libproc_macro: Add Span type rust interface

Add the rust stable interface for Span type in libproc_macro.

ChangeLog:

	* librust/proc_macro/rust/lib.rs: Add span type interface

Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>

1 files changed, 45 insertions, 0 deletions

diff --git a/librust/proc_macro/rust/lib.rs b/librust/proc_macro/rust/lib.rs
index b2da8bb..d3ef527 100644
--- a/librust/proc_macro/rust/lib.rs
+++ b/librust/proc_macro/rust/lib.rs
@@ -1,3 +1,5 @@
+use std::fmt;
+
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub enum Delimiter {
     Parenthesis,
@@ -6,3 +8,46 @@ pub enum Delimiter {
     /// Invisible delimiter
     None,
 }
+
+#[derive(Copy, Clone)]
+pub struct Span {
+    // Internal implementation details
+}
+
+impl Span {
+    // TODO: Add experimental API functions for this type
+
+    /// Creates a new span that resolves at the macro call location
+    pub fn call_site() -> Self {
+        todo!("Implement this function")
+    }
+
+    /// Creates a new span that resolved sometimes at macro call site, and
+    /// sometimes at macro definition site
+    pub fn mixed_site() -> Self {
+        todo!("Implement this function")
+    }
+
+    /// Creates a new span with the same line/column informations but that
+    /// resolve symbols as though it were at `other`
+    pub fn resolved_at(&self, other: Span) -> Self {
+        todo!("Implement this function")
+    }
+
+    /// Creates a new span with the same name resolution behavior as self, but
+    /// with the line/column information of `other`.
+    pub fn located_at(&self, other: Span) -> Self {
+        todo!("Implement this function")
+    }
+
+    /// Return the source text behind a span.
+    pub fn source_text(&self) -> Option<String> {
+        todo!("Implement this function")
+    }
+}
+
+impl fmt::Debug for Span {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        todo!("Implement this function")
+    }
+}