a prototype of an item derivation forest

It seems to be complete now, but still awaits more tests to see where
the errors are, which should be plenty, haha.

1 files changed, 14 insertions, 12 deletions

diff --git a/chain/src/lib.rs b/chain/src/lib.rs
index a3d420b..916678f 100644
--- a/chain/src/lib.rs
+++ b/chain/src/lib.rs
@@ -10,9 +10,16 @@
 
 pub mod atom;
 
-use graph::{error::Error as GError, LabelExtGraph, Parent};
+pub mod item;
 
-use forest::Error as ForestError;
+// TODO: We need a module for items, that serve the role of the
+// forests now.
+
+use graph::{error::Error as GError, LabelExtGraph};
+
+use item::default::Error as ForestError;
+
+use item::PaSe;
 
 /// An edge in the Chain-Rule machine.
 #[derive(Debug, Copy, Clone, Ord, PartialOrd, Eq, PartialEq, Hash)]
@@ -20,14 +27,14 @@ pub struct Edge {
     /// The position in the atomic languages.
     label: usize,
     /// The source of the associated forest edge.
-    forest_source: Parent,
+    forest_source: PaSe,
     /// Whether or not this edge is "accepting".
     accepting: bool,
 }
 
 impl Edge {
     /// Construct a new edge.
-    pub fn new(label: usize, forest_source: Parent, accepting: bool) -> Self {
+    pub fn new(label: usize, forest_source: PaSe, accepting: bool) -> Self {
         Self {
             label,
             forest_source,
@@ -46,7 +53,7 @@ impl Edge {
     }
 
     /// Return the associated forest edge of the edge.
-    pub fn forest_source(&self) -> Parent {
+    pub fn forest_source(&self) -> PaSe {
         self.forest_source
     }
 }
@@ -56,12 +63,7 @@ impl core::fmt::Display for Edge {
         let label = self.label();
         let forest_source = self.forest_source();
 
-        write!(
-            f,
-            "edge label {label} with forest source {} and edge index {}",
-            forest_source.node(),
-            forest_source.edge()
-        )
+        write!(f, "edge label {label} with item {}", forest_source)
     }
 }
 
@@ -84,7 +86,7 @@ pub enum TwoLayers {
     /// the source of the associated forest edge of the second layer,
     /// and the third is a list of edges, which are the common first
     /// layers.
-    Two(usize, Parent, bool, Vec<(Edge, usize)>),
+    Two(usize, PaSe, bool, Vec<(Edge, usize)>),
 }
 
 /// The type of a collapsed iterator.