Lexer rule can I create a token by doing a dynamic lookup of a list of values?
eg

CHEMICALNAME: {getAllChemicalNames());

Here if the string passed in is A LIQUID HYDROGEN PUMP then after processing 'A' LIQUID HYDROGEN should be a single token as getChemicalNames() is a list which contains liquid hydrogen.

How do I populate a list of literals which is dynamic so that if it occurs in a string it is considered as a single token?