如何从antlr词法分析器中提取关键字

Question

I am building a text-editor in Java for a grammar that I did not write and I would like to support syntax highlighting. I have a lexer file with keywords in it (the following is a subset):

DATABASE: 'DATABASE';
NATIVE: 'NATIVE' -> mode(NATIVE_QUERY);
SOURCE: 'SOURCE';
CHECK: 'CHECK';
ACTION: 'ACTION';
EXECUTE: 'EXECUTE';
USING: 'USING';
ON: 'ON';
EACH: 'EACH';
FROM: 'FROM';

I would like to dynamically read these keywords to use for syntax highlighting of those keywords in the text-editor I am making. I currently am doing this manually but I want the text-editor to do it dynamically in case the authors change the lexer. How do I do this? Is this the right way to go about it?

Answer 1

I don't think there's an attribution mechanism in Antlr itself to tag "keywords", but that's what you should read up on. In lieu of that, you could apply a hack that assumes an order within the grammar whereby you define the first and last rules for keywords "DATABASE" and "FROM". Then, write a method to go through the ruleNames[] array which you can call anytime to accumulating all the keyword names between the first and last rule names you defined above. To make this work you would have to write some comments that say something like "// On severe penalty, only add keyword productions in rules between "DATABASE" and "FROM". However, Antlr lexer rules are ordered for matching preference, so this hack may not work.