Region Support

[wa8f7192]

Hi Team,

Do you have an example on how to create a grammar file that supports region?
Like the one we see in c sharp in monaco editor

https://microsoft.github.io/monaco-editor/

[msujew]

Hey @wa8f7192,

there are two ways of accomplishing this, depending on your use case:

1. You create a StartRegion: '#region' name=ID; and EndRegion: {infer EndRegion} '#endregion'; rule and add them as possible statements at any level in the grammar (i.e. in C#, outside of classes, inside of classes or inside of methods). Then override the FoldingProvider to collect these elements and match each StartRegion to a EndRegion element to create the actual foldings.
2. This is quite bit more complicated, and I'm only outlining this: Instead of creating grammar rules, you would only create the respective lexer token types, and after the lexing (but before the actual parsing takes place), you would remove those tokens from the parser input and perform a bit of processing to perform the start and endregion matching. You then feed this data somehow back into the FoldingProvider. This has the benefit of being independent of your grammar shape, but the implementation is much more complicated.