Add nu-protocol

crates/nu-protocol/src/span.rs

@@ -0,0 +1,37 @@
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct Span {
+    pub start: usize,
+    pub end: usize,
+}
+
+impl Span {
+    pub fn new(start: usize, end: usize) -> Span {
+        Span { start, end }
+    }
+
+    pub fn unknown() -> Span {
+        Span { start: 0, end: 0 }
+    }
+
+    pub fn offset(&self, offset: usize) -> Span {
+        Span {
+            start: self.start - offset,
+            end: self.end - offset,
+        }
+    }
+}
+
+pub fn span(spans: &[Span]) -> Span {
+    let length = spans.len();
+
+    if length == 0 {
+        Span::unknown()
+    } else if length == 1 {
+        spans[0]
+    } else {
+        Span {
+            start: spans[0].start,
+            end: spans[length - 1].end,
+        }
+    }
+}