Improve the testability of lexing (`CustomLexer`) and parsing functions so they can be tested individually. Currently, a `CustomLexerContext` or `ParserContext` is needed but they can't be easily created on their own.
Improve the testability of lexing (
CustomLexer) and parsing functions so they can be tested individually.Currently, a
CustomLexerContextorParserContextis needed but they can't be easily created on their own.