github.io/hula-lang/javadoc/]

Latest Version

• Version 0.1.1

Roadmap

Key Features for future versions:

• Performance improvements
• A broader Command set

Contributing

• Please raise any issues in the github issue tracker

Author

• http://github.com/simoncurd

Copyright and License

[Apache 2 License]

Copyright 2013 Simon Curd [email protected]

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

[http://www.apache.org/licenses/LICENSE-2.0]

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.