Modifying Functions

modify-argument

Function modifications consist of a list of modify-argument nodes contained in modify-function, add-function or declare-function nodes. Use the remove-argument, replace-default-expression, remove-default-expression, replace-type, reference-count and define-ownership nodes to specify the details of the modification.

<modify-function>
    <modify-argument index="return | this | 1 ..." rename="..."
     invalidate-after-use = "true | false" pyi-type="...">
        // modifications
    </modify-argument>
</modify-function>

Set the index attribute to “1” for the first argument, “2” for the second one and so on. Alternatively, set it to “return” or “this” if you want to modify the function’s return value or the object the function is called upon, respectively.

The optional rename attribute is used to rename a argument and use this new name in the generated code. This attribute can be used to enable the usage of keyword arguments.

The optional pyi-type attribute specifies the type to appear in the signature strings and .pyi files. The type string is determined by checking this attribute value, the replace-type modification and the C++ type. The attribute can be used for example to enclose a pointer return value within Optional[] to indicate that None can occur.

For the optional invalidate-after-use attribute, see Invalidation after use .