Fix tuple constant access

typon/include/python/builtins.hpp

@@ -406,4 +406,14 @@ auto call_sync(auto f) {
   }
 }
 
+namespace typon {
+template <auto IDX, typename T> auto constant_get(T &&val) {
+  if constexpr (requires { std::get<IDX>(std::forward<T>(val)); }) {
+    return std::get<IDX>(std::forward<T>(val));
+  } else {
+    return dot(std::forward<T>(val), oo__getitem__oo)(IDX);
+  }
+}
+}; // namespace typon
+
 #endif // TYPON_BUILTINS_HPP

typon/trans/transpiler/phases/emit_cpp/expr.py

@@ -336,14 +336,16 @@ class ExpressionVisitor(NodeVisitor):
         if isinstance(node.type, ClassTypeType):
             yield from self.visit_BaseType(node.type.inner_type)
             return
-        if isinstance(node.value.type, TupleInstanceType):
-            if not (isinstance(node.slice, ast.Constant) and isinstance(node.slice.value, int)):
-                raise NotImplementedError("Tuple subscript with non-constant not handled yet")
-            yield "std::get<"
+
+        if isinstance(node.slice, ast.Constant) and isinstance(node.slice.value, int):
+            # when the index is a constant, we special case the emitted code so we can use std::get
+            # if the subscripted object is a tuple because tuples are not subscriptable in C++ because
+            # the language is statically typed
+            yield "(co_await typon::constant_get<"
             yield str(node.slice.value)
             yield ">("
             yield from self.visit(node.value)
-            yield ")"
+            yield "))"
             return
         # yield "("
         # yield from self.visit(node.value)