Backport PR #4120: support `input` in Python 2 kernels

input is just `eval(raw_input(…))`

closes  #3990

IPython/kernel/tests/test_kernel.py

@@ -24,7 +24,7 b' import nose.tools as nt'
 from IPython.kernel import KernelManager
 from IPython.kernel.tests.test_message_spec import execute, flush_channels
 from IPython.testing import decorators as dec
-from IPython.utils import path
+from IPython.utils import path, py3compat
 
 #-------------------------------------------------------------------------------
 # Tests
@@ -33,6 +33,9 b' IPYTHONDIR = None'
 save_env = None
 save_get_ipython_dir = None
 
+STARTUP_TIMEOUT = 60
+TIMEOUT = 15
+
 def setup():
     """setup temporary IPYTHONDIR for tests"""
     global IPYTHONDIR
@@ -75,7 +78,7 b' def new_kernel():'
 
     # wait for kernel to be ready
     KC.shell_channel.execute("import sys")
-    KC.shell_channel.get_msg(block=True, timeout=5)
+    KC.shell_channel.get_msg(block=True, timeout=STARTUP_TIMEOUT)
     flush_channels(KC)
     try:
         yield KC
@@ -116,6 +119,8 b' def _check_mp_mode(kc, expected=False, stream="stdout"):'
     nt.assert_equal(eval(stdout.strip()), expected)
 
 
+# printing tests
+
 def test_simple_print():
     """simple print statement in kernel"""
     with new_kernel() as kc:
@@ -125,7 +130,6 b' def test_simple_print():'
         nt.assert_equal(stdout, 'hi\n')
         nt.assert_equal(stderr, '')
         _check_mp_mode(kc, expected=False)
-    print ('hello')
 
 
 @dec.knownfailureif(sys.platform == 'win32', "subprocess prints fail on Windows")
@@ -201,3 +205,47 b' def test_subprocess_error():'
 
         _check_mp_mode(kc, expected=False)
         _check_mp_mode(kc, expected=False, stream="stderr")
+
+
+# raw_input tests
+
+def test_raw_input():
+    """test [raw_]input"""
+    with new_kernel() as kc:
+        iopub = kc.iopub_channel
+
+        input_f = "input" if py3compat.PY3 else "raw_input"
+        theprompt = "prompt> "
+        code = 'print({input_f}("{theprompt}"))'.format(**locals())
+        msg_id = kc.execute(code, allow_stdin=True)
+        msg = kc.get_stdin_msg(block=True, timeout=TIMEOUT)
+        nt.assert_equal(msg['header']['msg_type'], u'input_request')
+        content = msg['content']
+        nt.assert_equal(content['prompt'], theprompt)
+        text = "some text"
+        kc.input(text)
+        reply = kc.get_shell_msg(block=True, timeout=TIMEOUT)
+        nt.assert_equal(reply['content']['status'], 'ok')
+        stdout, stderr = assemble_output(iopub)
+        nt.assert_equal(stdout, text + "\n")
+
+
[e-mail](py3compat.PY3)
+def test_eval_input():
+    """test input() on Python 2"""
+    with new_kernel() as kc:
+        iopub = kc.iopub_channel
+
+        input_f = "input" if py3compat.PY3 else "raw_input"
+        theprompt = "prompt> "
+        code = 'print(input("{theprompt}"))'.format(**locals())
+        msg_id = kc.execute(code, allow_stdin=True)
+        msg = kc.get_stdin_msg(block=True, timeout=TIMEOUT)
+        nt.assert_equal(msg['header']['msg_type'], u'input_request')
+        content = msg['content']
+        nt.assert_equal(content['prompt'], theprompt)
+        kc.input("1+1")
+        reply = kc.get_shell_msg(block=True, timeout=TIMEOUT)
+        nt.assert_equal(reply['content']['status'], 'ok')
+        stdout, stderr = assemble_output(iopub)
+        nt.assert_equal(stdout, "2\n")

IPython/kernel/zmq/ipkernel.py

@@ -131,6 +131,7 b' class Kernel(Configurable):'
     # A reference to the Python builtin 'raw_input' function.
     # (i.e., __builtin__.raw_input for Python 2.7, builtins.input for Python 3)
     _sys_raw_input = Any()
+    _sys_eval_input = Any()
 
     # set of aborted msg_ids
     aborted = Set()
@@ -352,15 +353,18 b' class Kernel(Configurable):'
         # raw_input in the user namespace.
         if content.get('allow_stdin', False):
             raw_input = lambda prompt='': self._raw_input(prompt, ident, parent)
+            input = lambda prompt='': eval(raw_input(prompt))
         else:
-            raw_input = lambda prompt='' : self._no_raw_input()
+            raw_input = input = lambda prompt='' : self._no_raw_input()
 
         if py3compat.PY3:
             self._sys_raw_input = __builtin__.input
             __builtin__.input = raw_input
         else:
             self._sys_raw_input = __builtin__.raw_input
+            self._sys_eval_input = __builtin__.input
             __builtin__.raw_input = raw_input
+            __builtin__.input = input
 
         # Set the parent message of the display hook and out streams.
         shell.displayhook.set_parent(parent)
@@ -403,6 +407,7 b' class Kernel(Configurable):'
                  __builtin__.input = self._sys_raw_input
              else:
                  __builtin__.raw_input = self._sys_raw_input
+                 __builtin__.input = self._sys_eval_input
 
         reply_content[u'status'] = status
 

examples/notebooks/Frontend-Kernel Model.ipynb

@@ -1,6 +1,6 b''
 {
  "metadata": {
-  "name": "Frontend-Kernel Model"
+  "name": ""
  },
  "nbformat": 3,
  "nbformat_minor": 0,
@@ -152,6 +152,21 b''
      "cell_type": "code",
      "collapsed": false,
      "input": [
+      "# Python 3 compat\n",
+      "try:\n",
+      "    raw_input\n",
+      "except NameError:\n",
+      "    raw_input = input"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
       "name = raw_input(\"What is your name? \")\n",
       "name"
      ],
@@ -169,13 +184,49 b''
       {
        "metadata": {},
        "output_type": "pyout",
-       "prompt_number": 1,
+       "prompt_number": 2,
        "text": [
-        "u'Sir Robin'"
+        "'Sir Robin'"
        ]
       }
      ],
-     "prompt_number": 1
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "**Python 2-only**: the eval input works as well (`input` is just `eval(raw_input(prompt))`)"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "fingers = input(\"How many fingers? \")\n",
+      "fingers, type(fingers)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "name": "stdout",
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "How many fingers? 4\n"
+       ]
+      },
+      {
+       "metadata": {},
+       "output_type": "pyout",
+       "prompt_number": 3,
+       "text": [
+        "(4, int)"
+       ]
+      }
+     ],
+     "prompt_number": 3
     },
     {
      "cell_type": "code",
@@ -195,13 +246,13 b''
        "output_type": "pyerr",
        "traceback": [
         "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[1;31mZeroDivisionError\u001b[0m                         Traceback (most recent call last)",
-        "\u001b[1;32m<ipython-input-2-a5097cc0c0c5>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m()\u001b[0m\n\u001b[0;32m      2\u001b[0m     \u001b[1;32mreturn\u001b[0m \u001b[0mx\u001b[0m\u001b[1;33m/\u001b[0m\u001b[0my\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m      3\u001b[0m \u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 4\u001b[1;33m \u001b[0mdiv\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;36m1\u001b[0m\u001b[1;33m,\u001b[0m\u001b[1;36m0\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
-        "\u001b[1;32m<ipython-input-2-a5097cc0c0c5>\u001b[0m in \u001b[0;36mdiv\u001b[1;34m(x, y)\u001b[0m\n\u001b[0;32m      1\u001b[0m \u001b[1;32mdef\u001b[0m \u001b[0mdiv\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mx\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0my\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 2\u001b[1;33m     \u001b[1;32mreturn\u001b[0m \u001b[0mx\u001b[0m\u001b[1;33m/\u001b[0m\u001b[0my\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m      3\u001b[0m \u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m      4\u001b[0m \u001b[0mdiv\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;36m1\u001b[0m\u001b[1;33m,\u001b[0m\u001b[1;36m0\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",
+        "\u001b[1;32m<ipython-input-4-a5097cc0c0c5>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m()\u001b[0m\n\u001b[0;32m      2\u001b[0m     \u001b[1;32mreturn\u001b[0m \u001b[0mx\u001b[0m\u001b[1;33m/\u001b[0m\u001b[0my\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m      3\u001b[0m \u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 4\u001b[1;33m \u001b[0mdiv\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;36m1\u001b[0m\u001b[1;33m,\u001b[0m\u001b[1;36m0\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
+        "\u001b[1;32m<ipython-input-4-a5097cc0c0c5>\u001b[0m in \u001b[0;36mdiv\u001b[1;34m(x, y)\u001b[0m\n\u001b[0;32m      1\u001b[0m \u001b[1;32mdef\u001b[0m \u001b[0mdiv\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mx\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0my\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 2\u001b[1;33m     \u001b[1;32mreturn\u001b[0m \u001b[0mx\u001b[0m\u001b[1;33m/\u001b[0m\u001b[0my\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m      3\u001b[0m \u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m      4\u001b[0m \u001b[0mdiv\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;36m1\u001b[0m\u001b[1;33m,\u001b[0m\u001b[1;36m0\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",
         "\u001b[1;31mZeroDivisionError\u001b[0m: integer division or modulo by zero"
        ]
       }
      ],
-     "prompt_number": 2
+     "prompt_number": 4
     },
     {
      "cell_type": "code",
@@ -216,7 +267,7 b''
        "output_type": "stream",
        "stream": "stdout",
        "text": [
-        "> \u001b[1;32m<ipython-input-2-a5097cc0c0c5>\u001b[0m(2)\u001b[0;36mdiv\u001b[1;34m()\u001b[0m\n",
+        "> \u001b[1;32m<ipython-input-4-a5097cc0c0c5>\u001b[0m(2)\u001b[0;36mdiv\u001b[1;34m()\u001b[0m\n",
         "\u001b[1;32m      1 \u001b[1;33m\u001b[1;32mdef\u001b[0m \u001b[0mdiv\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mx\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0my\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",
         "\u001b[0m\u001b[1;32m----> 2 \u001b[1;33m    \u001b[1;32mreturn\u001b[0m \u001b[0mx\u001b[0m\u001b[1;33m/\u001b[0m\u001b[0my\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",
         "\u001b[0m\u001b[1;32m      3 \u001b[1;33m\u001b[1;33m\u001b[0m\u001b[0m\n",
@@ -262,7 +313,7 b''
        ]
       }
      ],
-     "prompt_number": 3
+     "prompt_number": 5
     }
    ],
    "metadata": {}