Well - do you want to be good at parsing/has any need for it? Even if you write your own programming language you are much better off using something like ANTLR

Well - do you want to be good at parsing/has any need for it? Even if you write your own programming language you are much better off using something like ANTLR to generate your grammar — the advantage is a well-specified standard description of your own grammar and no parser bugs. Though mind you, not everyone shares my sentiment here, last time I wrote that people were adamant about hand-written parsers.