break down engine modules

edn/src/edn_item.rs

@@ -55,52 +55,8 @@ impl<T: AsRef<str> + PartialEq + Default + Clone + std::fmt::Debug> EdnItem<T> {
         EdnIterator::new(&self)
     }
 }
-enum EdnIterator<'a, T>{
-    Nil,
-    Sym(&'a T),
-    Exp(Vec<EdnIterator<'a, T>>)
-}
-impl<'a, T: AsRef<str>> EdnIterator<'a, T> {
-    fn new (item: &'a EdnItem<T>) -> Self {
-        use EdnItem::*;
-        match item {
-            Sym(t) => Self::Sym(t),
-            Exp(i) => Self::Exp(i.iter().map(EdnIterator::new).collect()),
-            _ => Self::Nil,
-        }
-    }
-}
-impl<'a, T: AsRef<str>> Iterator for EdnIterator<'a, T> {
-    type Item = &'a T;
-    fn next (&mut self) -> Option<Self::Item> {
-        use EdnIterator::*;
-        match self {
-            Sym(t) => {
-                let t = *t;
-                *self = Nil;
-                Some(t)
-            },
-            Exp(v) => match v.as_mut_slice() {
-                [a] => if let Some(next) = a.next() {
-                    Some(next)
-                } else {
-                    *self = Exp(v.split_off(1));
-                    self.next()
-                },
-                _ => {
-                    *self = Nil;
-                    None
-                }
-            },
-            _ => {
-                *self = Nil;
-                None
-            }
-        }
-    }
-}
 impl EdnItem<String> {
-    fn from (other: EdnItem<impl AsRef<str>>) -> EdnItem<String> {
+    pub fn from (other: EdnItem<impl AsRef<str>>) -> EdnItem<String> {
         use EdnItem::*;
         match other {
             Nil => Nil,