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use super::Symbol;
use alloc::{boxed::Box, string::String, string::ToString, vec::Vec};
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum Binder {
Lam,
Pi,
}
pub type BTerm = Box<Term>;
pub type Arg = crate::Arg<String, BTerm>;
pub type OptArg = crate::Arg<String, Option<BTerm>>;
impl From<Term> for Arg {
fn from(ty: Term) -> Self {
let id = "$".to_string();
let ty = Box::new(ty);
Self { id, ty }
}
}
#[derive(Clone, Debug, Eq, PartialEq)]
pub enum Term {
Symb(Symbol),
Appl(BTerm, Vec<Term>),
Abst(OptArg, BTerm),
Prod(Arg, BTerm),
}
impl Term {
pub fn absts(self, args: impl Iterator<Item = Arg>) -> Self {
args.fold(self, |acc, arg| Self::Abst(arg.map_ty(Some), Box::new(acc)))
}
pub fn prods(self, args: impl Iterator<Item = Arg>) -> Self {
args.fold(self, |acc, arg| Self::Prod(arg, Box::new(acc)))
}
pub fn apply(mut self, mut args: Vec<Self>) -> Self {
if args.is_empty() {
self
} else {
match self {
Self::Appl(_, ref mut args1) => {
args1.append(&mut args);
self
}
_ => Self::Appl(Box::new(self), args),
}
}
}
}