Implement iterator for context.

src/context/global_settings.rs

@@ -0,0 +1,16 @@
+#[derive(Debug)]
+pub struct GlobalSettings<'s> {
+    placeholder: Option<&'s str>,
+}
+
+impl<'s> GlobalSettings<'s> {
+    pub fn new() -> Self {
+        GlobalSettings { placeholder: None }
+    }
+}
+
+impl<'s> Default for GlobalSettings<'s> {
+    fn default() -> Self {
+        GlobalSettings::new()
+    }
+}

src/context/list.rs

@@ -27,6 +27,10 @@ impl<'parent, T> List<'parent, T> {
     pub fn iter(&self) -> Iter<'_, T> {
         Iter { next: Some(self) }
     }
+
+    pub fn iter_list(&self) -> IterList<'_, T> {
+        Iter { next: Some(self) }
+    }
 }
 
 pub trait ListType<'parent, T> {
@@ -64,3 +68,17 @@ impl<'a, T> Iterator for Iter<'a, T> {
         ret
     }
 }
+
+pub struct IterList<'a, T> {
+    next: Link<'a, T>,
+}
+
+impl<'a, T> Iterator for IterList<'a, T> {
+    type Item = &'a List<'a, T>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let ret = self.next;
+        self.next = self.next.map(|this| this.get_parent()).flatten();
+        ret
+    }
+}

src/context/mod.rs

@@ -3,6 +3,7 @@ use crate::error::Res;
 use crate::parser::OrgSource;
 
 mod exiting;
+mod global_settings;
 mod list;
 mod parser_context;
 mod parser_with_context;

src/context/parser_context.rs

@@ -1,6 +1,7 @@
 use nom::combinator::eof;
 
 use super::exiting::ExitClass;
+use super::global_settings::GlobalSettings;
 use super::list::List;
 use super::DynContextMatcher;
 use crate::error::Res;
@@ -128,33 +129,16 @@ impl<'r> std::fmt::Debug for ExitMatcherNode<'r> {
     }
 }
 
-#[derive(Debug)]
-pub struct GlobalSettings<'s> {
-    placeholder: Option<&'s str>,
-}
-
-impl<'s> GlobalSettings<'s> {
-    pub fn new() -> Self {
-        GlobalSettings { placeholder: None }
-    }
-}
-
-impl<'s> Default for GlobalSettings<'s> {
-    fn default() -> Self {
-        GlobalSettings::new()
-    }
-}
-
 #[derive(Debug)]
 pub struct Context<'r, 's> {
     global_settings: &'s GlobalSettings<'s>,
-    tree: List<'r, ContextElement<'r, 's>>,
+    tree: &'r List<'r, ContextElement<'r, 's>>,
 }
 
 impl<'r, 's> Context<'r, 's> {
     pub fn new(
         global_settings: &'s GlobalSettings<'s>,
-        tree: List<'r, ContextElement<'r, 's>>,
+        tree: &'r List<'r, ContextElement<'r, 's>>,
     ) -> Self {
         Self {
             global_settings,
@@ -162,16 +146,6 @@ impl<'r, 's> Context<'r, 's> {
         }
     }
 
-    pub fn document_context(global_settings: &'s GlobalSettings<'s>) -> Self {
-        Context::new(
-            global_settings,
-            List::new(ContextElement::ExitMatcherNode(ExitMatcherNode {
-                exit_matcher: &document_end,
-                class: ExitClass::Document,
-            })),
-        )
-    }
-
     pub fn with_additional_node(&self, data: ContextElement<'r, 's>) -> Self {
         let new_tree = self.tree.push(data);
         Self {
@@ -179,6 +153,24 @@ impl<'r, 's> Context<'r, 's> {
             tree: new_tree,
         }
     }
+
+    pub fn iter(&self) -> super::list::Iter<'r, ContextElement<'r, 's>> {
+        self.tree.iter()
+    }
+
+    pub fn iter_context(&self) -> Iter<'r, 's> {
+        Iter {
+            next: self.tree.iter_list(),
+            global_settings: self.global_settings,
+        }
+    }
+
+    pub fn get_parent(&self) -> Option<Self> {
+        self.tree.get_parent().map(|parent_tree| Self {
+            global_settings: self.global_settings,
+            tree: parent_tree,
+        })
+    }
 }
 
 #[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
@@ -188,3 +180,27 @@ fn document_end<'r, 's>(
 ) -> Res<OrgSource<'s>, OrgSource<'s>> {
     eof(input)
 }
+
+pub struct Iter<'r, 's> {
+    global_settings: &'s GlobalSettings<'s>,
+    next: super::list::IterList<'r, ContextElement<'r, 's>>,
+}
+
+impl<'r, 's> Iterator for Iter<'r, 's> {
+    type Item = Context<'r, 's>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let next_tree = self.next.next();
+        let ret = next_tree.map(|parent_tree| Context::new(self.global_settings, parent_tree));
+        ret
+    }
+}
+
+impl<'r, 's> ContextElement<'r, 's> {
+    pub fn document_context() -> Self {
+        Self::ExitMatcherNode(ExitMatcherNode {
+            exit_matcher: &document_end,
+            class: ExitClass::Document,
+        })
+    }
+}