3 files changed, 24 insertions, 9 deletions

diff --git a/crates/libsyntax2/src/algo/mod.rs b/crates/libsyntax2/src/algo/mod.rs
index 6efdff12f..2640d60ea 100644
--- a/crates/libsyntax2/src/algo/mod.rs
+++ b/crates/libsyntax2/src/algo/mod.rs
@@ -1,7 +1,10 @@
 pub mod walk;
 pub mod visit;
 
-use {SyntaxNodeRef, TextUnit, TextRange};
+use {
+    SyntaxNodeRef, TextUnit, TextRange,
+    text_utils::{contains_offset_nonstrict, is_subrange},
+};
 
 pub fn find_leaf_at_offset(node: SyntaxNodeRef, offset: TextUnit) -> LeafAtOffset {
     let range = node.range();
@@ -116,14 +119,6 @@ fn common_ancestor<'a>(n1: SyntaxNodeRef<'a>, n2: SyntaxNodeRef<'a>) -> SyntaxNo
     panic!("Can't find common ancestor of {:?} and {:?}", n1, n2)
 }
 
-fn contains_offset_nonstrict(range: TextRange, offset: TextUnit) -> bool {
-    range.start() <= offset && offset <= range.end()
-}
-
-fn is_subrange(range: TextRange, subrange: TextRange) -> bool {
-    range.start() <= subrange.start() && subrange.end() <= range.end()
-}
-
 fn generate<T>(seed: Option<T>, step: impl Fn(&T) -> Option<T>) -> impl Iterator<Item=T> {
     ::itertools::unfold(seed, move |slot| {
         slot.take().map(|curr| {
diff --git a/crates/libsyntax2/src/lib.rs b/crates/libsyntax2/src/lib.rs
index c078baa3a..53ae18988 100644
--- a/crates/libsyntax2/src/lib.rs
+++ b/crates/libsyntax2/src/lib.rs
@@ -39,6 +39,7 @@ mod syntax_kinds;
 mod yellow;
 /// Utilities for simple uses of the parser.
 pub mod utils;
+pub mod text_utils;
 
 pub use {
     text_unit::{TextRange, TextUnit},
diff --git a/crates/libsyntax2/src/text_utils.rs b/crates/libsyntax2/src/text_utils.rs
new file mode 100644
index 000000000..e3d73888f
--- /dev/null
+++ b/crates/libsyntax2/src/text_utils.rs
@@ -0,0 +1,19 @@
+use {TextRange, TextUnit};
+
+pub fn contains_offset_nonstrict(range: TextRange, offset: TextUnit) -> bool {
+    range.start() <= offset && offset <= range.end()
+}
+
+pub fn is_subrange(range: TextRange, subrange: TextRange) -> bool {
+    range.start() <= subrange.start() && subrange.end() <= range.end()
+}
+
+pub fn intersect(r1: TextRange, r2: TextRange) -> Option<TextRange> {
+    let start = r1.start().max(r2.start());
+    let end = r1.end().min(r2.end());
+    if start <= end {
+        Some(TextRange::from_to(start, end))
+    } else {
+        None
+    }
+}