New example

git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk/SWIG@775 626c5289-ae23-0410-ae9c-e8d60b6d4f22

7 files changed, 407 insertions, 0 deletions

diff --git a/Examples/python/class/Makefile b/Examples/python/class/Makefile
new file mode 100644
index 000000000..71af176f9
--- /dev/null
+++ b/Examples/python/class/Makefile
@@ -0,0 +1,19 @@
+TOP        = ../..
+SWIG       = $(TOP)/../swig
+CXXSRCS    = example.cxx
+TARGET     = example
+INTERFACE  = example.i
+LIBS       = -lm
+
+all::
+	$(MAKE) -f $(TOP)/Makefile CXXSRCS='$(CXXSRCS)' SWIG='$(SWIG)' \
+	TARGET='$(TARGET)' INTERFACE='$(INTERFACE)' python_cpp
+
+static::
+	$(MAKE) -f $(TOP)/Makefile CXXSRCS='$(CXXSRCS)' SWIG='$(SWIG)' \
+	TARGET='mypython' INTERFACE='$(INTERFACE)' python_cpp_static
+
+clean::
+	rm -f *_wrap* *.o *~ *.so mypython *.pyc .~* core
+
+check: all
diff --git a/Examples/python/class/example.cxx b/Examples/python/class/example.cxx
new file mode 100644
index 000000000..21582f4d1
--- /dev/null
+++ b/Examples/python/class/example.cxx
@@ -0,0 +1,28 @@
+/* File : example.c */
+
+#include "example.h"
+#include <math.h>
+
+/* Move the shape to a new location */
+void Shape::move(double dx, double dy) {
+  x += dx;
+  y += dy;
+}
+
+int Shape::nshapes = 0;
+
+double Circle::area() {
+  return M_PI*radius*radius;
+}
+
+double Circle::perimeter() {
+  return 2*M_PI*radius;
+}
+
+double Square::area() {
+  return width*width;
+}
+
+double Square::perimeter() {
+  return 4*width;
+}
diff --git a/Examples/python/class/example.h b/Examples/python/class/example.h
new file mode 100644
index 000000000..849071dd3
--- /dev/null
+++ b/Examples/python/class/example.h
@@ -0,0 +1,39 @@
+/* File : example.h */
+
+class Shape {
+public:
+  Shape() {
+    nshapes++;
+  }
+  virtual ~Shape() {
+    nshapes--;
+  };
+  double  x, y;   
+  void    move(double dx, double dy);
+  virtual double area() = 0;
+  virtual double perimeter() = 0;
+  static  int nshapes;
+};
+
+class Circle : public Shape {
+private:
+  double radius;
+public:
+  Circle(double r) : radius(r) { };
+  virtual double area();
+  virtual double perimeter();
+};
+
+class Square : public Shape {
+private:
+  double width;
+public:
+  Square(double w) : width(w) { };
+  virtual double area();
+  virtual double perimeter();
+};
+
+
+
+
+  
diff --git a/Examples/python/class/example.i b/Examples/python/class/example.i
new file mode 100644
index 000000000..23ee8a822
--- /dev/null
+++ b/Examples/python/class/example.i
@@ -0,0 +1,11 @@
+/* File : example.i */
+%module example
+
+%{
+#include "example.h"
+%}
+
+/* Let's just grab the original header file here */
+
+%include "example.h"
+
diff --git a/Examples/python/class/example.py b/Examples/python/class/example.py
new file mode 100644
index 000000000..0e578da7b
--- /dev/null
+++ b/Examples/python/class/example.py
@@ -0,0 +1,70 @@
+# file: example.py
+
+# This file illustrates the low-level C++ interface
+# created by SWIG.  In this case, all of our C++ classes
+# get converted into function calls.
+
+import example 
+
+# ----- Object creation -----
+
+print "Creating some objects:"
+c = example.new_Circle(10)
+print "    Created circle", c
+s = example.new_Square(10)
+print "    Created square", s
+
+# ----- Access a static member -----
+
+print "\nA total of", example.cvar.Shape_nshapes,"shapes were created"
+
+# ----- Member data access -----
+
+# Set the location of the object
+
+# Notice how we can do this using functions specific to
+# the 'Circle' class.
+example.Circle_x_set(c, 20)
+example.Circle_y_set(c, 30)
+
+# Now use the same functions in the base class
+example.Shape_x_set(s,-10)
+example.Shape_y_set(s,5)
+
+print "\nHere is their current position:"
+print "    Circle = (%f, %f)" % (example.Shape_x_get(c), example.Shape_y_get(c))
+print "    Square = (%f, %f)" % (example.Shape_x_get(s), example.Shape_y_get(s))
+
+# ----- Call some methods -----
+
+print "\nHere are some properties of the shapes:"
+for o in [c,s]:
+      print "   ", o
+      print "        area      = ", example.Shape_area(o)
+      print "        perimeter = ", example.Shape_perimeter(o)
+
+# Notice how the Shape_area() and Shape_perimeter() functions really
+# invoke the appropriate virtual method on each object.
+
+# ----- Try to cause a type error -----
+
+print "\nI'm going to try and break the type system"
+try:
+    # Bad script!
+    Square_area(c)         # Try to invoke Square method on a Circle
+    print "    Bad bad SWIG!"
+except:
+    print "    Well, it didn't work. Good SWIG."
+
+
+# ----- Delete everything -----
+
+print "\nGuess I'll clean up now"
+
+# Note: this invokes the virtual destructor
+example.delete_Shape(c)
+example.delete_Shape(s)
+
+print example.cvar.Shape_nshapes,"shapes remain"
+print "Goodbye"
+
diff --git a/Examples/python/class/index.html b/Examples/python/class/index.html
new file mode 100644
index 000000000..3529b3ca9
--- /dev/null
+++ b/Examples/python/class/index.html
@@ -0,0 +1,239 @@
+<html>
+<head>
+<title>SWIG:Examples:python:class</title>
+</head>
+
+<body bgcolor="#ffffff">
+
+
+<tt>SWIG/Examples/python/class/</tt>
+<hr>
+
+<H2>Wrapping a simple C++ class</H2>
+
+<tt>$Header$</tt><br>
+
+<p>
+This example illustrates the most primitive form of C++ class wrapping performed
+by SWIG.  In this case, C++ classes are simply transformed into a collection of
+C-style functions that provide access to class members.
+
+<h2>The C++ Code</h2>
+
+Suppose you have some C++ classes described by the following (and admittedly lame) 
+header file:
+
+<blockquote>
+<pre>
+/* File : example.h */
+
+class Shape {
+public:
+  Shape() {
+    nshapes++;
+  }
+  virtual ~Shape() {
+    nshapes--;
+  };
+  double  x, y;   
+  void    move(double dx, double dy);
+  virtual double area() = 0;
+  virtual double perimeter() = 0;
+  static  int nshapes;
+};
+
+class Circle : public Shape {
+private:
+  double radius;
+public:
+  Circle(double r) : radius(r) { };
+  virtual double area();
+  virtual double perimeter();
+};
+
+class Square : public Shape {
+private:
+  double width;
+public:
+  Square(double w) : width(w) { };
+  virtual double area();
+  virtual double perimeter();
+};
+</pre>
+</blockquote>
+
+<h2>The SWIG interface</h2>
+
+A simple SWIG interface for this can be built by simply grabbing the header file
+like this:
+
+<blockquote>
+<pre>
+/* File : example.i */
+%module example
+
+%{
+#include "example.h"
+%}
+
+/* Let's just grab the original header file here */
+%include "example.h"
+</pre>
+</blockquote>
+
+Note: when creating a C++ extension, you must run SWIG with the <tt>-c++</tt> option like this:
+<blockquote>
+<pre>
+% swig -c++ -python example.i
+</pre>
+</blockquote>
+
+<h2>A sample Python script</h2>
+
+Click <a href="example.py">here</a> to see a script that calls the C++ functions from Python.
+
+<h2>Key points</h2>
+
+<ul>
+<li>To create a new object, you call a constructor like this:
+
+<blockquote>
+<pre>
+c = example.new_Circle(10.0)
+</pre>
+</blockquote>
+
+<p>
+<li>To access member data, a pair of accessor functions are used.
+For example:
+
+<blockquote>
+<pre>
+example.Circle_x_set(c,15)    # Set member data
+x = example.Shape_x_get(c)    # Get member data
+</pre>
+</blockquote>
+
+Note: when accessing member data, the name of the base class or the derived class can be
+used in the function name as shown above.  Of course, it would probably be more
+proper to just use the base class version such as <tt>Shape_x_get()</tt>
+
+<p>
+<li>To invoke a member function, you simply do this
+
+<blockquote>
+<pre>
+print "The area is ", example.Shape_area(c)
+</pre>
+</blockquote>
+
+<p>
+<li>Type checking knows about the inheritance structure of C++. For example:
+
+<blockquote>
+<pre>
+example.Shape_area(c)       # Works (c is a Shape)
+example.Circle_area(c)      # Works (c is a Circle)
+example.Square_area(c)      # Fails (c is definitely not a Square)
+</pre>
+</blockquote>
+
+<p>
+<li>To invoke a destructor, simply do this
+
+<blockquote>
+<pre>
+example.delete_Shape(c)     # Deletes a shape
+</pre>
+</blockquote>
+
+(Note: destructors are currently not inherited. This might change later).
+
+<p>
+<li>Static member variables are wrapped as C global variables.  For example:
+
+<blockquote>
+<pre>
+n = example.cvar.Shape_nshapes     # Get a static data member
+example.cvar.Shapes_nshapes = 13   # Set a static data member
+</pre>
+</blockquote>
+
+</ul>
+
+<h2>General Comments</h2>
+
+<ul>
+<li>This low-level interface is not the only way to handle C++ code.  Shadow classes
+provide a much higher-level interface.
+
+<p>
+<li>SWIG *does* know how to properly perform upcasting of objects in an inheritance
+hierarchy (including multiple inheritance).  Therefore it is perfectly safe to pass
+an object of a derived class to any function involving a base class.
+
+<p>
+<li>A wide variety of C++ features are not currently supported by SWIG.  Here is the
+short and incomplete list:
+
+<p>
+<ul>
+<li>Overloaded methods and functions.  SWIG wrappers don't know how to resolve name
+conflicts so you must give an alternative name to any overloaded method name using the
+%name directive like this:
+
+<blockquote>
+<pre>
+void foo(int a);  
+%name(foo2) void foo(double a, double b);
+</pre>
+</blockquote>
+
+<p>
+<li>Overloaded operators.  Not supported at all. The only workaround for this is
+to write a helper function. For example:
+
+<blockquote>
+<pre>
+%inline %{
+    Vector *vector_add(Vector *a, Vector *b) {
+          ... whatever ...
+    }
+%}
+</pre>
+</blockquote>
+
+<p>
+<li>Namespaces.  Not supported at all. Won't be supported until SWIG2.0 (if at all).
+
+<p>
+<li>Templates.  Not supported at all. SWIG throws out anything that looks like a template.
+You can work around the problem by aliasing a template class behind a typedef however. 
+For example:
+
+<blockquote>
+<pre>
+%{
+typedef vector<int> IntVector;
+%}
+
+class IntVector {
+public:
+    ... methods ...
+};
+</pre>
+</blockquote>
+</ul>
+<p>
+<li>There is no guarantee that an extremely complex C++ application will be able to compile
+as a Python extension.  Sorry.
+
+<p>
+<li>Dave's snide remark: Like a large bottle of strong Tequilla, it's better to
+use C++	in moderation.
+
+</ul>
+
+<hr>
+</body>
+</html>
diff --git a/Examples/python/index.html b/Examples/python/index.html
index 802db9b75..68b0bdfa1 100644
--- a/Examples/python/index.html
+++ b/Examples/python/index.html
@@ -18,6 +18,7 @@ be used to wrap a C function, a global variable, and a constant.
 certain C declarations are turned into constants.
 <li><a href="variables/index.html">variables</a>. An example showing how to access C global variables from Python.
 <li><a href="value/index.html">value</a>. How to pass and return structures by value.
+<li><a href="class/index.html">class</a>. Wrapping a simple C++ class.
 </ul>
 
 <h2>Compilation Issues</h2>