How to hide custom terminals in a rule

[ydaveluy]

Hello,

I would like to disable the WS terminal rule in a custom rule to prevent whitespaces between elements.
In Xtext it was possible to use the following syntax which is accepted by langium but does not seems to work:

ARuleWithoutWS hidden(Ml_COMMENT, SL_COMMENT): ...;

Here is an example of what I would like to achieve (2 differents paths instead of only one on 2 lines) :
https://langium.org/playground?grammar=OYJwhgthYgBAEgUwDbIPYHU0mQEwFD6IB2ALiAJ6wAKYpAFgM4Bc%2Bs7sADnUwNQC8tBgCoA3ISH1Y9AJa5cJWAAoAsgBkA%2BgGEA8ipUBRAHIAVADSwAypt37jJgJSsOygOQB6V7EaJgEEqQCAJIAIg684oSy8oqkiCAQMsRgyLAYlsyw7gA6jLzu4nEJSSmwoZnuANoaYAC0AF4AgrUAWgC6ldkA7hptwgVRcgrEsEWJyanq2nqGphXZOcKdjNmWfQD82cILA9HDo-HjpdbTdnNZCwuVAHrZxNkgfQNAA&content=AQeghiAOYC4BYFgBQowDsQHt4FMBOUscQA

Any idea ?

[msujew]

Hey @ydaveluy,

Langium replaced the per-grammar/rule hidden terminals with a global hidden flag on the terminal itself:

hidden terminal WS: ...;

Due to limitations in our parsing library (Chevrotain), it's not possible to do the same as Xtext/Antlr did. You could however implement this via lexer modes in Chevrotain by overriding the TokenBuilder.