From 0e4f4c5af67b4075174ace5a1c7800dae60a9d11 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Mon, 11 Nov 2019 10:52:57 +0000
Subject: Move Span definition to its own file

And prepare for more variants
---
 dhall_syntax/src/core/span.rs | 44 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 dhall_syntax/src/core/span.rs

(limited to 'dhall_syntax/src/core/span.rs')

diff --git a/dhall_syntax/src/core/span.rs b/dhall_syntax/src/core/span.rs
new file mode 100644
index 0000000..ad5a3a9
--- /dev/null
+++ b/dhall_syntax/src/core/span.rs
@@ -0,0 +1,44 @@
+use std::rc::Rc;
+
+/// A location in the source text
+#[derive(Debug, Clone)]
+pub struct ParsedSpan {
+    input: Rc<str>,
+    /// # Safety
+    ///
+    /// Must be a valid character boundary index into `input`.
+    start: usize,
+    /// # Safety
+    ///
+    /// Must be a valid character boundary index into `input`.
+    end: usize,
+}
+
+/// A location in the source text
+#[derive(Debug, Clone)]
+pub enum Span {
+    Parsed(ParsedSpan),
+}
+
+impl Span {
+    pub(crate) fn make(input: Rc<str>, sp: pest::Span) -> Self {
+        Span::Parsed(ParsedSpan {
+            input,
+            start: sp.start(),
+            end: sp.end(),
+        })
+    }
+    /// Takes the union of the two spans. Assumes that the spans come from the same input.
+    /// This will also capture any input between the spans.
+    pub fn union(&self, other: &Span) -> Self {
+        use std::cmp::{max, min};
+        use Span::*;
+        match (self, other) {
+            (Parsed(x), Parsed(y)) => Span::Parsed(ParsedSpan {
+                input: x.input.clone(),
+                start: min(x.start, y.start),
+                end: max(x.start, y.start),
+            }),
+        }
+    }
+}
-- 
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