More syntax: tips and tricks

Comments

Comments are marked with '#'. Everything from # to the end of a line is ignored:

expression -> number "+" number # sum of two numbers

Charsets

You can use valid RegExp charsets in a rule (unless you're using a tokenizer):

not_a_letter -> [^a-zA-Z]

The . character can be used to represent any character.

Case-insensitive string literals

You can create case-insensitive string literals by adding an i after the string literal:

cow -> "cow"i # matches CoW, COW, and so on.

Note that if you are using a lexer, your lexer should use the i flag in its regexes instead. That is, if you are using a lexer, you should not use the i suffix in nearley.