restore old files now!

src/line.rs

@@ -0,0 +1,43 @@
+use std::num::NonZeroU64;
+
+#[allow(unused_imports)]
+use crate::prelude::*;
+
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct Line(pub u64);
+
+/// Constructors.
+impl Line {
+    pub const fn from_index(index: u64) -> Self {
+        Self(index)
+    }
+
+    pub const fn from_linenr(linenr: NonZeroU64) -> Self {
+        Self(linenr.get() - 1)
+    }
+
+    pub const fn next(self) -> Self {
+        Self::from_index(self.index() + 1)
+    }
+
+    /// Panics if self is line index 0.
+    pub const fn prev(self) -> Self {
+        Self::from_index(self.index() - 1)
+    }
+}
+
+/// Getters.
+impl Line {
+    /// 0-indexed
+    pub const fn index(self) -> u64 {
+        self.0
+    }
+
+    /// 1-indexed
+    pub const fn linenr(self) -> u64 {
+        self.0 + 1
+    }
+}
+
+pub struct Lines(Vec<Line>);