Macro alphabet::alphabet

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

Declares a constant alphabet. You can choose any valid identifier as the name for the alphabet.

Examples

Basic usage:

use alphabet_macro::alphabet;

alphabet!(BINARY  = "01");
alphabet!(ENGLISH = "abcdefghijklmnopqrstuvwxyz");
alphabet!(GERMAN  = "aäbcdefghijklmnoöpqrstuüvwxyzß");
alphabet!(HEBREW  = "אבגדהוזחטיכלמנסעפצקרשת");

assert_eq!(BINARY.len(), 2);
assert_eq!(ENGLISH.len(), 26);
assert_eq!(GERMAN.len(), 30);
assert_eq!(HEBREW.len(), 22);

You can also specify a visibility for the generated alphabet:

use alphabet_macro::alphabet;

alphabet!(pub BINARY = "01");

You can pass attributes to the generated alphabet as well. This includes doc comments, which internally use attributes:

use alphabet_macro::alphabet;

alphabet! {
    /// An alphabet for binary strings.
    pub BINARY = "01";
}

Syntax

Alphabets follow the following syntax, with the nonterminal alphabet being the contents of the alphabet! macro:

alphabet ::= attribute* visibility? identifier "=" literal-string ";"?