Sunday, June 20, 2010

New In Xtext: Case Insensitive Languages

A quick glimpse at the New and Noteworthy features of Xtext 1.0 reveals that the framework allows to develop languages that are case insensitive.
To mark upper and lower cases meaningless for keywords or cross references, you just have to replace two default fragments in the MWE2 workflow, add an option and hit the Run button:

The o.e.x.g.parser.antlr.ex.rt.AntlrGeneratorFragment and replace the two fragments, that are configured by default: o.e.x.g.parser.antlr.XtextAntlrGeneratorFragment and o.e.x.g.parser.antlr.XtextAntlrUiGeneratorFragment.

Xtext provides an API that allows to define custom, local scopes that are ignore case as well. Have a look at the utility class o.e.x.resource.ignorecase.IgnoreCaseScopes to learn more about it. The configured generator fragments will take care of the rest, e.g. the default bindings for the global scopes, the parser and the serializer.

As you can see it is possible to define case insensitivity independently for keywords and cross-links. And if you want to keep your workflow short and concise instead of adding this flag for each and every fragment that accepts this option, you are free to introduce a new property and use this one directly or via the auto-inject option. Please refer to the updated documentation if you want to learn more about the MWE2 language.

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