EAG - VS Code Language Extension for Extended Affix Grammar Specifications

This is the VS Code language extension "epsilon-eag" for the grammar specifcation language of Epsilon/Gamma Extended Affix Grammars.

The compiler generator processing these specifications was originally developed under the name Epsilon in Oberon-2 and later migrated to D. Afterwards the development was continued in the Gamma project.

The language server has been developed using the Xtext language framework to realize name navigation, auto-completion and cross reference resolution. It is backed by the real compiler generator (which performs deeper semantic checks and DLang code generation on file saving). The Gamma compiler generator is embedded into the VS code extension. If DMD is installed, the extension automatically triggers the compilation of the generated compiler sources.

Syntax highlighting support has been developed using the syntax hightlighting "grammar" online editor Iro capable to issue "grammars" for Textmate, Atom, Sublime and others. For details see Chris Ainsley's article about it.

In case of Textmate, Iro creates .plist files. As it is more convinient and more common to use Textmate grammars in JSON format, the .plist file has been transformed using the service http://json2plist.sinaapp.com/.

The Iro file for syntax hightlighting definitions may be found at Epsilon.iro.

Features

Currrently the following features are supported:

• syntax highlighting (please install the themes Epsilon EAG (Light) or Epsilon EAG (Dark) for best coloring)
• folding
• auto bracket closing and insertion
• syntax and reference errors for meta and hyper nonterminal
• nonterminal navigation
• auto-completion
• auto-indentation
• semantic checks by the real Gamma compiler generator which comes embedded in the extension, with position-correct findings shown in the problem report view (on file saving)
• embedded Gamma compiler generator runs on
  • Windows 64-bit
  • Linux 64-bit
  • MacOS
• source code generation of the target language compiler on file saving (if no errors have been found), available in build sub folder
• automatic compiling of the generated compiler D source code with DMD, if installed, available in the build sub folder

Requirements

Requires Java 8 or Java 11 to run the language server. Does not run on Java 17 (Xtext restriction).

It is recommended to install DMD D-Lang compiler (currently in version 2.103.1) for utilizing the feature of automatically compiling the target language compiler.

Extension Settings

See VS code settings [Ctr+,], look up for 'eag'.

Known Issues

The error positions of the generated target language compilers are not accurate under circumstances. See [Gamma issue #6](https://github.com/linkrope/gamma/issues/6).

Release Notes

See CHANGELOG