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Add support for the Go programming language.

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git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk@12108 626c5289-ae23-0410-ae9c-e8d60b6d4f22
This commit is contained in:
Ian Lance Taylor 2010-06-10 01:13:31 +00:00
commit 5af2978f77
259 changed files with 16159 additions and 14 deletions
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18
Examples/go/pointer/Makefile Normal file
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TOP = ../..
SWIG = $(TOP)/../preinst-swig
SRCS = example.c
TARGET = example
INTERFACE = example.i
SWIGOPT =
all:: go
go::
$(MAKE) -f $(TOP)/Makefile SRCS='$(SRCS)' SWIG='$(SWIG)' \
SWIGOPT='$(SWIGOPT)' TARGET='$(TARGET)' INTERFACE='$(INTERFACE)' go
clean::
$(MAKE) -f $(TOP)/Makefile go_clean
check: all
$(MAKE) -f $(TOP)/Makefile TARGET='$(TARGET)' INTERFACE='$(INTERFACE)' go_run

16
Examples/go/pointer/example.c Normal file
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/* File : example.c */
void add(int *x, int *y, int *result) {
*result = *x + *y;
}
void sub(int *x, int *y, int *result) {
*result = *x - *y;
}
int divide(int n, int d, int *r) {
int q;
q = n/d;
*r = n - q*d;
return q;
}

68
Examples/go/pointer/example.go Normal file
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/* ----------------------------------------------------------------------------
* This file was automatically generated by SWIG (http://www.swig.org).
* Version 2.0.1
*
* This file is not intended to be easily readable and contains a number of
* coding conventions designed to improve portability and efficiency. Do not make
* changes to this file unless you know what you are doing--modify the SWIG
* interface file instead.
* ----------------------------------------------------------------------------- */
package example
type _swig_fnptr *byte
type _swig_memberptr *byte
func _swig_allocatememory(int) *byte
func _swig_internal_allocate(len int) *byte {
return _swig_allocatememory(len)
}
func _swig_allocatestring(*byte, int) string
func _swig_internal_makegostring(p *byte, l int) string {
return _swig_allocatestring(p, l)
}
func _swig_internal_gopanic(p *byte, l int) {
panic(_swig_allocatestring(p, l))
}
func _swig_wrap_add(*int, *int, *int)
func Add(arg1 *int, arg2 *int, arg3 *int) {
_swig_wrap_add(arg1, arg2, arg3)
}
func New_intp() *int
func Copy_intp(int) *int
func _swig_wrap_delete_intp(*int)
func Delete_intp(arg1 *int) {
_swig_wrap_delete_intp(arg1)
}
func _swig_wrap_intp_assign(*int, int)
func Intp_assign(arg1 *int, arg2 int) {
_swig_wrap_intp_assign(arg1, arg2)
}
func Intp_value(*int) int
func _swig_wrap_sub(int, int, []int)
func Sub(arg1 int, arg2 int, arg3 []int) {
_swig_wrap_sub(arg1, arg2, arg3)
}
func Divide(int, int, []int) int
type SwigcptrVoid uintptr
type Void interface {
Swigcptr() uintptr;
}
func (p SwigcptrVoid) Swigcptr() uintptr {
return uintptr(p)
}

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Examples/go/pointer/example.i Normal file
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/* File : example.i */
%module example
%{
extern void add(int *, int *, int *);
extern void sub(int *, int *, int *);
extern int divide(int, int, int *);
%}
/* This example illustrates a couple of different techniques
for manipulating C pointers */
/* First we'll use the pointer library */
extern void add(int *x, int *y, int *result);
%include cpointer.i
%pointer_functions(int, intp);
/* Next we'll use some typemaps */
%include typemaps.i
extern void sub(int *INPUT, int *INPUT, int *OUTPUT);
/* Next we'll use typemaps and the %apply directive */
%apply int *OUTPUT { int *r };
extern int divide(int n, int d, int *r);

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Examples/go/pointer/index.html Normal file
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<html>
<head>
<title>SWIG:Examples:go:pointer</title>
</head>
<body bgcolor="#ffffff">
<tt>SWIG/Examples/go/pointer/</tt>
<hr>
<H2>Simple Pointer Handling</H2>
<p>
This example illustrates a couple of techniques for handling simple
pointers in SWIG. The prototypical example is a C function that
operates on pointers such as this:
<blockquote>
<pre>
void add(int *x, int *y, int *r) {
*r = *x + *y;
}
</pre>
</blockquote>
By default, SWIG wraps this function exactly as specified and creates
an interface that expects pointer objects for arguments. This only
works when there is a precise correspondence between the C type and
some Go type.
<p>
<h2>Other approaches</h2>
<p>
<li>The SWIG pointer library provides a different, safer, way to
handle pointers. For example, in the interface file you would do
this:
<blockquote>
<pre>
%include cpointer.i
%pointer_functions(int, intp);
</pre>
</blockquote>
and from Go you would use pointers like this:
<blockquote>
<pre>
a := example.New_intp()
b := example.New_intp()
c := example.New_intp()
Intp_Assign(a, 37)
Intp_Assign(b, 42)
fmt.Println(" a =", a)
fmt.Println(" b =", b)
fmt.Println(" c =", c)
// Call the add() function with some pointers
example.Add(a,b,c)
// Now get the result
res := example.Intp_value(c)
fmt.Println(" 37 + 42 =", res)
// Clean up the pointers
example.Delete_intp(a)
example.Delete_intp(b)
example.Delete_intp(c)
</pre>
</blockquote>
<p>
<li>Use the SWIG typemap library. This library allows you to
completely change the way arguments are processed by SWIG. For
example:
<blockquote>
<pre>
%include "typemaps.i"
void add(int *INPUT, int *INPUT, int *OUTPUT);
</pre>
</blockquote>
And in a Go program:
<blockquote>
<pre>
r := []int{0}
example.Sub(37,42,r)
fmt.Println("Result =", r[0])
</pre>
</blockquote>
Needless to say, this is substantially easier although a bit unusual.
<p>
<li>A final alternative is to use the typemaps library in combination
with the %apply directive. This allows you to change the names of parameters
that behave as input or output parameters. For example:
<blockquote>
<pre>
%include "typemaps.i"
%apply int *INPUT {int *x, int *y};
%apply int *OUTPUT {int *r};
void add(int *x, int *y, int *r);
void sub(int *x, int *y, int *r);
void mul(int *x, int *y, int *r);
... etc ...
</pre>
</blockquote>
</ul>
<h2>Example</h2>
The following example illustrates the use of these features for pointer
extraction.
<ul>
<li> <a href="example.c">example.c</a> (C Source)
<li> <a href="example.i">example.i</a> (SWIG interface)
<li> <a href="runme.go">runme.go</a> (Go program)
</ul>
<h2>Notes</h2>
<ul>
<li>Since pointers are used for so many different things (arrays, output values,
etc...) the complexity of pointer handling can be as complicated as you want to
make it.
<p>
<li>More documentation on the typemaps.i and cpointer.i library files can be
found in the SWIG user manual. The files also contain documentation.
</ul>
<hr>
</body>
</html>

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package main
import (
"fmt"
. "./example"
)
func main() {
// First create some objects using the pointer library.
fmt.Println("Testing the pointer library")
a := New_intp()
b := New_intp()
c := New_intp()
Intp_assign(a, 37)
Intp_assign(b, 42)
fmt.Println(" a =", a)
fmt.Println(" b =", b)
fmt.Println(" c =", c)
// Call the add() function with some pointers
Add(a, b, c)
// Now get the result
res := Intp_value(c)
fmt.Println(" 37 + 42 =", res)
// Clean up the pointers
Delete_intp(a)
Delete_intp(b)
Delete_intp(c)
// Now try the typemap library
// Now it is no longer necessary to manufacture pointers.
// Instead we use a single element array which in Java is modifiable.
fmt.Println("Trying the typemap library")
r := []int{0}
Sub(37, 42, r)
fmt.Println(" 37 - 42 = ", r[0])
// Now try the version with return value
fmt.Println("Testing return value")
q := Divide(42, 37, r)
fmt.Println(" 42/37 = ", q, " remainder ", r[0])
}