span: Break out into its own crate, to make room for future expansion

cl-structures/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "cl-structures"
+repository.workspace = true
+version.workspace = true
+authors.workspace = true
+edition.workspace = true
+license.workspace = true
+publish.workspace = true
+
+[dependencies]

cl-structures/src/lib.rs

@@ -0,0 +1,44 @@
+//! # Universally useful structures
+//! - [Span](struct@span::Span): Stores a start and end [Loc](struct@span::Loc)
+//! - [Loc](struct@span::Loc): Stores the index in a stream
+
+pub mod span {
+    //! - [struct@Span]: Stores the start and end [struct@Loc] of a notable AST node
+    //! - [struct@Loc]: Stores the line/column of a notable AST node
+    #![allow(non_snake_case)]
+
+    /// Stores the start and end [locations](struct@Loc) within the token stream
+    #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+    pub struct Span {
+        pub head: Loc,
+        pub tail: Loc,
+    }
+    pub fn Span(head: Loc, tail: Loc) -> Span {
+        Span { head, tail }
+    }
+
+    /// Stores a read-only (line, column) location in a token stream
+    #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+    pub struct Loc {
+        line: u32,
+        col: u32,
+    }
+    pub fn Loc(line: u32, col: u32) -> Loc {
+        Loc { line, col }
+    }
+    impl Loc {
+        pub fn line(self) -> u32 {
+            self.line
+        }
+        pub fn col(self) -> u32 {
+            self.col
+        }
+    }
+
+    impl std::fmt::Display for Loc {
+        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+            let Loc { line, col } = self;
+            write!(f, "{line}:{col}:")
+        }
+    }
+}