Move BoundedSeparated helper functions into ast

src/ast/basic.rs

@@ -106,6 +106,40 @@ impl<E> BoundedSeparated<E> {
             .push((Space::empty(self.span), elem, Space::empty(self.span)));
         self
     }
+
+    pub fn map<E2>(self, f: impl Fn(E) -> E2) -> BoundedSeparated<E2> {
+        let elems = self
+            .elems
+            .into_iter()
+            .map(|(s0, e, s1)| (s0, f(e), s1))
+            .collect::<Vec<_>>();
+
+        BoundedSeparated {
+            elems,
+            trailing: self.trailing,
+            span: self.span,
+        }
+    }
+
+    pub fn remove_map<E1, E2>(
+        self,
+        f: impl Fn(E) -> Result<E1, E2>,
+    ) -> (BoundedSeparated<E1>, Vec<(Space, E2, Space)>) {
+        let mut kept = vec![];
+        let mut removed = vec![];
+        for (s0, elem, s1) in self.elems {
+            match f(elem) {
+                Ok(elem) => kept.push((s0, elem, s1)),
+                Err(elem) => removed.push((s0, elem, s1)),
+            }
+        }
+        let new = BoundedSeparated {
+            elems: kept,
+            trailing: self.trailing,
+            span: self.span,
+        };
+        (new, removed)
+    }
 }
 
 impl BoundedSeparated<TableLitElem> {