diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..d75311a
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,3 @@
+mod pos;
+
+pub use pos::*;
diff --git a/src/pos.rs b/src/pos.rs
new file mode 100644
index 0000000..632385e
--- /dev/null
+++ b/src/pos.rs
@@ -0,0 +1,55 @@
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub struct LinePos {
+    index: usize,
+    lineno: usize,
+}
+
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub struct CharPos {
+    line: LinePos,
+    col: usize,
+}
+
+impl LinePos {
+    pub fn new(index: usize, lineno: usize) -> Self {
+        assert!(lineno >= 1);
+        Self { index, lineno }
+    }
+
+    pub fn index(&self) -> usize {
+        self.index
+    }
+
+    pub fn lineno(&self) -> usize {
+        self.lineno
+    }
+}
+
+impl CharPos {
+    pub fn new(line: &LinePos, col: usize) -> Self {
+        assert!(col >= 1);
+        Self { line: *line, col }
+    }
+
+    pub fn line(&self) -> LinePos {
+        self.line
+    }
+
+    pub fn index(&self) -> usize {
+        self.line.index
+    }
+
+    pub fn lineno(&self) -> usize {
+        self.line.lineno
+    }
+
+    pub fn col(&self) -> usize {
+        self.col
+    }
+}
+
+impl From<CharPos> for LinePos {
+    fn from(char_pos: CharPos) -> Self {
+        char_pos.line
+    }
+}