%varargs - better documentation and remove additional argument generation which didn't work properly as a sentinel

git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk@12666 626c5289-ae23-0410-ae9c-e8d60b6d4f22

CHANGES.current

@@ -4,6 +4,14 @@ See the RELEASENOTES file for a summary of changes in each release.
 
 Version 2.0.4 (in progress)
 ===========================
+2011-05-14: wsfulton
+	    %varargs when used with a numeric argument used to create an additional argument 
+            which was intended to provide a guaranteed sentinel value. This never worked and now
+            the additional argument is not generated.
+
+2011-05-13: wsfulton
+	    [python] Additional fixes for python3.2 support.
+
 2011-05-07: szager
 	    [python] Fixed PyGetSetDescr for python3.2.
 

Doc/Manual/Varargs.html

@@ -331,33 +331,62 @@ int open(const char *path, int oflags, int mode = 0);
 <p>
 In this case, <tt>%varargs</tt> is simply providing more specific information about the
 extra arguments that might be passed to a function.  
-If the parameters to a varargs function are of uniform type, <tt>%varargs</tt> can also
+If the arguments to a varargs function are of uniform type, <tt>%varargs</tt> can also
 accept a numerical argument count as follows:
 </p>
 
 <div class="code">
 <pre>
-%varargs(10,char *arg = NULL) execlp;
+%varargs(3, char *str = NULL) execlp;
 ...
-int execlp(const char *path, const char *arg1, ...);
+int execlp(const char *path, const char *arg, ...);
 </pre>
 </div>
 
 <p>
-This would wrap <tt>execlp()</tt> as a function that accepted up to 10 optional arguments.
+and is effectively seen as:
+</p>
+
+<div class="code">
+<pre>
+int execlp(const char *path, const char *arg, 
+           char *str1 = NULL, 
+           char *str2 = NULL, 
+           char *str3 = NULL);
+</pre>
+</div>
+
+<p>
+This would wrap <tt>execlp()</tt> as a function that accepted up to 3 optional arguments.
 Depending on the application, this may be more than enough for practical purposes.
 </p>
 
 <p>
-Argument replacement is most appropriate in cases where the types of
-the extra arguments is uniform and the maximum number of arguments is
-known.  When replicated argument replacement is used, at least one extra
-argument is added to the end of the arguments when making the function call. 
-This argument serves as a sentinel to make sure the list is properly terminated.
-It has the same value as that supplied to the <tt>%varargs</tt> directive.
+The handling of <a href="SWIGPlus.html#SWIGPlus_default_args">default arguments</a> can be changed via the
+<tt>compactdefaultargs</tt> feature. If this feature is used, for example
+</p>
+
+<div class="code">
+<pre>
+%feature("compactdefaultargs") execlp;
+%varargs(3, char *str = NULL) execlp;
+...
+int execlp(const char *path, const char *arg, ...);
+</pre>
+</div>
+
+<p>
+a call from the target language which does not provide the maximum number of arguments, such as,
+<tt>execlp("a", "b", "c")</tt>
+will generate C code which includes the missing default values, that is, <tt>execlp("a", "b", "c", NULL, NULL)</tt>. 
+If <tt>compactdefaultargs</tt> is not used, then the generated code will be
+<tt>execlp("a", "b", "c")</tt>. The former is useful for helping providing a sentinel to terminate the argument list.
 </p>
 
 <p>
+Argument replacement is most appropriate in cases where the types of
+the extra arguments are uniform and the maximum number of arguments are
+known. 
 Argument replacement is not as useful when working with functions that accept
 mixed argument types such as <tt>printf()</tt>.  Providing general purpose
 wrappers to such functions presents special problems (covered shortly).  

Examples/test-suite/python/varargs_runme.py

@@ -27,11 +27,10 @@ if varargs.test_plenty("Hello", 1) != "Hello":
 if varargs.test_plenty("Hello", 1, 2) != "Hello":
     raise RuntimeError, "Failed"
 
-if varargs.test_plenty("Hello", 1, 2, 3) != "Hello":
-    raise RuntimeError, "Failed"
-
 try:
-    varargs.test_plenty("Hello", 1, 2, 3, 4)
+    varargs.test_plenty("Hello", 1, 2, 3)
     raise RuntimeError
 except NotImplementedError:
     pass
+except TypeError:
+    pass

Source/CParse/parser.y

@@ -2627,10 +2627,15 @@ varargs_parms   : parms { $$ = $1; }
 		    Swig_error(cparse_file, cparse_line,"Argument count in %%varargs must be positive.\n");
 		    $$ = 0;
 		  } else {
+		    String *name = Getattr($3, "name");
 		    $$ = Copy($3);
-		    Setattr($$,"name","VARARGS_SENTINEL");
-		    for (i = 0; i < n; i++) {
+		    if (name)
+		      Setattr($$, "name", NewStringf("%s%d", name, n));
+		    for (i = 1; i < n; i++) {
 		      p = Copy($3);
+		      name = Getattr(p, "name");
+		      if (name)
+		        Setattr(p, "name", NewStringf("%s%d", name, n-i));
 		      set_nextSibling(p,$$);
 		      Delete($$);
 		      $$ = p;