Moo tracks detailed information about the input for you. It will track line numbers, as long as you apply the lineBreaks: true option to any tokens which might contain newlines. Moo will try to warn you if you forget to do this.

Moves the lexer to a new state, and pushes the old state onto the stack.

Returns to a previous state, by removing one or more states from the stack.

Moves to a new state, but does not affect the stack.

You can have a token type that both matches tokens and contains error values.

Moo doesn't allow capturing groups, but you can supply a transform function, value(), which will be called on the value before storing it in the Token object.

Used for mapping one set of types to another. See https://github.com/no-context/moo#keywords for an example