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-rw-r--r--chain/src/lib.rs38
1 files changed, 32 insertions, 6 deletions
diff --git a/chain/src/lib.rs b/chain/src/lib.rs
index a7740c2..d7fc519 100644
--- a/chain/src/lib.rs
+++ b/chain/src/lib.rs
@@ -16,7 +16,7 @@ use graph::{error::Error as GError, LabelExtGraph};
use item::default::Error as ForestError;
-use item::PaSe;
+use item::PaVi;
/// An edge in the Chain-Rule machine.
#[derive(Debug, Copy, Clone, Ord, PartialOrd, Eq, PartialEq, Hash)]
@@ -24,18 +24,25 @@ pub struct Edge {
/// The position in the atomic languages.
label: usize,
/// The source of the associated forest edge.
- forest_source: PaSe,
+ forest_source: PaVi,
+ /// The bottom source on which we shall perform reduction.
+ ///
+ /// If this equals `forest_source`, no extra reduction needs to be
+ /// done.
+ true_source: PaVi,
/// Whether or not this edge is "accepting".
accepting: bool,
}
impl Edge {
/// Construct a new edge.
- pub fn new(label: usize, forest_source: PaSe, accepting: bool) -> Self {
+ pub fn new(label: usize, forest_source: PaVi, accepting: bool) -> Self {
+ let true_source = forest_source;
Self {
label,
forest_source,
accepting,
+ true_source,
}
}
@@ -50,9 +57,21 @@ impl Edge {
}
/// Return the associated forest edge of the edge.
- pub fn forest_source(&self) -> PaSe {
+ pub fn forest_source(&self) -> PaVi {
self.forest_source
}
+
+ /// Return the associated bottom edge of the edge from which
+ /// onwards we shall perform the reduction.
+ pub fn set_true_source(&mut self, true_source: PaVi) {
+ self.true_source = true_source;
+ }
+
+ /// Return the associated bottom edge of the edge from which
+ /// onwards we shall perform the reduction.
+ pub fn true_source(&self) -> PaVi {
+ self.true_source
+ }
}
impl core::fmt::Display for Edge {
@@ -137,7 +156,7 @@ 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, PaSe, bool, Vec<(Roi, usize)>),
+ Two(usize, PaVi, bool, Vec<(Roi, usize)>),
}
/// The type of a collapsed iterator.
@@ -239,12 +258,15 @@ pub trait Chain: LabelExtGraph<Edge> {
/// An iterator that iterates all layers that need to be merged.
type DerIter: Iterator<Item = TwoLayers>;
+ // FIXME: Add a parameter to control whether to manipulate the
+ // forests or not.
+
/// Take the derivative by a terminal `t` at position `pos`.
fn derive(&mut self, t: usize, pos: usize) -> Result<Self::DerIter, Self::Error>;
/// Take the union of all derivatives.
fn union(&mut self, der_iter: Self::DerIter) -> Result<Vec<(Roi, usize)>, Self::Error> {
- // REVIEW: Find a way to avoid allocations.
+ // REVIEW: Think about the possibilities to avoid allocations.
Collapsed::<_, Self>::collapse(der_iter, self)
.collect::<Result<Vec<(Roi, usize)>, Self::Error>>()
.map(|mut v| {
@@ -276,6 +298,10 @@ pub trait Chain: LabelExtGraph<Edge> {
Ok(())
}
+
+ /// Signal to the parser that the end of the input is reached, so
+ /// that the parser knows to generate suitable forests.
+ fn end_of_input(&mut self) -> Result<(), Self::Error>;
}
pub mod default;