This afternoon I created an Eclipse editor for WebDSL from just its syntax definition using Spoofax/IMP in a matter of minutes. The editor provides syntactic editor services such as syntax highlighting, folding, outlining, error recovery; all out of the box. Here’s a screenshot with an impression.
Note how my decision to include ‘sections’ in WebDSL turns out to play very nice with code folding. Spoofax/IMP also supports semantic error services such as displaying type check errors and cross-references, but that requires the WebDSL compiler to be refactored from a batch compiler to an incremental compiler.