# Eta Combinator Core (no_std)
Rust implementation of my structural calculus.
## Basic Usage
```rs
use eta_core::basic::runner; /* import */
let mut out = String::new(); /* create output string for reuse */
runner(&mut out, &input); /* run the runner */
print!("{out}"); /* use it however */
```
## Advanced Usage
```rs
use eta_core::{human::*, theory::*}; /* import */
/* create new human readable name dictionary */
let mut dict = Dict::new();
/* run the parser */
let inp = match parse(input, &mut dict) {
Ok(k) => k,
Err(e) => {
let _ = write!(out, "parse error at byte {}: {}\n", e.byte, e.msg);
return;
}
};
/* default/baisc lore */
/* (you may create your own lore using eta_core::theory) */
/* you may also create bring your zeta extentions! (using Kind::try_from((zeta_fn, ID))) */
let mut exp = lore(Kind::from((inp, lore_end())));
match eta(&mut exp) {
Ok(res) => { let _ = write!(out, "[^] {}\n", unparse(&res, &dict)); } /* (eta could not be consumed) */
Err(res) => { let _ = write!(out, "[H] {}\n", unparse(&res, &dict)); } /* halt (eta is consumed) */
}
```
## Lambda Calculus
Lambda calculus can be implemented as a sub-calculus of Eta.
```lisp
((E ((A A) E)) ;main
;Lx
(E (
(P (E
;Px
;lambda calculus expression here
;note: P is application, A is abstraction as we have set up here
(P ((A (x (x x))) x))
;/lambda
;/Px
))
;Pi
(
((A (n b)) x)
(E ((n b) x))
)
;/Pi
))
;/Lx
) ;/main
```
> Documentation under heavy WIP.