Inconsistent regex between Live Preview and JFlex Generator #385
Description
Regular expressions are incosistent between Live Preview and JFlex Generator.
Especially some Unicode character classes are not supported in Live Preview.
For example:
IDENT = 'regexp:[$_\p{ID_Start}][$\p{ID_Continue}]*'
IDE says it's an unknown character category.
It's not recognised on Live Preview, annotating there's a syntax error.
However, generating lexer (from generated flex file from the bnf) completes successfully.
The regex works in the plugin as well!
