add get() support to nodes (#68)

Author: doxav

opto/trace/nodes.py

@@ -2211,6 +2211,11 @@ def keys(self):
 
         return ops.keys(self)
 
+    def get(self, key, default=None):
+        import opto.trace.operators as ops
+
+        return ops.get(self, node(key), node(default))
+
     def pop(self, __index=-1):
         # python does hidden type checks
         import opto.trace.operators as ops

opto/trace/operators.py

@@ -430,6 +430,14 @@ def values(x: Dict):
     return [k for k in x.values()]
 
 
+@bundle()
+def get(x: Any, key: Any, default: Any = None):
+    """Return the value for key if key is in x, else default."""
+    if not hasattr(x, "get"):
+        raise AttributeError(f"{type(x)} object has no attribute 'get'.")
+    return x.get(key, default)
+
+
 # dict in-place operators