bpo-33216: Improve the documentation for CALL_FUNCTION_* (GH-8338) (GH-8784)

Doc/library/dis.rst

@@ -1104,18 +1104,20 @@ All of the following opcodes use their arguments.
 
 .. opcode:: RAISE_VARARGS (argc)
 
-   Raises an exception. *argc* indicates the number of parameters to the raise
+   Raises an exception. *argc* indicates the number of arguments to the raise
    statement, ranging from 0 to 3.  The handler will find the traceback as TOS2,
    the parameter as TOS1, and the exception as TOS.
 
 
 .. opcode:: CALL_FUNCTION (argc)
 
-   Calls a function.  *argc* indicates the number of positional arguments.
-   The positional arguments are on the stack, with the right-most argument
-   on top.  Below the arguments, the function object to call is on the stack.
-   Pops all function arguments, and the function itself off the stack, and
-   pushes the return value.
+   Calls a callable object with positional arguments.
+   *argc* indicates the number of positional arguments.
+   The top of the stack contains positional arguments, with the right-most
+   argument on top.  Below the arguments is a callable object to call.
+   ``CALL_FUNCTION`` pops all arguments and the callable object off the stack,
+   calls the callable object with those arguments, and pushes the return value
+   returned by the callable object.
 
    .. versionchanged:: 3.6
       This opcode is used only for calls with positional arguments.
@@ -1123,31 +1125,36 @@ All of the following opcodes use their arguments.
 
 .. opcode:: CALL_FUNCTION_KW (argc)
 
-   Calls a function.  *argc* indicates the number of arguments (positional
-   and keyword).  The top element on the stack contains a tuple of keyword
-   argument names.  Below the tuple, keyword arguments are on the stack, in
-   the order corresponding to the tuple.  Below the keyword arguments, the
-   positional arguments are on the stack, with the right-most parameter on
-   top.  Below the arguments, the function object to call is on the stack.
-   Pops all function arguments, and the function itself off the stack, and
-   pushes the return value.
+   Calls a callable object with positional (if any) and keyword arguments.
+   *argc* indicates the total number of positional and keyword arguments.
+   The top element on the stack contains a tuple of keyword argument names.
+   Below that are keyword arguments in the order corresponding to the tuple.
+   Below that are positional arguments, with the right-most parameter on
+   top.  Below the arguments is a callable object to call.
+   ``CALL_FUNCTION_KW`` pops all arguments and the callable object off the stack,
+   calls the callable object with those arguments, and pushes the return value
+   returned by the callable object.
 
    .. versionchanged:: 3.6
       Keyword arguments are packed in a tuple instead of a dictionary,
-      *argc* indicates the total number of arguments
+      *argc* indicates the total number of arguments.
 
 
 .. opcode:: CALL_FUNCTION_EX (flags)
 
-   Calls a function. The lowest bit of *flags* indicates whether the
-   var-keyword argument is placed at the top of the stack.  Below the
-   var-keyword argument, the var-positional argument is on the stack.
-   Below the arguments, the function object to call is placed.
-   Pops all function arguments, and the function itself off the stack, and
-   pushes the return value. Note that this opcode pops at most three items
-   from the stack. Var-positional and var-keyword arguments are packed
-   by :opcode:`BUILD_TUPLE_UNPACK_WITH_CALL` and
-   :opcode:`BUILD_MAP_UNPACK_WITH_CALL`.
+   Calls a callable object with variable set of positional and keyword
+   arguments.  If the lowest bit of *flags* is set, the top of the stack
+   contains a mapping object containing additional keyword arguments.
+   Below that is an iterable object containing positional arguments and
+   a callable object to call.  :opcode:`BUILD_MAP_UNPACK_WITH_CALL` and
+   :opcode:`BUILD_TUPLE_UNPACK_WITH_CALL` can be used for merging multiple
+   mapping objects and iterables containing arguments.
+   Before the callable is called, the mapping object and iterable object
+   are each "unpacked" and their contents passed in as keyword and
+   positional arguments respectively.
+   ``CALL_FUNCTION_EX`` pops all arguments and the callable object off the stack,
+   calls the callable object with those arguments, and pushes the return value
+   returned by the callable object.
 
    .. versionadded:: 3.6
 
@@ -1179,7 +1186,8 @@ All of the following opcodes use their arguments.
    Pushes a new function object on the stack.  From bottom to top, the consumed
    stack must consist of values if the argument carries a specified flag value
 
-   * ``0x01`` a tuple of default argument objects in positional order
+   * ``0x01`` a tuple of default values for positional-only and
+     positional-or-keyword parameters in positional order
    * ``0x02`` a dictionary of keyword-only parameters' default values
    * ``0x04`` an annotation dictionary
    * ``0x08`` a tuple containing cells for free variables, making a closure
@@ -1262,7 +1270,7 @@ instructions:
 
 .. data:: hasconst
 
-   Sequence of bytecodes that have a constant parameter.
+   Sequence of bytecodes that access a constant.
 
 
 .. data:: hasfree