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Warning The entire Impulse is deprecated starting Februari 1st, 2023. As the Rascal-eclipse project is deprecated, which is the only known use of Impulse, we are also deprecating this otherwise valuable project. It is a matter of software maintenance capacity of the community. DSL projects which depend on Impulse and Rascal-eclipse will be port{ed,able} to VScode support based on the Rascal-language-servers project.

IMPULSE

IMPULSE is a fork off the IDE Meta Tooling Plaform's core run-time on github which used to be part of an Eclipse IMP incubation project. The code was licensed open-source by IBM and other contributors under the EPL. The IMPULSE fork will not be backward compatible with old versions and focuses on:

  • Migrating deprecated API usage to E4 API
  • Removing dead code
  • Adding missing interaction features
  • All this while keeping as much of the investment in the IMPULSE run-time alive: a simple and effective language-oriented abstraction layer over lower-level Eclipse API.

Currently this fork is in the process of renaming packages and extension point to the UseTheSource and IMPULSE namespaces.

IMPULSE radically simplifies and speeds up the IDE development process in Eclipse, for both language with existing front-ends as well as languages generated using compiler and interpreter generation frameworks.

The IMPULSE is essentially a wrapper for Eclipse RCP and some JDT API that let's you focus on your language features as opposed to UI features. The core of the run-time is the UniversalEditor class which is a language parametric editor. By instantiating the UniversalEditor, using extension points, with information about your own language you can incrementally create a basic IDE. You provide this information mainly by implementing a number of simple interfaces.

IMPULSE is described (as IMP) in a 2009 OOPSLA paper

Extension points

The first and only absolutely necessary extension point to bind is "languageDescription". It makes your language known to Eclipse and triggers a special editor whenever a file with a particular extension is opened:

<extension point="io.usethesource.impulse.languageDescription">
      <language description="Hello" extensions=".ext" language="MyLanguage">
      </language>
   </extension>

The second most important extension point is "parser":

 <extension id="myparsecontroller" name="My Language parser" point="io.usethesource.impulse.parser">
      <parser class="org.mylanguage.MyParseController" language="MyLanguage">
      </parser>
   </extension>

This will force you to implement IParseController, a simple interface which allows you to call your own parser and return any kind of parse tree, abstract syntax tree or list of tokens. The point of IParseController is to be agnostic in what parsing technology you use or what kind of representation you have for the output of the parser. Hence the parse method in IParseController returns an object of type java.lang.Object. Downstream this same object will be passed to you again, for example when you want to add some syntax highlighting.

For now, my time is up describing impulse, but you may have gotten the gist of this now :-) Simply search for "impulse" in the editor of plugin.xml to discover more of the extension points of UniversalEditor. It includes features for outline, highlighting, menu options, etc.

IMPULSE is not perfect, but it gives you a head start in developing an IDE without too much fuss, and it does not assume much about the way you want to deal with your own language, except of course that you have a JVM :-)