From 9fd80ff6d18fd0a9435c7252e22b59aa0075f6ca Mon Sep 17 00:00:00 2001
From: Mario Carneiro <di.gama@gmail.com>
Date: Sat, 30 Sep 2023 01:43:20 -0400
Subject: [PATCH] add const_ranges iterator

---
 src/scopeck.rs | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/scopeck.rs b/src/scopeck.rs
index d236c92..24d77b1 100644
--- a/src/scopeck.rs
+++ b/src/scopeck.rs
@@ -124,6 +124,16 @@ pub struct VerifyExpr {
     pub tail: Box<[ExprFragment]>,
 }
 
+impl VerifyExpr {
+    /// Returns an iterator over runs of constants in the expression,
+    /// as references into the constant pool.
+    pub fn const_ranges(&self) -> impl Iterator<Item = Range<usize>> + '_ {
+        (self.tail.iter().map(|e| &e.prefix))
+            .chain(std::iter::once(&self.rump))
+            .cloned()
+    }
+}
+
 /// Representation of a hypothesis in a frame program.
 #[derive(Clone, Debug)]
 pub enum Hyp {