From 01611702ec04fa70445fd2c7d37b9b312d3f7561 Mon Sep 17 00:00:00 2001 From: William S Fulton Date: Sat, 19 Dec 2015 03:52:33 +0000 Subject: Python 2 Unicode strings can be used as inputs to char * or std::string types Requires SWIG_PYTHON_2_UNICODE to be defined when compiling generated code. --- Doc/Manual/Contents.html | 1 + Doc/Manual/Python.html | 66 ++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 67 insertions(+) (limited to 'Doc') diff --git a/Doc/Manual/Contents.html b/Doc/Manual/Contents.html index 21ba6eaad..6d2cdaa76 100644 --- a/Doc/Manual/Contents.html +++ b/Doc/Manual/Contents.html @@ -1598,6 +1598,7 @@
  • Buffer interface
  • Abstract base classes
  • Byte string output conversion +
  • Python 2 Unicode diff --git a/Doc/Manual/Python.html b/Doc/Manual/Python.html index 962ee6843..c5219b693 100644 --- a/Doc/Manual/Python.html +++ b/Doc/Manual/Python.html @@ -122,6 +122,7 @@
  • Buffer interface
  • Abstract base classes
  • Byte string output conversion +
  • Python 2 Unicode @@ -6163,6 +6164,71 @@ For more details about the surrogateescape error handler, please see PEP 383.

    +

    36.12.5 Python 2 Unicode

    + + +

    +A Python 3 string is a Unicode string so by default a Python 3 string that contains Unicode +characters passed to C/C++ will be accepted and converted to a C/C++ string +(char * or std::string types). +A Python 2 string is not a unicode string by default and should a Unicode string be +passed to C/C++ it will fail to convert to a C/C++ string +(char * or std::string types). +The Python 2 behavior can be made more like Python 3 by defining +SWIG_PYTHON_2_UNICODE when compiling the generated C/C++ code. +By default when the following is wrapped: +

    + +
    +%module unicode_strings
+char *charstring(char *s) {
+  return s;
+}
+
    + +

    +An error will occur when using Unicode strings in Python 2: +

    + +
    +>>> from unicode_strings import *
+>>> charstring("hi")
+'hi'
+>>> charstring(u"hi")
+Traceback (most recent call last):
+  File "<stdin>", line 1, in ?
+TypeError: in method 'charstring', argument 1 of type 'char *'
+
    + +

    +When the SWIG_PYTHON_2_UNICODE macro is added to the generated code: +

    + +
    +%module unicode_strings
+%begin %{
+#define SWIG_PYTHON_2_UNICODE
+%}
+
+char *charstring(char *s) {
+  return s;
+}
+
    + +

    +Unicode strings will be successfully accepted and converted from UTF-8, +but note that they are returned as a normal Python 2 string: +

    + +
    +>>> from unicode_strings import *
+>>> charstring("hi")
+'hi'
+>>> charstring(u"hi")
+'hi'
+>>>
+
    + -- cgit v1.2.1