From 15b369028fbfcee559d9f4a8e37e2d71428add29 Mon Sep 17 00:00:00 2001
From: Vadim Zeitlin <vz-swig@zeitlins.org>
Date: Sun, 10 Aug 2014 03:56:04 +0200
Subject: [PATCH] Allow using enum elements as default values for Python
 functions.

Enum values are just (integer) constants in Python and so can be used as the
function default values just as well as literal numbers, account for this when
checking whether function parameters can be represented in Python.

Also rename is_primitive_defaultargs() to is_representable_as_pyargs() to
describe better what this function does.
---
 .../test-suite/python/default_args_runme.py   |  3 +
 Source/Modules/python.cxx                     | 63 ++++++++++---------
 2 files changed, 35 insertions(+), 31 deletions(-)

diff --git a/Examples/test-suite/python/default_args_runme.py b/Examples/test-suite/python/default_args_runme.py
index 091a92376..ad5e03d11 100644
--- a/Examples/test-suite/python/default_args_runme.py
+++ b/Examples/test-suite/python/default_args_runme.py
@@ -1,5 +1,8 @@
 import default_args 
 
+ec = default_args.EnumClass()
+if not ec.blah():
+  raise RuntimeError,"EnumClass::blah() default arguments don't work"
 
 if default_args.Statics_staticMethod() != 60:
   raise RuntimeError
diff --git a/Source/Modules/python.cxx b/Source/Modules/python.cxx
index 21ab81a10..389daf69c 100644
--- a/Source/Modules/python.cxx
+++ b/Source/Modules/python.cxx
@@ -1659,14 +1659,8 @@ public:
       // Write default value
       if (value && !calling) {
 	String *new_value = convertValue(value, Getattr(p, "type"));
-	if (new_value) {
-	  value = new_value;
-	} else {
-	  Node *lookup = Swig_symbol_clookup(value, 0);
-	  if (lookup)
-	    value = Getattr(lookup, "sym:name");
-	}
-	Printf(doc, "=%s", value);
+	if (new_value)
+	  Printf(doc, "=%s", new_value);
       }
       Delete(type_str);
       Delete(made_name);
@@ -1817,39 +1811,46 @@ public:
 
   /* ------------------------------------------------------------
    * convertValue()
-   *    Check if string v can be a Python value literal,
-   *    (eg. number or string), or translate it to a Python literal.
+   *    Check if string v can be a Python value literal or a
+   *    constant. Return NIL if it isn't.
    * ------------------------------------------------------------ */
   String *convertValue(String *v, SwigType *t) {
-    if (v && Len(v) > 0) {
-      char fc = (Char(v))[0];
-      if (('0' <= fc && fc <= '9') || '\'' == fc || '"' == fc) {
-	/* number or string (or maybe NULL pointer) */
-	if (SwigType_ispointer(t) && Strcmp(v, "0") == 0)
-	  return NewString("None");
-	else
-	  return v;
-      }
-      if (Strcmp(v, "true") == 0 || Strcmp(v, "TRUE") == 0)
-	return NewString("True");
-      if (Strcmp(v, "false") == 0 || Strcmp(v, "FALSE") == 0)
-	return NewString("False");
-      if (Strcmp(v, "NULL") == 0 || Strcmp(v, "nullptr") == 0)
-	return SwigType_ispointer(t) ? NewString("None") : NewString("0");
+    char fc = (Char(v))[0];
+    if (('0' <= fc && fc <= '9') || '\'' == fc || '"' == fc) {
+      /* number or string (or maybe NULL pointer) */
+      if (SwigType_ispointer(t) && Strcmp(v, "0") == 0)
+	return NewString("None");
+      else
+	return v;
     }
-    return 0;
+    if (Strcmp(v, "true") == 0 || Strcmp(v, "TRUE") == 0)
+      return NewString("True");
+    if (Strcmp(v, "false") == 0 || Strcmp(v, "FALSE") == 0)
+      return NewString("False");
+    if (Strcmp(v, "NULL") == 0 || Strcmp(v, "nullptr") == 0)
+      return SwigType_ispointer(t) ? NewString("None") : NewString("0");
+
+    // This could also be an enum type, default value of which is perfectly
+    // representable in Python.
+    Node *lookup = Swig_symbol_clookup(v, 0);
+    if (lookup) {
+      if (Cmp(Getattr(lookup, "nodeType"), "enumitem") == 0)
+	return Getattr(lookup, "sym:name");
+    }
+
+    return NIL;
   }
+
   /* ------------------------------------------------------------
-   * is_primitive_defaultargs()
+   * is_representable_as_pyargs()
    *    Check if the function parameters default argument values
-   *    have primitive types, so that their default values could be
-   *    used in Python code.
+   *    can be represented in Python.
    *
    *    If this method returns false, the parameters will be translated
    *    to a generic "*args" which allows us to deal with default values
    *    at C++ code level where they can always be handled.
    * ------------------------------------------------------------ */
-  bool is_primitive_defaultargs(Node *n) {
+  bool is_representable_as_pyargs(Node *n) {
     ParmList *plist = CopyParmList(Getattr(n, "parms"));
     Parm *p;
     Parm *pnext;
@@ -1913,7 +1914,7 @@ public:
       n = nn;
 
     /* For overloaded function, just use *args */
-    if (is_real_overloaded(n) || GetFlag(n, "feature:compactdefaultargs") || !is_primitive_defaultargs(n)) {
+    if (is_real_overloaded(n) || GetFlag(n, "feature:compactdefaultargs") || !is_representable_as_pyargs(n)) {
       String *parms = NewString("");
       if (in_class)
 	Printf(parms, "self, ");