Finally figured out how I want atoms to work

orchid-extension/src/expr.rs

@@ -0,0 +1,53 @@
+use orchid_api::atom::Atom;
+use orchid_api::expr::ExprTicket;
+use orchid_api::system::SysId;
+use orchid_base::id_store::IdStore;
+use orchid_base::intern::Token;
+
+use crate::atom::{encode_atom_nodrop, DynOwnedAtom, OwnedAtom, ThinAtom, OBJ_STORE};
+use crate::system::DynSystem;
+
+pub enum GenClause {
+  Call(Box<GenClause>, Box<GenClause>),
+  Lambda(Token<String>, Box<GenClause>),
+  Arg(Token<String>),
+  Slot(ExprTicket),
+  Seq(Box<GenClause>, Box<GenClause>),
+  Const(Token<Vec<Token<String>>>),
+  ThinAtom(Box<dyn Fn(SysId, &dyn DynSystem) -> Atom>),
+  OwnedAtom(u64),
+}
+
+pub fn cnst(path: Token<Vec<Token<String>>>) -> GenClause { GenClause::Const(path) }
+pub fn val<A: ThinAtom>(atom: A) -> GenClause {
+  GenClause::ThinAtom(Box::new(move |id, sys| encode_atom_nodrop::<A>(id, sys.card(), &atom)))
+}
+
+pub fn obj<A: OwnedAtom>(atom: A) -> GenClause {
+  GenClause::OwnedAtom(OBJ_STORE.add(Box::new(atom)))
+}
+
+pub fn seq(ops: impl IntoIterator<Item = GenClause>) -> GenClause {
+  fn recur(mut ops: impl Iterator<Item = GenClause>) -> Option<GenClause> {
+    let op = ops.next()?;
+    Some(match recur(ops) {
+      None => op,
+      Some(rec) => GenClause::Seq(Box::new(op), Box::new(rec)),
+    })
+  }
+  recur(ops.into_iter()).expect("Empty list provided to seq!")
+}
+
+pub fn slot(extk: ExprTicket) -> GenClause { GenClause::Slot(extk) }
+
+pub fn arg(n: Token<String>) -> GenClause { GenClause::Arg(n) }
+
+pub fn lambda(n: Token<String>, b: impl IntoIterator<Item = GenClause>) -> GenClause {
+  GenClause::Lambda(n, Box::new(call(b)))
+}
+
+pub fn call(v: impl IntoIterator<Item = GenClause>) -> GenClause {
+  v.into_iter()
+    .reduce(|f, x| GenClause::Call(Box::new(f), Box::new(x)))
+    .expect("Empty call expression")
+}