use clvkr::{Allocator, Atom, NodePtr, allocator::SExp};
use num_bigint::BigInt;
use crate::{
FromClvk, FromClvkError, MatchByte, destructure_list, destructure_quote, match_list,
match_quote,
};
pub trait ClvkDecoder: Sized {
type Node: Clone + FromClvk<Self>;
fn decode_atom(&self, node: &Self::Node) -> Result<Atom<'_>, FromClvkError>;
fn decode_pair(&self, node: &Self::Node) -> Result<(Self::Node, Self::Node), FromClvkError>;
fn decode_bigint(&self, node: &Self::Node) -> Result<BigInt, FromClvkError> {
let atom = self.decode_atom(node)?;
Ok(BigInt::from_signed_bytes_be(atom.as_ref()))
}
fn decode_curried_arg(
&self,
node: &Self::Node,
) -> Result<(Self::Node, Self::Node), FromClvkError> {
let destructure_list!(_, destructure_quote!(first), rest) =
<match_list!(MatchByte<4>, match_quote!(Self::Node), Self::Node)>::from_clvk(
self,
node.clone(),
)?;
Ok((first, rest))
}
fn clone_node(&self, node: &Self::Node) -> Self::Node {
node.clone()
}
}
impl ClvkDecoder for Allocator {
type Node = NodePtr;
fn decode_atom(&self, node: &Self::Node) -> Result<Atom<'_>, FromClvkError> {
if let SExp::Atom = self.sexp(*node) {
Ok(self.atom(*node))
} else {
Err(FromClvkError::ExpectedAtom)
}
}
fn decode_pair(&self, node: &Self::Node) -> Result<(Self::Node, Self::Node), FromClvkError> {
if let SExp::Pair(first, rest) = self.sexp(*node) {
Ok((first, rest))
} else {
Err(FromClvkError::ExpectedPair)
}
}
fn decode_bigint(&self, node: &Self::Node) -> Result<BigInt, FromClvkError> {
if let SExp::Atom = self.sexp(*node) {
Ok(self.number(*node))
} else {
Err(FromClvkError::ExpectedAtom)
}
}
}
impl FromClvk<Allocator> for NodePtr {
fn from_clvk(_decoder: &Allocator, node: NodePtr) -> Result<Self, FromClvkError> {
Ok(node)
}
}