I was analysing Kotlin antlr grammar and I noticed few strange things. I wonder if anyone could explain why were they implemented this way: 1. WS is "-> channel(HIDDEN)", but NL is not. 2. Why fragment Hidden is needed? 3. Why fragment Hidden does not include NL? I found that, how "?:" and "!!" depend on this weird definition, but wouldn't it be cleaner to define them as separate tokens? (lexer grammar - https://github.com/Kotlin/kotlin-spec/blob/release/grammar/src/main/antlr/KotlinLexer.g4)

dunno about

?:

, but a prefix

!!bool

is legal, although pointless