SWIG Parameter Handling

David M. Beazley

dave-swig@dabeaz.com

January 9, 2007

Introduction

This document describes the functions related to management of function parameters and parameter lists in the SWIG core. These functions are declared in Source/Swig/swigparm.h. This API is considered to be stable.

Parameters

The following utility functions are used to create and copy individual parameters. In their most basic form, a parameter merely contains a type, a name, and an optional default value.

``Parm *NewParm(SwigType *type, const String_or_char *name)``

Creates a new parameter object with type type and name name. The type is stored in the attribute “type” and the name is stored in the attribute “name”.

``Parm *CopyParm(Parm *p)``

Copies a parameter object. All string attributes are copied in the process of making the copy. However, no complex attributes (lists, hashes, etc.) are copied.

Parameter Lists

``ParmList *CopyParmList(ParmList *p)``

Creates a copy of a parameter list. A parameter list is merely a linked list of parameters created by NewParm().

``ParmList *CopyParmListMax(ParmList *p, int count)``

Copies at most count parameters from the parameter list p.

``int ParmList_len(ParmList *p)``

Returns the total number of parameters in a parameter list.

``int ParmList_numrequired(ParmList *p)``

Returns the number of required parameters in a parameter list. This pertains to invoking a function/method in C/C++.

``int ParmList_has_defaultargs(ParmList *p)``

Returns 1 if the parameter list has any default arguments. Otherwise returns 0.

Code Generation Functions

``String *ParmList_str(ParmList *p)``

Creates a C prototype string of the parameters, but without any default values.

``String *ParmList_str_defaultargs(ParmList *p)``

Creates a C prototype string of the parameters and includes the default values (if any).

``String *ParmList_protostr(ParmList *p)``

Creates a C prototype string of the parameters.