Macro tokenizer 

tokenizer!() { /* proc-macro */ }

Parse a tokenizer DSL, where three kinds of statements are admitted:

• IDENTIFIER: a valid Rust identified used to give a name to the Tokenizer and related internal types
• "regex" => Type: “regex” is a valid regular expression, Type is a valid Rust identifier. Tokens that match the regex will be considered of type Type
• "regex" => _: “regex” is a valid regular expression and tokens that match it are considered separators and ignored.

Examples

tokenizer! {
    Test

    r"[a-zA-Z]\w*" => Identifier
    r"\d+" => Number
    r"\s+" => _
}