Clean up the scope struct to lookup in the parent as well

src/compiler.rs

@@ -64,7 +64,7 @@ pub struct Compiler<'ctx> {
     // /// is `abc.xyz` in this case and the otherone would be
     // /// `/path/to/abc/xyz.srn` file that contains the ns.
     pub namespaces: HashMap<&'ctx str, Namespace<'ctx>>,
-    // pub fpm: &'a PassManager<FunctionValue<'ctx>>,
+    //pub fpm: &'a PassManager<FunctionValue<'ctx>>,
 
     // current_ns_name: Option<&'a str>,
 }

src/namespace.rs

@@ -14,7 +14,7 @@
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
-use crate::scope::Scope;
+//use crate::scope::Scope;
 use inkwell::context::Context;
 use inkwell::module::Module;
 use inkwell::values::FunctionValue;
@@ -24,28 +24,29 @@ pub struct Namespace<'ctx> {
     /// think of modules as compilation units. Object files if you prefer.
     /// This way we should be able to hot swap the namespaces.
     pub module: Module<'ctx>,
-    scope: Scope<'ctx>,
-    // // The option of the current function being compiled
-    // current_fn_opt: Option<FunctionValue<'ctx>>,
+    //scope: Scope<'ctx>,
+
+    // The option of the current function being compiled
+    current_fn_opt: Option<FunctionValue<'ctx>>,
 }
 
 impl<'ctx> Namespace<'ctx> {
     pub fn new(context: &'ctx Context, name: &str) -> Namespace<'ctx> {
         Namespace {
             module: context.create_module(&name),
-            scope: Scope::new(None),
-            // current_fn_opt: None,
+            //scope: Scope::new(None),
+            current_fn_opt: None,
         }
     }
-    // /// Gets a defined function given its name.
-    // #[inline]
-    // pub fn get_function(&self, name: &str) -> Option<FunctionValue<'ctx>> {
-    //     self.module.get_function(name)
-    // }
+    /// Get a defined function given its name.
+    #[inline]
+    pub fn get_function(&self, name: &str) -> Option<FunctionValue<'ctx>> {
+        self.module.get_function(name)
+    }
 
-    // /// Returns the `FunctionValue` representing the function being compiled.
-    // #[inline]
-    // pub fn current_fn(&self) -> FunctionValue<'ctx> {
-    //     self.current_fn_opt.unwrap()
-    // }
+    /// Return the `FunctionValue` representing the function being compiled.
+    #[inline]
+    pub fn current_fn(&self) -> FunctionValue<'ctx> {
+        self.current_fn_opt.unwrap()
+    }
 }

src/scope.rs

@@ -17,6 +17,9 @@
 use inkwell::values::PointerValue;
 use std::collections::HashMap;
 
+/// Scopes in **Serene** are simply represented by hashmaps. Each
+/// Scope optionally has a parent scope that lookups fallback to
+/// if the lookup key is missing from the current scope.
 pub struct Scope<'a> {
     parent: Option<Box<Scope<'a>>>,
     symbol_table: HashMap<String, PointerValue<'a>>,
@@ -35,8 +38,18 @@ impl<'a> Scope<'a> {
         }
     }
 
+    /// Lookup the given `key` in the scope and if it is not in the current
+    /// scope look it up in the `parent` scope.
     pub fn lookup(&self, key: &str) -> Option<PointerValue> {
-        self.symbol_table.get(key).map(|x| *x)
+        let v = self.symbol_table.get(key);
+
+        if let None = v {
+            return match &self.parent {
+                Some(x) => x.lookup(key),
+                None => None,
+            };
+        }
+        v.map(|x| *x)
     }
 
     pub fn insert(&mut self, key: &str, val: PointerValue<'a>) {