Lexer for highlighting language syntax given by BNF grammar?

Question

C++ / C#

Good day.
I wanted to implement syntax highlighting for the language using a lexer for this. The essence is simple, we find a token, we frame it with a set of symbols for a particular color. But the fact is that language tokens are described in BNF, and lex / flex work with regular expressions to write tokens. The question actually is how to build a lexer for the BNF grammar?

Answer 1

Are you confusing a token with a terminal/non-terminal? Because for lexical analysis and parsing into tokens, a grammar in the form of BNF is not needed. More precisely, it will be very simple - stupidly listing all the tokens.

Answer 2

This grammar is easily reduced to flex regular expressions.
a grammar parser is needed if you are going to highlight language constructs.
Well, in general, there is a bison for this, since you came from flex.