Improve io.rprint* interface, unify usage in ipkernel.

Starting to use print_function where possible.

IPython/utils/io.py

@@ -1,286 +1,294 b''
 # encoding: utf-8
 """
 IO related utilities.
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2009  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
+from __future__ import print_function
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 import sys
 import tempfile
 
 from IPython.external.Itpl import itpl, printpl
 
 #-----------------------------------------------------------------------------
 # Code
 #-----------------------------------------------------------------------------
 
 
 class IOStream:
 
     def __init__(self,stream,fallback):
         if not hasattr(stream,'write') or not hasattr(stream,'flush'):
             stream = fallback
         self.stream = stream
         self._swrite = stream.write
         self.flush = stream.flush
 
     def write(self,data):
         try:
             self._swrite(data)
         except:
             try:
                 # print handles some unicode issues which may trip a plain
-                # write() call.  Attempt to emulate write() by using a
-                # trailing comma
-                print >> self.stream, data,
+                # write() call.  Emulate write() by using an empty end
+                # argument.
+                print(data, end='', file=self.stream)
             except:
                 # if we get here, something is seriously broken.
-                print >> sys.stderr, \
-                      'ERROR - failed to write data to stream:', self.stream
+                print('ERROR - failed to write data to stream:', self.stream,
+                      file=sys.stderr)
 
     # This class used to have a writeln method, but regular files and streams
     # in Python don't have this method. We need to keep this completely
     # compatible so we removed it.
 
     def close(self):
         pass
 
 
 class IOTerm:
     """ Term holds the file or file-like objects for handling I/O operations.
 
     These are normally just sys.stdin, sys.stdout and sys.stderr but for
     Windows they can can replaced to allow editing the strings before they are
     displayed."""
 
     # In the future, having IPython channel all its I/O operations through
     # this class will make it easier to embed it into other environments which
     # are not a normal terminal (such as a GUI-based shell)
     def __init__(self, cin=None, cout=None, cerr=None):
         self.cin  = IOStream(cin, sys.stdin)
         self.cout = IOStream(cout, sys.stdout)
         self.cerr = IOStream(cerr, sys.stderr)
 
 
 class Tee(object):
     """A class to duplicate an output stream to stdout/err.
 
     This works in a manner very similar to the Unix 'tee' command.
 
     When the object is closed or deleted, it closes the original file given to
     it for duplication.
     """
     # Inspired by:
     # http://mail.python.org/pipermail/python-list/2007-May/442737.html
 
     def __init__(self, file_or_name, mode=None, channel='stdout'):
         """Construct a new Tee object.
 
         Parameters
         ----------
         file_or_name : filename or open filehandle (writable)
           File that will be duplicated
 
         mode : optional, valid mode for open().
           If a filename was give, open with this mode.
 
         channel : str, one of ['stdout', 'stderr']  
         """
         if channel not in ['stdout', 'stderr']:
             raise ValueError('Invalid channel spec %s' % channel)
         
         if hasattr(file, 'write') and hasattr(file, 'seek'):
             self.file = file_or_name
         else:
             self.file = open(file_or_name, mode)
         self.channel = channel
         self.ostream = getattr(sys, channel)
         setattr(sys, channel, self)
         self._closed = False
 
     def close(self):
         """Close the file and restore the channel."""
         self.flush()
         setattr(sys, self.channel, self.ostream)
         self.file.close()
         self._closed = True
 
     def write(self, data):
         """Write data to both channels."""
         self.file.write(data)
         self.ostream.write(data)
         self.ostream.flush()
 
     def flush(self):
         """Flush both channels."""
         self.file.flush()
         self.ostream.flush()
 
     def __del__(self):
         if not self._closed:
             self.close()
 
 
 def file_read(filename):
     """Read a file and close it.  Returns the file source."""
     fobj = open(filename,'r');
     source = fobj.read();
     fobj.close()
     return source
 
 
 def file_readlines(filename):
     """Read a file and close it.  Returns the file source using readlines()."""
     fobj = open(filename,'r');
     lines = fobj.readlines();
     fobj.close()
     return lines
 
 
 def raw_input_multi(header='', ps1='==> ', ps2='..> ',terminate_str = '.'):
     """Take multiple lines of input.
 
     A list with each line of input as a separate element is returned when a
     termination string is entered (defaults to a single '.'). Input can also
     terminate via EOF (^D in Unix, ^Z-RET in Windows).
 
     Lines of input which end in \\ are joined into single entries (and a
     secondary continuation prompt is issued as long as the user terminates
     lines with \\). This allows entering very long strings which are still
     meant to be treated as single entities.
     """
 
     try:
         if header:
             header += '\n'
         lines = [raw_input(header + ps1)]
     except EOFError:
         return []
     terminate = [terminate_str]
     try:
         while lines[-1:] != terminate:
             new_line = raw_input(ps1)
             while new_line.endswith('\\'):
                 new_line = new_line[:-1] + raw_input(ps2)
             lines.append(new_line)
 
         return lines[:-1]  # don't return the termination command
     except EOFError:
         print
         return lines
 
 
 def raw_input_ext(prompt='',  ps2='... '):
     """Similar to raw_input(), but accepts extended lines if input ends with \\."""
 
     line = raw_input(prompt)
     while line.endswith('\\'):
         line = line[:-1] + raw_input(ps2)
     return line
 
 
 def ask_yes_no(prompt,default=None):
     """Asks a question and returns a boolean (y/n) answer.
 
     If default is given (one of 'y','n'), it is used if the user input is
     empty. Otherwise the question is repeated until an answer is given.
 
     An EOF is treated as the default answer.  If there is no default, an
     exception is raised to prevent infinite loops.
 
     Valid answers are: y/yes/n/no (match is not case sensitive)."""
 
     answers = {'y':True,'n':False,'yes':True,'no':False}
     ans = None
     while ans not in answers.keys():
         try:
             ans = raw_input(prompt+' ').lower()
             if not ans:  # response was an empty string
                 ans = default
         except KeyboardInterrupt:
             pass
         except EOFError:
             if default in answers.keys():
                 ans = default
                 print
             else:
                 raise
 
     return answers[ans]
 
 
 class NLprinter:
     """Print an arbitrarily nested list, indicating index numbers.
 
     An instance of this class called nlprint is available and callable as a
     function.
 
     nlprint(list,indent=' ',sep=': ') -> prints indenting each level by 'indent'
     and using 'sep' to separate the index from the value. """
 
     def __init__(self):
         self.depth = 0
 
     def __call__(self,lst,pos='',**kw):
         """Prints the nested list numbering levels."""
         kw.setdefault('indent',' ')
         kw.setdefault('sep',': ')
         kw.setdefault('start',0)
         kw.setdefault('stop',len(lst))
         # we need to remove start and stop from kw so they don't propagate
         # into a recursive call for a nested list.
         start = kw['start']; del kw['start']
         stop = kw['stop']; del kw['stop']
         if self.depth == 0 and 'header' in kw.keys():
-            print kw['header']
+            print(kw['header'])
 
         for idx in range(start,stop):
             elem = lst[idx]
             if type(elem)==type([]):
                 self.depth += 1
                 self.__call__(elem,itpl('$pos$idx,'),**kw)
                 self.depth -= 1
             else:
                 printpl(kw['indent']*self.depth+'$pos$idx$kw["sep"]$elem')
 
 nlprint = NLprinter()
 
 
 def temp_pyfile(src, ext='.py'):
     """Make a temporary python file, return filename and filehandle.
 
     Parameters
     ----------
     src : string or list of strings (no need for ending newlines if list)
       Source code to be written to the file.
 
     ext : optional, string
       Extension for the generated file.
 
     Returns
     -------
     (filename, open filehandle)
       It is the caller's responsibility to close the open file and unlink it.
     """
     fname = tempfile.mkstemp(ext)[1]
     f = open(fname,'w')
     f.write(src)
     f.flush()
     return fname, f
 
 
-def rprint(*info):
+def rprint(*args, **kw):
+    """Raw print to sys.__stdout__"""
+    
+    print(*args, sep=kw.get('sep', ' '), end=kw.get('end', '\n'),
+          file=sys.__stdout__)
+    sys.__stdout__.flush()
+
+
+def rprinte(*args, **kw):
     """Raw print to sys.__stderr__"""
     
-    for item in info:
-        print >> sys.__stderr__, item,
-    print >> sys.__stderr__
+    print(*args, sep=kw.get('sep', ' '), end=kw.get('end', '\n'),
+          file=sys.__stderr__)
     sys.__stderr__.flush()

IPython/zmq/ipkernel.py

@@ -1,399 +1,400 b''
 #!/usr/bin/env python
 """A simple interactive kernel that talks to a frontend over 0MQ.
 
 Things to do:
 
 * Implement `set_parent` logic. Right before doing exec, the Kernel should
   call set_parent on all the PUB objects with the message about to be executed.
 * Implement random port and security key logic.
 * Implement control messages.
 * Implement event loop and poll version.
 """
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
+from __future__ import print_function
 
 # Standard library imports.
 import __builtin__
 import sys
 import time
 import traceback
 
 # System library imports.
 import zmq
 
 # Local imports.
 from IPython.config.configurable import Configurable
+from IPython.utils import io
 from IPython.utils.traitlets import Instance
 from completer import KernelCompleter
 from entry_point import base_launch_kernel, make_argument_parser, make_kernel, \
     start_kernel
 from iostream import OutStream
 from session import Session, Message
 from zmqshell import ZMQInteractiveShell
 
 #-----------------------------------------------------------------------------
 # Main kernel class
 #-----------------------------------------------------------------------------
 
 class Kernel(Configurable):
 
     #---------------------------------------------------------------------------
     # Kernel interface
     #---------------------------------------------------------------------------
 
     shell = Instance('IPython.core.interactiveshell.InteractiveShellABC')
     session = Instance(Session)
     reply_socket = Instance('zmq.Socket')
     pub_socket = Instance('zmq.Socket')
     req_socket = Instance('zmq.Socket')
 
     # Maps user-friendly backend names to matplotlib backend identifiers.
     _pylab_map = { 'tk': 'TkAgg',
                    'gtk': 'GTKAgg',
                    'wx': 'WXAgg',
                    'qt': 'Qt4Agg', # qt3 not supported
                    'qt4': 'Qt4Agg',
                    'payload-svg' : \
                        'module://IPython.zmq.pylab.backend_payload_svg' }
 
     def __init__(self, **kwargs):
         super(Kernel, self).__init__(**kwargs)
 
         # Initialize the InteractiveShell subclass
         self.shell = ZMQInteractiveShell.instance()
         self.shell.displayhook.session = self.session
         self.shell.displayhook.pub_socket = self.pub_socket
 
         # TMP - hack while developing
         self.shell._reply_content = None
 
         # Build dict of handlers for message types
         msg_types = [ 'execute_request', 'complete_request', 
                       'object_info_request', 'prompt_request',
                       'history_request' ]
         self.handlers = {}
         for msg_type in msg_types:
             self.handlers[msg_type] = getattr(self, msg_type)
 
     def activate_pylab(self, backend=None, import_all=True):
         """ Activates pylab in this kernel's namespace.
 
         Parameters:
         -----------
         backend : str, optional
             A valid backend name.
 
         import_all : bool, optional
             If true, an 'import *' is done from numpy and pylab.
         """
         # FIXME: This is adapted from IPython.lib.pylabtools.pylab_activate.
         #        Common functionality should be refactored.
 
         # We must set the desired backend before importing pylab.
         import matplotlib
         if backend:
             backend_id = self._pylab_map[backend]
             if backend_id.startswith('module://'):
                 # Work around bug in matplotlib: matplotlib.use converts the
                 # backend_id to lowercase even if a module name is specified!
                 matplotlib.rcParams['backend'] = backend_id
             else:
                 matplotlib.use(backend_id)
 
         # Import numpy as np/pyplot as plt are conventions we're trying to
         # somewhat standardize on. Making them available to users by default
         # will greatly help this.
         exec ("import numpy\n"
               "import matplotlib\n"
               "from matplotlib import pylab, mlab, pyplot\n"
               "np = numpy\n"
               "plt = pyplot\n"
               ) in self.shell.user_ns
 
         if import_all:
             exec("from matplotlib.pylab import *\n"
                  "from numpy import *\n") in self.shell.user_ns
 
         matplotlib.interactive(True)
 
     def start(self):
         """ Start the kernel main loop.
         """
         while True:
             ident = self.reply_socket.recv()
             assert self.reply_socket.rcvmore(), "Missing message part."
             msg = self.reply_socket.recv_json()
             omsg = Message(msg)
-            print>>sys.__stdout__
-            print>>sys.__stdout__, omsg
+            io.rprint('\n', omsg)
             handler = self.handlers.get(omsg.msg_type, None)
             if handler is None:
-                print >> sys.__stderr__, "UNKNOWN MESSAGE TYPE:", omsg
+                io.rprinte("UNKNOWN MESSAGE TYPE:", omsg)
             else:
                 handler(ident, omsg)
 
     #---------------------------------------------------------------------------
     # Kernel request handlers
     #---------------------------------------------------------------------------
 
     def execute_request(self, ident, parent):
         try:
             code = parent[u'content'][u'code']
         except:
-            print>>sys.__stderr__, "Got bad msg: "
-            print>>sys.__stderr__, Message(parent)
+            io.rprinte("Got bad msg: ")
+            io.rprinte(Message(parent))
             return
         pyin_msg = self.session.msg(u'pyin',{u'code':code}, parent=parent)
         self.pub_socket.send_json(pyin_msg)
 
         try:
             # Replace raw_input. Note that is not sufficient to replace 
             # raw_input in the user namespace.
             raw_input = lambda prompt='': self._raw_input(prompt, ident, parent)
             __builtin__.raw_input = raw_input
 
             # Set the parent message of the display hook and out streams.
             self.shell.displayhook.set_parent(parent)
             sys.stdout.set_parent(parent)
             sys.stderr.set_parent(parent)
 
             # FIXME: runlines calls the exception handler itself.  We should
             # clean this up.
             self.shell._reply_content = None
             self.shell.runlines(code)
         except:
             # FIXME: this code right now isn't being used yet by default,
             # because the runlines() call above directly fires off exception
             # reporting.  This code, therefore, is only active in the scenario
             # where runlines itself has an unhandled exception.  We need to
             # uniformize this, for all exception construction to come from a
             # single location in the codbase.
             etype, evalue, tb = sys.exc_info()
             tb_list = traceback.format_exception(etype, evalue, tb)
             reply_content = self.shell._showtraceback(etype, evalue, tb_list)
         else:
             payload = self.shell.payload_manager.read_payload()
             # Be agressive about clearing the payload because we don't want
             # it to sit in memory until the next execute_request comes in.
             self.shell.payload_manager.clear_payload()
             reply_content = { 'status' : 'ok', 'payload' : payload }
 
         # Compute the prompt information
         prompt_number = self.shell.displayhook.prompt_count
         reply_content['prompt_number'] = prompt_number        
         prompt_string = self.shell.displayhook.prompt1.peek_next_prompt()
         next_prompt = {'prompt_string' : prompt_string,
                        'prompt_number' : prompt_number+1,
                        'input_sep'     : self.shell.displayhook.input_sep}
         reply_content['next_prompt'] = next_prompt
 
         # TMP - fish exception info out of shell, possibly left there by
         # runlines
         if self.shell._reply_content is not None:
             reply_content.update(self.shell._reply_content)
 
         # Flush output before sending the reply.
         sys.stderr.flush()
         sys.stdout.flush()
 
         # Send the reply.
         reply_msg = self.session.msg(u'execute_reply', reply_content, parent)
-        print>>sys.__stdout__, Message(reply_msg)
+        io.rprint(Message(reply_msg))
         self.reply_socket.send(ident, zmq.SNDMORE)
         self.reply_socket.send_json(reply_msg)
         if reply_msg['content']['status'] == u'error':
             self._abort_queue()
 
     def complete_request(self, ident, parent):
-        matches = {'matches' : self._complete(parent),
+        txt, matches = self._complete(parent)
+        matches = {'matches' : matches,
+                   'matched_text' : txt,
                    'status' : 'ok'}
         completion_msg = self.session.send(self.reply_socket, 'complete_reply',
                                            matches, parent, ident)
-        print >> sys.__stdout__, completion_msg
+        io.rprint(completion_msg)
 
     def object_info_request(self, ident, parent):
         context = parent['content']['oname'].split('.')
         object_info = self._object_info(context)
         msg = self.session.send(self.reply_socket, 'object_info_reply',
                                 object_info, parent, ident)
-        print >> sys.__stdout__, msg
+        io.rprint(msg)
 
     def prompt_request(self, ident, parent):
         prompt_number = self.shell.displayhook.prompt_count
         prompt_string = self.shell.displayhook.prompt1.peek_next_prompt()
         content = {'prompt_string' : prompt_string,
                    'prompt_number' : prompt_number+1,
                    'input_sep'     : self.shell.displayhook.input_sep}
         msg = self.session.send(self.reply_socket, 'prompt_reply',
                                 content, parent, ident)
-        print >> sys.__stdout__, msg
+        io.rprint(msg)
 
     def history_request(self, ident, parent):
         output = parent['content']['output']
         index = parent['content']['index']
         raw = parent['content']['raw']
         hist = self.shell.get_history(index=index, raw=raw, output=output)
         content = {'history' : hist}
         msg = self.session.send(self.reply_socket, 'history_reply',
                                 content, parent, ident)
-        print >> sys.__stdout__, msg
+        io.rprint(msg)
         
     #---------------------------------------------------------------------------
     # Protected interface
     #---------------------------------------------------------------------------
 
     def _abort_queue(self):
         while True:
             try:
                 ident = self.reply_socket.recv(zmq.NOBLOCK)
             except zmq.ZMQError, e:
                 if e.errno == zmq.EAGAIN:
                     break
             else:
                 assert self.reply_socket.rcvmore(), "Unexpected missing message part."
                 msg = self.reply_socket.recv_json()
-            print>>sys.__stdout__, "Aborting:"
-            print>>sys.__stdout__, Message(msg)
+            io.rprint("Aborting:\n", Message(msg))
             msg_type = msg['msg_type']
             reply_type = msg_type.split('_')[0] + '_reply'
             reply_msg = self.session.msg(reply_type, {'status' : 'aborted'}, msg)
-            print>>sys.__stdout__, Message(reply_msg)
+            io.rprint(Message(reply_msg))
             self.reply_socket.send(ident,zmq.SNDMORE)
             self.reply_socket.send_json(reply_msg)
             # We need to wait a bit for requests to come in. This can probably
             # be set shorter for true asynchronous clients.
             time.sleep(0.1)
 
     def _raw_input(self, prompt, ident, parent):
         # Flush output before making the request.
         sys.stderr.flush()
         sys.stdout.flush()
 
         # Send the input request.
         content = dict(prompt=prompt)
         msg = self.session.msg(u'input_request', content, parent)
         self.req_socket.send_json(msg)
 
         # Await a response.
         reply = self.req_socket.recv_json()
         try:
             value = reply['content']['value']
         except:
-            print>>sys.__stderr__, "Got bad raw_input reply: "
-            print>>sys.__stderr__, Message(parent)
+            io.rprinte("Got bad raw_input reply: ")
+            io.rprinte(Message(parent))
             value = ''
         return value
     
     def _complete(self, msg):
-        #from IPython.utils.io import rprint  # dbg
-        #rprint('\n\n**MSG**\n\n', msg)  # dbg
-        #import traceback; rprint(''.join(traceback.format_stack())) # dbg
         c = msg['content']
         try:
             cpos = int(c['cursor_pos'])
         except:
             # If we don't get something that we can convert to an integer, at
-            # leasat attempt the completion guessing the cursor is at the end
-            # of the text
+            # least attempt the completion guessing the cursor is at the end of
+            # the text, if there's any, and otherwise of the line
             cpos = len(c['text'])
+            if cpos==0:
+                cpos = len(c['line'])
         return self.shell.complete(c['text'], c['line'], cpos)
 
     def _object_info(self, context):
         symbol, leftover = self._symbol_from_context(context)
         if symbol is not None and not leftover:
             doc = getattr(symbol, '__doc__', '')
         else:
             doc = ''
         object_info = dict(docstring = doc)
         return object_info
 
     def _symbol_from_context(self, context):
         if not context:
             return None, context
 
         base_symbol_string = context[0]
         symbol = self.shell.user_ns.get(base_symbol_string, None)
         if symbol is None:
             symbol = __builtin__.__dict__.get(base_symbol_string, None)
         if symbol is None:
             return None, context
 
         context = context[1:]
         for i, name in enumerate(context):
             new_symbol = getattr(symbol, name, None)
             if new_symbol is None:
                 return symbol, context[i:]
             else:
                 symbol = new_symbol
 
         return symbol, []
 
 #-----------------------------------------------------------------------------
 # Kernel main and launch functions
 #-----------------------------------------------------------------------------
 
 def launch_kernel(xrep_port=0, pub_port=0, req_port=0, independent=False,
                   pylab=False):
     """ Launches a localhost kernel, binding to the specified ports.
 
     Parameters
     ----------
     xrep_port : int, optional
         The port to use for XREP channel.
 
     pub_port : int, optional
         The port to use for the SUB channel.
 
     req_port : int, optional
         The port to use for the REQ (raw input) channel.
 
     independent : bool, optional (default False) 
         If set, the kernel process is guaranteed to survive if this process
         dies. If not set, an effort is made to ensure that the kernel is killed
         when this process dies. Note that in this case it is still good practice
         to kill kernels manually before exiting.
 
     pylab : bool or string, optional (default False)
         If not False, the kernel will be launched with pylab enabled. If a
         string is passed, matplotlib will use the specified backend. Otherwise,
         matplotlib's default backend will be used.
 
     Returns
     -------
     A tuple of form:
         (kernel_process, xrep_port, pub_port, req_port)
     where kernel_process is a Popen object and the ports are integers.
     """
     extra_arguments = []
     if pylab:
         extra_arguments.append('--pylab')
         if isinstance(pylab, basestring):
             extra_arguments.append(pylab)
     return base_launch_kernel('from IPython.zmq.ipkernel import main; main()',
                               xrep_port, pub_port, req_port, independent, 
                               extra_arguments)
 
 def main():
     """ The IPython kernel main entry point.
     """
     parser = make_argument_parser()
     parser.add_argument('--pylab', type=str, metavar='GUI', nargs='?', 
                         const='auto', help = \
 "Pre-load matplotlib and numpy for interactive use. If GUI is not \
 given, the GUI backend is matplotlib's, otherwise use one of: \
 ['tk', 'gtk', 'qt', 'wx', 'payload-svg'].")
     namespace = parser.parse_args()
 
     kernel = make_kernel(namespace, Kernel, OutStream)
     if namespace.pylab:
         if namespace.pylab == 'auto':
             kernel.activate_pylab()
         else:
             kernel.activate_pylab(namespace.pylab)
     
     start_kernel(namespace, kernel)
 
 if __name__ == '__main__':
     main()