Compiler exceptions

Src/AST/Myc.Ast.Scope.pas

@@ -11,9 +11,6 @@ uses
     Myc.Ast.Types;
 
 type
-    // Exception specific to scope resolution and definition errors
-    EScopeException = class(Exception);
-
     IExecutionScope = interface;
     IScopeDescriptor = interface;
     IScopeLayout = interface;
@@ -359,8 +356,8 @@ end;
 function TScopeBuilder.Define(const Name: string): Integer;
 begin
     // Rule: Shadowing / Redefinition in the same scope is forbidden.
-    if FMap.ContainsKey(Name) then
-        raise EScopeException.CreateFmt('Variable "%s" is already defined in this scope.', [Name]);
+    // The Client (Binder) must ensure this name is not already taken before calling Define.
+    Assert(not FMap.ContainsKey(Name), 'Scope Error: Variable "' + Name + '" is already defined in this scope builder.');
 
     // Allocate a new slot
     Result := FNextSlot;
@@ -574,6 +571,8 @@ var
     targetScope: TExecutionScope;
     i: Integer;
 begin
+    Assert(Address.Kind <> akUnresolved, 'Scope Error: Cannot capture an unresolved address.');
+
     case Address.Kind of
         akUpvalue:
         begin
@@ -600,8 +599,6 @@ begin
                 TMonitor.Exit(targetScope);
             end;
         end;
-    else
-        raise EScopeException.Create('Cannot capture an unresolved address.');
     end;
 end;
 
@@ -613,10 +610,9 @@ begin
     NeedNameToIndex;
     id := GetNameID(Name);
 
-    // NOTE: Runtime redefinition is generally restricted in this dynamic Define
-    // (typically used for Root/Global definitions).
-    if FNameToIndex.ContainsKey(id) then
-        raise EScopeException.CreateFmt('Variable "%s" is already defined in this scope.', [Name]);
+    // NOTE: Runtime redefinition is generally restricted in this dynamic Define.
+    // The Client must ensure uniqueness.
+    Assert(not FNameToIndex.ContainsKey(id), 'Scope Error: Variable "' + Name + '" is already defined in this execution scope.');
 
     index := Length(FValues);
     SetLength(FValues, index + 1);
@@ -719,6 +715,8 @@ function TExecutionScope.GetValues(const Address: TResolvedAddress): TDataValue;
 var
     item: TScopeItem;
 begin
+    Assert(Address.Kind <> akUnresolved, 'Scope Error: Cannot get value for an unresolved address.');
+
     case Address.Kind of
         akUpvalue:
         begin
@@ -736,8 +734,6 @@ begin
             else
                 Result := item.Value;
         end;
-    else
-        raise EScopeException.Create('Cannot get value for an unresolved address.');
     end;
 end;
 
@@ -795,6 +791,8 @@ var
     targetScope: TExecutionScope;
     i: Integer;
 begin
+    Assert(Address.Kind <> akUnresolved, 'Scope Error: Cannot set value for an unresolved address.');
+
     case Address.Kind of
         akUpvalue:
         begin
@@ -812,8 +810,6 @@ begin
             else
                 pItem.Value := Value;
         end;
-    else
-        raise EScopeException.Create('Cannot set value for an unresolved address.');
     end;
 end;