How to match a string, but case-insensitively?

Question

Let\'s say that I want to match \"beer\", but don\'t care about case sensitivity.

Currently I am defining a token to be (\'b\'|\'B\' \'e\'|\'E\' \'e\'|\'E\' \'r\'|

Answer 1

Define case-insensitive tokens with

BEER: [Bb] [Ee] [Ee] [Rr];