1. Functions
  2. Packaging extensions
  3. Loading extensions

WarpScript™ Extension

WarpScript™ is fully extensible through a mechanism called extensions which modify the set of functions known to WarpScript™.

WarpScript™ extensions are Java classes extending io.warp10.warp.sdk.WarpScriptExtension. The getFunctions method of the base class should be overridden, it will return a map of function name to function instance that will modify the functions known to WarpScript™. Extension classes must have a parameter less constructor.

By associating a null value with a function name key the named function will be removed from WarpScript™ when the extension is registered.

The template for creating a WarpScript™ extension is available on github.


A WarpScript™ function is a Java class which extends NamedWarpScriptFunction and implement the WarpScriptStackFunction. This latter interface has a method named apply which is called with a stack as parameter. It is within this method that the function performs its actions, interacting with the stack.

Packaging extensions

The template for WarpScript™ extensions provides a build.gradle build file with a shadowJar task. This task will build a jar which will contain the compiled code for the extension with possible dependencies.

This jar should be placed in the class path known of the JVM launching Warp 10™. For example, it can be placed in the directory /path/to/warp10/lib.

Loading extensions

WarpScript™ extensions declared in the configuration are loaded at startup by Warp 10™.

The declaration of an extension is done either via the warpscript.extensions property which contains a comma separated list of class names to load, or, as a preferred solution via properties prefixed with warpscript.extension, each one declaring a single extension.

The value of each of those properties is the fully qualified name of the WarpScriptExtension class to instantiate.

// Comma separated list of WarpScriptExtension classes to instantiate to modify the defined WarpScript functions
warpscript.extensions = ext.TutorialExtension

// Or Individual extension
warpscript.extension.template = ext.TutorialExtension

If you prefix such name by a sorting key followed by #. This capability exists so you can control the order in which the extensions are loaded.

warpscript.extension.template1 = 1#ext.TutorialExtensionOne
warpscript.extension.template3 = 3#ext.TutorialExtensionThree
warpscript.extension.template2 = 2#ext.TutorialExtensionTwo

If the configuration file contains a property named after the fully qualified class name prefixed by warpscript.namespace., the value will be used as a prefix of the name under which functions will be registered within WarpScript™.

warpscript.extension.test = test.TestWarpScriptExtension
warpscript.namespace.test.TestWarpScriptExtension = foo.

will register all functions of the TestWarpScriptExtension with foo. prefixed.

Note that the name of the function will appear in error messages WITHOUT the namespace.