wip: iterator magic

edn/src/token.rs

@@ -161,7 +161,31 @@ pub trait Atom<'a>: Sized {
     Num(usize),
     Sym(&'a str),
     Key(&'a str),
-    Exp(TokenIterator<'a>),
+    Exp(RefAtomIterator<'a>),
+}
+type RefAtomResult<'a> = Result<RefAtom<'a>, ParseError>;
+#[derive(Clone, PartialEq)] pub struct RefAtomIterator<'a>(TokenIterator<'a>);
+impl<'a> Iterator for RefAtomIterator<'a> {
+    type Item = RefAtomResult<'a>;
+    fn next (&mut self) -> Option<RefAtomResult<'a>> {
+        Some(if let Some(result) = Iterator::next(&mut self.0) {
+            match result {
+                Err(e) => Err(e),
+                Ok(token) => match token.kind {
+                    Nil => Err(ParseError::Empty),
+                    Num => match to_number(token.slice_source(self.0.0)) {
+                        Ok(n) => Ok(RefAtom::Num(n)),
+                        Err(e) => Err(e)
+                    },
+                    Sym => Ok(RefAtom::Sym(token.slice_source(self.0.0))),
+                    Key => Ok(RefAtom::Key(token.slice_source(self.0.0))),
+                    Exp => todo!()
+                }
+            }
+        } else {
+            return None
+        })
+    }
 }
 impl<'a> RefAtom<'a> {
     pub fn to_arc_atom (&self) -> ArcAtom {
@@ -195,7 +219,9 @@ impl<'a> Atom<'a> for RefAtom<'a> {
                 },
                 Sym => Ok(RefAtom::Sym(token.slice_source(source))),
                 Key => Ok(RefAtom::Key(token.slice_source(source))),
-                Exp => Ok(RefAtom::Exp(TokenIterator::new(token.slice_source(source))))
+                Exp => Ok(
+                    RefAtom::Exp(RefAtomIterator(TokenIterator::new(token.slice_source(source))))
+                )
             },
         })
     }