lexer foo_lexer {

    @trivia()
    whitespace <- p"[ \n\r\t]+"

    family alphanumericals {
        def <- "def"
    }

    var <- "var"

    family alphanumericals {
        error <- "error"
        example <- "example"
        null_tok <- "null"
    }


    family punctuation {
        comma <- ","
        dot <- "."
        semicolon <- ";"
        l_par <- "("
        r_par <- ")"
        l_brace <- "{"
        r_brace <- "}"
        equal <- "="
        plus <- "+"
    }

    minus <- "-"
    less_than <- "<"

    @unparse_spacing(with=alphanumericals)
    family alphanumericals {
        number <- p"[0-9]+"
        @symbol()
        identifier <- p"[a-zA-Z_][a-zA-Z0-9_]*"
    }

    string <- p"\"[^\"]*\""

    family comments {
        @unparse_newline_after
        @trivia()
        comment <- p"#(.?)+"
    }

}