add InteractiveShell.display_page config

sends all pager output to regular output instead of pager

pagers are registered via the already-existing show_in_pager hook,
rather than clobbering like we used to do in `install_payload_page`

IPython/core/interactiveshell.py

@@ -72,7 +72,7 b' from IPython.utils.strdispatch import StrDispatch'
 from IPython.utils.syspathcontext import prepended_to_syspath
 from IPython.utils.text import (format_screen, LSString, SList,
                                 DollarFormatter)
-from IPython.utils.traitlets import (Integer, CBool, CaselessStrEnum, Enum,
+from IPython.utils.traitlets import (Integer, Bool, CBool, CaselessStrEnum, Enum,
                                      List, Unicode, Instance, Type)
 from IPython.utils.warn import warn, error
 import IPython.core.hooks
@@ -334,6 +334,10 b' class InteractiveShell(SingletonConfigurable):'
     multiline_history = CBool(sys.platform != 'win32', config=True,
         help="Save multi-line entries as one entry in readline history"
     )
+    display_page = Bool(False, config=True,
+        help="""If True, anything that would be passed to the pager
+        will be displayed as regular output instead."""
+    )
 
     # deprecated prompt traits:
     
@@ -821,6 +825,9 b' class InteractiveShell(SingletonConfigurable):'
             # 0-100 priority
             self.set_hook(hook_name,getattr(hooks,hook_name), 100, _warn_deprecated=False)
 
+        if self.display_page:
+            self.set_hook('show_in_pager', page.as_hook(page.display_page), 90)
+    
     def set_hook(self,name,hook, priority=50, str_key=None, re_key=None,
                  _warn_deprecated=True):
         """set_hook(name,hook) -> sets an internal IPython hook.

IPython/core/page.py

@@ -2,29 +2,17 b''
 """
 Paging capabilities for IPython.core
 
-Authors:
-
-* Brian Granger
-* Fernando Perez
-
 Notes
 -----
 
-For now this uses ipapi, so it can't be in IPython.utils.  If we can get
+For now this uses IPython hooks, so it can't be in IPython.utils.  If we can get
 rid of that dependency, we could move it there.
 -----
 """
 
-#-----------------------------------------------------------------------------
-#  Copyright (C) 2008-2011  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.
-#-----------------------------------------------------------------------------
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
 
-#-----------------------------------------------------------------------------
-# Imports
-#-----------------------------------------------------------------------------
 from __future__ import print_function
 
 import os
@@ -35,6 +23,7 b' import tempfile'
 from io import UnsupportedOperation
 
 from IPython import get_ipython
+from IPython.core.display import display
 from IPython.core.error import TryNext
 from IPython.utils.data import chop
 from IPython.utils import io
@@ -43,9 +32,24 b' from IPython.utils.terminal import get_terminal_size'
 from IPython.utils import py3compat
 
 
-#-----------------------------------------------------------------------------
-# Classes and functions
-#-----------------------------------------------------------------------------
+def display_page(strng, start=0, screen_lines=25):
+    """Just display, no paging. screen_lines is ignored."""
+    if isinstance(strng, dict):
+        data = strng
+    else:
+        if start:
+            strng = u'\n'.join(strng.splitlines()[start:])
+        data = {'text/plain': strng}
+    display(data, raw=True)
+
+
+def as_hook(page_func):
+    """Wrap a pager func to strip the `self` arg
+    
+    so it can be called as a hook.
+    """
+    return lambda self, *args, **kwargs: page_func(*args, **kwargs)
+
 
 esc_re = re.compile(r"(\x1b[^m]+m)")
 
@@ -132,7 +136,7 b' def _detect_screen_size(screen_lines_def):'
     #print '***Screen size:',screen_lines_real,'lines x',\
     #screen_cols,'columns.' # dbg
 
-def page(strng, start=0, screen_lines=0, pager_cmd=None):
+def pager_page(strng, start=0, screen_lines=0, pager_cmd=None):
     """Display a string, piping through a pager after a certain length.
     
     strng can be a mime-bundle dict, supplying multiple representations,
@@ -164,15 +168,6 b' def page(strng, start=0, screen_lines=0, pager_cmd=None):'
     # negative value.  Offset to 0 for robustness.
     start = max(0, start)
 
-    # first, try the hook
-    ip = get_ipython()
-    if ip:
-        try:
-            ip.hooks.show_in_pager(strng)
-            return
-        except TryNext:
-            pass
-
     # Ugly kludge, but calling curses.initscr() flat out crashes in emacs
     TERM = os.environ.get('TERM','dumb')
     if TERM in ['dumb','emacs'] and os.name != 'nt':
@@ -252,6 +247,32 b' def page(strng, start=0, screen_lines=0, pager_cmd=None):'
             page_dumb(strng,screen_lines=screen_lines)
 
 
+def page(data, start=0, screen_lines=0, pager_cmd=None):
+    """Display content in a pager, piping through a pager after a certain length.
+    
+    data can be a mime-bundle dict, supplying multiple representations,
+    keyed by mime-type, or text.
+    
+    Pager is dispatched via the `show_in_pager` IPython hook.
+    If no hook is registered, `pager_page` will be used.
+    """
+    # Some routines may auto-compute start offsets incorrectly and pass a
+    # negative value.  Offset to 0 for robustness.
+    start = max(0, start)
+
+    # first, try the hook
+    ip = get_ipython()
+    if ip:
+        try:
+            ip.hooks.show_in_pager(data, start=start, screen_lines=screen_lines)
+            return
+        except TryNext:
+            pass
+    
+    # fallback on default pager
+    return pager_page(data, start, screen_lines, pager_cmd)
+
+
 def page_file(fname, start=0, pager_cmd=None):
     """Page a file, using an optional pager command and starting line.
     """

IPython/core/payloadpage.py

@@ -4,11 +4,9 b''
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
+import warnings
 from IPython.core.getipython import get_ipython
 
-#-----------------------------------------------------------------------------
-# Classes and functions
-#-----------------------------------------------------------------------------
 
 def page(strng, start=0, screen_lines=0, pager_cmd=None):
     """Print a string, piping through a pager.
@@ -43,6 +41,12 b' def page(strng, start=0, screen_lines=0, pager_cmd=None):'
 
 
 def install_payload_page():
-    """Install this version of page as IPython.core.page.page."""
+    """DEPRECATED, use show_in_pager hook
+    
+    Install this version of page as IPython.core.page.page.
+    """
+    warnings.warn("""install_payload_page is deprecated.
+    Use `ip.set_hook('show_in_pager, page.as_hook(payloadpage.page))`
+    """)
     from IPython.core import page as corepage
     corepage.page = page

IPython/kernel/zmq/zmqshell.py

@@ -31,7 +31,7 b' from IPython.core.displaypub import DisplayPublisher'
 from IPython.core.error import UsageError
 from IPython.core.magics import MacroToEdit, CodeMagics
 from IPython.core.magic import magics_class, line_magic, Magics
-from IPython.core.payloadpage import install_payload_page
+from IPython.core import payloadpage
 from IPython.core.usage import default_gui_banner
 from IPython.display import display, Javascript
 from IPython.kernel.inprocess.socket import SocketABC
@@ -391,9 +391,7 b' class ZMQInteractiveShell(InteractiveShell):'
             raise UsageError("%s" % e)
 
     def init_environment(self):
-        """Configure the user's environment.
-
-        """
+        """Configure the user's environment."""
         env = os.environ
         # These two ensure 'ls' produces nice coloring on BSD-derived systems
         env['TERM'] = 'xterm-color'
@@ -404,8 +402,9 b' class ZMQInteractiveShell(InteractiveShell):'
         env['PAGER'] = 'cat'
         env['GIT_PAGER'] = 'cat'
         
-        # And install the payload version of page.
-        install_payload_page()
+    def init_hooks(self):
+        super(ZMQInteractiveShell, self).init_hooks()
+        self.set_hook('show_in_pager', page.as_hook(payloadpage.page), 99)
 
     def ask_exit(self):
         """Engage the exit actions."""