I haven't used parsec but I have used fparsec and I found that usage of the "operator precedence parser" was very useful in parsing expressions. It also sped up

I haven't used parsec but I have used fparsec and I found that usage of the "operator precedence parser" was very useful in parsing expressions. It also sped up parsing a lot. As for BNF, it is like a standard that your parser should follow. A map for when parsing gets complex. You may not need it for a simple parser.