Add spawnu interface for unicode

2 files changed, 26 insertions, 1 deletions

diff --git a/doc/api/pexpect.rst b/doc/api/pexpect.rst
index 7c5ca47..bc24003 100644
--- a/doc/api/pexpect.rst
+++ b/doc/api/pexpect.rst
@@ -34,6 +34,12 @@ spawn object
       communication, data read from the child process, or data sent to the child
       process.
 
+      .. note::
+
+         With a :class:`spawn` instance, the log files should be open for
+         writing binary data. With a :class:`spawnu` instance, they should
+         be open for writing unicode text.
+
 Controlling the child process
 `````````````````````````````
 
@@ -58,6 +64,25 @@ Controlling the child process
 
       The file descriptor used to communicate with the child process.
 
+Handling unicode
+````````````````
+
+For backwards compatibility, :class:`spawn` can handle some Unicode: its
+send methods will encode arbitrary unicode as UTF-8 before sending it to the
+child process, and its expect methods can accept ascii-only unicode strings.
+However, for a proper unicode API to a subprocess, use this subclass:
+
+.. autoclass:: spawnu
+   :show-inheritance:
+
+.. note::
+
+   Unicode handling with pexpect works the same way on Python 2 and 3, despite
+   the difference in names. I.e.:
+
+   - :class:`spawn` works with ``str`` on Python 2, and :class:`bytes` on Python 3,
+   - :class:`spawnu` works with ``unicode`` on Python 2, and :class:`str` on Python 3.
+
 run function
 ------------
 
diff --git a/doc/conf.py b/doc/conf.py
index 84c5ab2..4c82213 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -243,4 +243,4 @@ texinfo_documents = [
 
 
 # Example configuration for intersphinx: refer to the Python standard library.
-intersphinx_mapping = {'http://docs.python.org/': None}
+intersphinx_mapping = {'http://docs.python.org/3/': None}