Add parameter names and missing specialization to the 'function' builtin

Author: otethal

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/BuiltinConstructors.java

@@ -2007,7 +2007,8 @@ PZip zip(VirtualFrame frame, Object cls, Object[] args,
     }
 
     // function(code, globals[, name[, argdefs[, closure]]])
-    @Builtin(name = "function", minNumOfPositionalArgs = 3, maxNumOfPositionalArgs = 6, constructsClass = PythonBuiltinClassType.PFunction, isPublic = false)
+    @Builtin(name = "function", minNumOfPositionalArgs = 3, parameterNames = {"$cls", "code", "globals", "name", "argdefs",
+                    "closure"}, constructsClass = PythonBuiltinClassType.PFunction, isPublic = false)
     @GenerateNodeFactory
     public abstract static class FunctionNode extends PythonBuiltinNode {
         private static final TruffleString T_LAMBDA = tsLiteral("<lambda>");
@@ -2038,6 +2039,14 @@ public PFunction function(@SuppressWarnings("unused") Object cls, PCode code, PD
             return factory().createFunction(name, code, globals, PCell.toCellArray(getObjectArrayNode.execute(closure)));
         }
 
+        @Specialization
+        public PFunction function(@SuppressWarnings("unused") Object cls, PCode code, PDict globals, @SuppressWarnings("unused") PNone name, PTuple defaultArgs,
+                        @SuppressWarnings("unused") PNone closure,
+                        @Shared("getObjectArrayNode") @Cached GetObjectArrayNode getObjectArrayNode) {
+            // TODO split defaults of positional args from kwDefaults
+            return factory().createFunction(code.getName(), code, globals, getObjectArrayNode.execute(defaultArgs), null, null);
+        }
+
         @Specialization
         public PFunction function(@SuppressWarnings("unused") Object cls, PCode code, PDict globals, TruffleString name, PTuple defaultArgs, @SuppressWarnings("unused") PNone closure,
                         @Shared("getObjectArrayNode") @Cached GetObjectArrayNode getObjectArrayNode) {