diff --git a/IPython/core/inputtransformer.py b/IPython/core/inputtransformer.py
new file mode 100644
index 0000000..2aff3e8
--- /dev/null
+++ b/IPython/core/inputtransformer.py
@@ -0,0 +1,112 @@
+import abc
+import re
+
+from IPython.core.splitinput import split_user_input, LineInfo
+from IPython.core.inputsplitter import (ESC_SHELL, ESC_SH_CAP, ESC_HELP,
+                                        ESC_HELP2, ESC_MAGIC, ESC_MAGIC2,
+                                        ESC_QUOTE, ESC_QUOTE2, ESC_PAREN)
+from IPython.core.inputsplitter import EscapedTransformer, _make_help_call, has_comment
+
+class InputTransformer(object):
+    __metaclass__ = abc.ABCMeta
+    
+    @abc.abstractmethod
+    def push(self, line):
+        pass
+    
+    @abc.abstractmethod
+    def reset(self):
+        pass
+
+class StatelessInputTransformer(InputTransformer):
+    """Decorator for a stateless input transformer implemented as a function."""
+    def __init__(self, func):
+        self.func = func
+    
+    def push(self, line):
+        return self.func(line)
+    
+    def reset(self):
+        pass
+
+class CoroutineInputTransformer(InputTransformer):
+    """Decorator for an input transformer implemented as a coroutine."""
+    def __init__(self, coro):
+        # Prime it
+        self.coro = coro()
+        next(self.coro)
+    
+    def push(self, line):
+        return self.coro.send(line)
+    
+    def reset(self):
+        self.coro.send(None)
+
+@CoroutineInputTransformer
+def escaped_transformer():
+    et = EscapedTransformer()
+    line = ''
+    while True:
+        line = (yield line)
+        if not line or line.isspace():
+            continue
+        lineinf = LineInfo(line)
+        if lineinf.esc not in et.tr:
+            continue
+        
+        parts = []
+        while line is not None:
+            parts.append(line.rstrip('\\'))
+            if not line.endswith('\\'):
+                break
+            line = (yield None)
+        
+        # Output
+        lineinf = LineInfo(' '.join(parts))
+        line = et.tr[lineinf.esc](lineinf)
+
+_initial_space_re = re.compile(r'\s*')
+
+_help_end_re = re.compile(r"""(%{0,2}
+                              [a-zA-Z_*][\w*]*        # Variable name
+                              (\.[a-zA-Z_*][\w*]*)*   # .etc.etc
+                              )
+                              (\?\??)$                # ? or ??""",
+                              re.VERBOSE)
+
+@StatelessInputTransformer
+def transform_help_end(line):
+    """Translate lines with ?/?? at the end"""
+    m = _help_end_re.search(line)
+    if m is None or has_comment(line):
+        return line
+    target = m.group(1)
+    esc = m.group(3)
+    lspace = _initial_space_re.match(line).group(0)
+
+    # If we're mid-command, put it back on the next prompt for the user.
+    next_input = line.rstrip('?') if line.strip() != m.group(0) else None
+
+    return _make_help_call(target, esc, lspace, next_input)
+    
+                
+@CoroutineInputTransformer
+def cellmagic():
+    tpl = 'get_ipython().run_cell_magic(%r, %r, %r)'
+    line = ''
+    while True:
+        line = (yield line)
+        if not line.startswith(ESC_MAGIC2):
+            continue
+        
+        first = line
+        body = []
+        line = (yield None)
+        while (line is not None) and (line.strip() != ''):
+            body.append(line)
+            line = (yield None)
+        
+        # Output
+        magic_name, _, first = first.partition(' ')
+        magic_name = magic_name.lstrip(ESC_MAGIC2)
+        line = tpl % (magic_name, first, '\n'.join(body))
diff --git a/IPython/core/tests/test_inputtransformer.py b/IPython/core/tests/test_inputtransformer.py
new file mode 100644
index 0000000..7907753
--- /dev/null
+++ b/IPython/core/tests/test_inputtransformer.py
@@ -0,0 +1,37 @@
+import unittest
+import nose.tools as nt
+
+from IPython.testing import tools as tt
+from IPython.utils import py3compat
+
+from IPython.core import inputtransformer
+from IPython.core.tests.test_inputsplitter import syntax
+
+def wrap_transform(transformer):
+    def transform(inp):
+        for line in inp:
+            res = transformer.push(line)
+            if res is not None:
+                return res
+        return transformer.push(None)
+    
+    return transform
+
+cellmagic_tests = [
+(['%%foo a'], "get_ipython().run_cell_magic('foo', 'a', '')"),
+(['%%bar 123', 'hello', ''], "get_ipython().run_cell_magic('bar', '123', 'hello')"),
+]
+
+def test_transform_cellmagic():
+    tt.check_pairs(wrap_transform(inputtransformer.cellmagic), cellmagic_tests)
+
+esctransform_tests = [(i, py3compat.u_format(o)) for i,o in [
+(['%pdef zip'], "get_ipython().magic({u}'pdef zip')"),
+(['%abc def \\', 'ghi'], "get_ipython().magic({u}'abc def  ghi')"),
+]]
+
+def test_transform_escaped():
+    tt.check_pairs(wrap_transform(inputtransformer.escaped_transformer), esctransform_tests)
+
+def endhelp_test():
+    tt.check_pairs(inputtransformer.transform_help_end.push, syntax['end_help'])