derive finite automaton

A procedural macro for building a finite automaton. Main use is for lexing multiple character wide tokens see derive-finite-automaton/examples/main.rs.

Run example:

shell cd derive-finite-automaton cargo run --example main

View example macro expansion (requires cargo-expand):

shell cd derive-finite-automaton cargo expand --example main

Example

```rust use derivefiniteautomaton::{FiniteAutomata, FiniteAutomataConstructor};

[derive(FiniteAutomataConstructor, Debug, PartialEq)]

[automaton_mappings(

"{" => Tokens::OpenBrace,
"}" => Tokens::CloseBrace,
"=" => Tokens::Assign,
"=>" => Tokens::ArrowFunction,
"==" => Tokens::Equal,
"===" => Tokens::StrictEqual,
"." => Tokens::Dot,
"..." => Tokens::Spread,

)] pub enum Tokens { OpenBrace, CloseBrace, ArrowFunction, Equal, StrictEqual, Assign, Dot, Spread, } ```

You can add conditional mappings with the following

```rust use derivefiniteautomaton::FiniteAutomataConstructor;

[derive(Debug, FiniteAutomataConstructor)]

[automaton_mappings(

"{" => Tokens::OpenBrace,
"}" => Tokens::CloseBrace,
"=>" => Tokens::ArrowFunction,
"==" => Tokens::Equal,
"===" => Tokens::StrictEqual,
"=" => Tokens::Assign,
// Some mapping
"." => Tokens::Dot,

)]

[cfgattr(feature = "special", automatonmappings(

".?." => Tokens::Magic,

))] pub enum Tokens { OpenBrace, CloseBrace, ArrowFunction, Equal, StrictEqual, Assign, Dot, #[cfg(feature = "special")] Magic, } ```