Support namespaces when resolving symbols

A definition can resolve a reference in the same or a deeper namespace,
allowing for proper scoping and shadowing. Multiple definitions in the
same namespace cannot share a name.

1 files changed, 23 insertions, 0 deletions

diff --git a/src/source_unit.rs b/src/source_unit.rs
index 7ee6993..bc6d4ab 100644
--- a/src/source_unit.rs
+++ b/src/source_unit.rs
@@ -115,6 +115,29 @@ pub struct Symbol {
     pub role: SymbolRole,
 }
 
+impl Symbol {
+    /// True if this symbol is a valid definition for a reference symbol
+    pub fn defines(&self, reference: &Symbol) -> bool {
+        self.name == reference.name &&
+        std::iter::zip(&self.namespace, &reference.namespace).all(|(a, b)| a == b)
+    }
+}
+
+impl PartialEq for Symbol {
+    fn eq(&self, other: &Symbol) -> bool {
+        self.name == other.name && self.namespace == other.namespace
+    }
+}
+
+impl std::fmt::Debug for Symbol {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
+        for name in &self.namespace {
+            write!(f, "{name}:")?
+        }
+        write!(f, "{}", self.name)
+    }
+}
+
 #[derive(Copy, Clone, Debug, PartialEq)]
 pub enum SymbolRole {
     Definition(DefinitionType),