Add encoder and decoder proc

Author: WyattBlue

auto_editor/lang/palet.py

@@ -646,8 +646,8 @@ def pop(self) -> None:
 
 
 def my_eval(env: Env, node: object) -> Any:
-    def make_trace(sym: Sym) -> str:
-        return f"  at {sym.val} ({sym.lineno}:{sym.column})"
+    def make_trace(sym: object) -> str:
+        return f"  at {sym.val} ({sym.lineno}:{sym.column})" if type(sym) is Sym else ""
 
     if type(node) is Sym:
         val = env.get(node.val)

auto_editor/lang/stdenv.py

@@ -2,6 +2,8 @@
 
 from typing import TYPE_CHECKING
 
+import av
+
 from auto_editor.analyze import mut_remove_large, mut_remove_small
 from auto_editor.lib.contracts import *
 from auto_editor.lib.data_structs import *
@@ -749,6 +751,13 @@ def attr(env: Env, node: Node) -> Any:
             raise MyError("@r: attribute must be an identifier")
 
         base = my_eval(env, node[1])
+
+        if hasattr(base, "__pyx_vtable__"):
+            try:
+                return getattr(base, node[2].val)
+            except AttributeError as e:
+                raise MyError(e)
+
         if type(base) is PaletClass:
             if type(name := node[2]) is not Sym:
                 raise MyError("@r: class attribute must be an identifier")
@@ -1171,6 +1180,9 @@ def change_file_ext(a, ext) -> str:
             "string->vector", lambda s: [Char(c) for c in s], (1, 1), is_str
         ),
         "range->vector": Proc("range->vector", list, (1, 1), is_range),
+        # av
+        "encoder": Proc("encoder", lambda x: av.Codec(x, "w"), (1, 1), is_str),
+        "decoder": Proc("decoder", lambda x: av.Codec(x), (1, 1), is_str),
         # reflexion
         "var-exists?": Proc("var-exists?", lambda sym: sym.val in env, (1, 1), is_symbol),
         "rename": Syntax(syn_rename),