Merge pull request #4561 from minrk/for_type_clear

Copied some of the logic from apptools (thanks @rkern).

The current behavior:

- `lookup(instance)` - return appropriate callback or a given object
- `lookup_by_type(type_or_str)` - return appropriate callback for a given type or `'mod.name'` type string
- `for_type(type_or_str)` - behaves the same, only adding support for type strings for consistency
- `pop(type_or_str[, default])` - remove a type (by type or string)
- `typ_or_str in Formatter` checks whether a type is registered, checking with `lookup_by_type`

The inner structures remain unchanged.

docs/source/whatsnew/pr/formatters.txt

@@ -0,0 +1,20 b''
+DisplayFormatter changes
+========================
+
+There was no official way to query or remove callbacks in the Formatter API.
+To remedy this, the following methods are added to :class:`BaseFormatter`:
+
+- ``lookup(instance)`` - return appropriate callback or a given object
+- ``lookup_by_type(type_or_str)`` - return appropriate callback for a given type or ``'mod.name'`` type string
+- ``pop(type_or_str)`` - remove a type (by type or string).
+  Pass a second argument to avoid KeyError (like dict).
+
+All of the above methods raise a KeyError if no match is found.
+
+And the following methods are changed:
+
+- ``for_type(type_or_str)`` - behaves the same as before, only adding support for ``'mod.name'``
+  type strings in addition to plain types. This removes the need for ``for_type_by_name()``,
+  but it remains for backward compatibility.
+
+

IPython/core/formatters.py

@@ -1,654 +1,791 b''
 # -*- coding: utf-8 -*-
 """Display formatters.
 
 Inheritance diagram:
 
 .. inheritance-diagram:: IPython.core.formatters
    :parts: 3
 
 Authors:
 
 * Robert Kern
 * Brian Granger
 """
 #-----------------------------------------------------------------------------
 # Copyright (C) 2010-2011, IPython Development Team.
 #
 # Distributed under the terms of the Modified BSD License.
 #
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 # Stdlib imports
 import abc
 import sys
 import warnings
 
 # Our own imports
 from IPython.config.configurable import Configurable
 from IPython.lib import pretty
 from IPython.utils.traitlets import (
     Bool, Dict, Integer, Unicode, CUnicode, ObjectName, List,
 )
-from IPython.utils.py3compat import unicode_to_str, with_metaclass, PY3
+from IPython.utils.py3compat import (
+    unicode_to_str, with_metaclass, PY3, string_types,
+)
 
 if PY3:
     from io import StringIO
 else:
     from StringIO import StringIO
 
 
 #-----------------------------------------------------------------------------
 # The main DisplayFormatter class
 #-----------------------------------------------------------------------------
 
-
 class DisplayFormatter(Configurable):
 
     # When set to true only the default plain text formatter will be used.
     plain_text_only = Bool(False, config=True)
     def _plain_text_only_changed(self, name, old, new):
         warnings.warn("""DisplayFormatter.plain_text_only is deprecated.
         
         Use DisplayFormatter.active_types = ['text/plain']
         for the same effect.
         """, DeprecationWarning)
         if new:
             self.active_types = ['text/plain']
         else:
             self.active_types = self.format_types
     
     active_types = List(Unicode, config=True,
         help="""List of currently active mime-types to display.
         You can use this to set a white-list for formats to display.
         
         Most users will not need to change this value.
         """)
     def _active_types_default(self):
         return self.format_types
     
     def _active_types_changed(self, name, old, new):
         for key, formatter in self.formatters.items():
             if key in new:
                 formatter.enabled = True
             else:
                 formatter.enabled = False
     
     # A dict of formatter whose keys are format types (MIME types) and whose
     # values are subclasses of BaseFormatter.
     formatters = Dict()
     def _formatters_default(self):
         """Activate the default formatters."""
         formatter_classes = [
             PlainTextFormatter,
             HTMLFormatter,
             SVGFormatter,
             PNGFormatter,
             JPEGFormatter,
             LatexFormatter,
             JSONFormatter,
             JavascriptFormatter
         ]
         d = {}
         for cls in formatter_classes:
             f = cls(parent=self)
             d[f.format_type] = f
         return d
 
     def format(self, obj, include=None, exclude=None):
         """Return a format data dict for an object.
 
         By default all format types will be computed.
 
         The following MIME types are currently implemented:
 
         * text/plain
         * text/html
         * text/latex
         * application/json
         * application/javascript
         * image/png
         * image/jpeg
         * image/svg+xml
 
         Parameters
         ----------
         obj : object
             The Python object whose format data will be computed.
         include : list or tuple, optional
             A list of format type strings (MIME types) to include in the
             format data dict. If this is set *only* the format types included
             in this list will be computed.
         exclude : list or tuple, optional
             A list of format type string (MIME types) to exclude in the format
             data dict. If this is set all format types will be computed,
             except for those included in this argument.
 
         Returns
         -------
         (format_dict, metadata_dict) : tuple of two dicts
         
             format_dict is a dictionary of key/value pairs, one of each format that was
             generated for the object. The keys are the format types, which
             will usually be MIME type strings and the values and JSON'able
             data structure containing the raw data for the representation in
             that format.
             
             metadata_dict is a dictionary of metadata about each mime-type output.
             Its keys will be a strict subset of the keys in format_dict.
         """
         format_dict = {}
         md_dict = {}
 
         for format_type, formatter in self.formatters.items():
             if include and format_type not in include:
                 continue
             if exclude and format_type in exclude:
                 continue
             
             md = None
             try:
                 data = formatter(obj)
             except:
                 # FIXME: log the exception
                 raise
             
             # formatters can return raw data or (data, metadata)
             if isinstance(data, tuple) and len(data) == 2:
                 data, md = data
             
             if data is not None:
                 format_dict[format_type] = data
             if md is not None:
                 md_dict[format_type] = md
             
         return format_dict, md_dict
 
     @property
     def format_types(self):
         """Return the format types (MIME types) of the active formatters."""
         return list(self.formatters.keys())
 
 
 #-----------------------------------------------------------------------------
 # Formatters for specific format types (text, html, svg, etc.)
 #-----------------------------------------------------------------------------
 
 
 class FormatterABC(with_metaclass(abc.ABCMeta, object)):
     """ Abstract base class for Formatters.
 
     A formatter is a callable class that is responsible for computing the
     raw format data for a particular format type (MIME type). For example,
     an HTML formatter would have a format type of `text/html` and would return
     the HTML representation of the object when called.
     """
 
     # The format type of the data returned, usually a MIME type.
     format_type = 'text/plain'
 
     # Is the formatter enabled...
     enabled = True
 
     @abc.abstractmethod
     def __call__(self, obj):
         """Return a JSON'able representation of the object.
 
         If the object cannot be formatted by this formatter, then return None
         """
         try:
             return repr(obj)
         except Exception:
             return None
 
 
+def _mod_name_key(typ):
+    """Return a (__module__, __name__) tuple for a type.
+    
+    Used as key in Formatter.deferred_printers.
+    """
+    module = getattr(typ, '__module__', None)
+    name = getattr(typ, '__name__', None)
+    return (module, name)
+
+
+def _get_type(obj):
+    """Return the type of an instance (old and new-style)"""
+    return getattr(obj, '__class__', None) or type(obj)
+
+_raise_key_error = object()
+
 class BaseFormatter(Configurable):
     """A base formatter class that is configurable.
 
     This formatter should usually be used as the base class of all formatters.
     It is a traited :class:`Configurable` class and includes an extensible
     API for users to determine how their objects are formatted. The following
     logic is used to find a function to format an given object.
 
     1. The object is introspected to see if it has a method with the name
        :attr:`print_method`. If is does, that object is passed to that method
        for formatting.
     2. If no print method is found, three internal dictionaries are consulted
        to find print method: :attr:`singleton_printers`, :attr:`type_printers`
        and :attr:`deferred_printers`.
 
     Users should use these dictionaries to register functions that will be
     used to compute the format data for their objects (if those objects don't
     have the special print methods). The easiest way of using these
     dictionaries is through the :meth:`for_type` and :meth:`for_type_by_name`
     methods.
 
     If no function/callable is found to compute the format data, ``None`` is
     returned and this format type is not used.
     """
 
     format_type = Unicode('text/plain')
 
     enabled = Bool(True, config=True)
 
     print_method = ObjectName('__repr__')
 
     # The singleton printers.
     # Maps the IDs of the builtin singleton objects to the format functions.
     singleton_printers = Dict(config=True)
-    def _singleton_printers_default(self):
-        return {}
 
     # The type-specific printers.
     # Map type objects to the format functions.
     type_printers = Dict(config=True)
-    def _type_printers_default(self):
-        return {}
 
     # The deferred-import type-specific printers.
     # Map (modulename, classname) pairs to the format functions.
     deferred_printers = Dict(config=True)
-    def _deferred_printers_default(self):
-        return {}
 
     def __call__(self, obj):
         """Compute the format for an object."""
         if self.enabled:
-            obj_id = id(obj)
             try:
-                obj_class = getattr(obj, '__class__', None) or type(obj)
-                # First try to find registered singleton printers for the type.
+                # lookup registered printer
                 try:
-                    printer = self.singleton_printers[obj_id]
-                except (TypeError, KeyError):
+                    printer = self.lookup(obj)
+                except KeyError:
                     pass
                 else:
                     return printer(obj)
-                # Next look for type_printers.
-                for cls in pretty._get_mro(obj_class):
-                    if cls in self.type_printers:
-                        return self.type_printers[cls](obj)
-                    else:
-                        printer = self._in_deferred_types(cls)
-                        if printer is not None:
-                            return printer(obj)
-                # Finally look for special method names.
-                if hasattr(obj_class, self.print_method):
-                    printer = getattr(obj_class, self.print_method)
-                    return printer(obj)
+                # Finally look for special method names
+                method = pretty._safe_getattr(obj, self.print_method, None)
+                if method is not None:
+                    return method()
                 return None
             except Exception:
                 pass
         else:
             return None
+    
+    def __contains__(self, typ):
+        """map in to lookup_by_type"""
+        try:
+            self.lookup_by_type(typ)
+        except KeyError:
+            return False
+        else:
+            return True
+    
+    def lookup(self, obj):
+        """Look up the formatter for a given instance.
+        
+        Parameters
+        ----------
+        obj  : object instance
 
-    def for_type(self, typ, func):
-        """Add a format function for a given type.
+        Returns
+        -------
+        f : callable
+            The registered formatting callable for the type.
+
+        Raises
+        ------
+        KeyError if the type has not been registered.
+        """
+        # look for singleton first
+        obj_id = id(obj)
+        if obj_id in self.singleton_printers:
+            return self.singleton_printers[obj_id]
+        # then lookup by type
+        return self.lookup_by_type(_get_type(obj))
+    
+    def lookup_by_type(self, typ):
+        """Look up the registered formatter for a type.
+
+        Parameters
+        ----------
+        typ  : type or '__module__.__name__' string for a type
+
+        Returns
+        -------
+        f : callable
+            The registered formatting callable for the type.
+
+        Raises
+        ------
+        KeyError if the type has not been registered.
+        """
+        if isinstance(typ, string_types):
+            typ_key = tuple(typ.rsplit('.',1))
+            if typ_key not in self.deferred_printers:
+                # We may have it cached in the type map. We will have to
+                # iterate over all of the types to check.
+                for cls in self.type_printers:
+                    if _mod_name_key(cls) == typ_key:
+                        return self.type_printers[cls]
+            else:
+                return self.deferred_printers[typ_key]
+        else:
+            for cls in pretty._get_mro(typ):
+                if cls in self.type_printers or self._in_deferred_types(cls):
+                    return self.type_printers[cls]
+        
+        # If we have reached here, the lookup failed.
+        raise KeyError("No registered printer for {0!r}".format(typ))
 
+    def for_type(self, typ, func=None):
+        """Add a format function for a given type.
+        
         Parameters
         -----------
-        typ : class
+        typ : type or '__module__.__name__' string for a type
             The class of the object that will be formatted using `func`.
         func : callable
-            The callable that will be called to compute the format data. The
-            call signature of this function is simple, it must take the
-            object to be formatted and return the raw data for the given
-            format. Subclasses may use a different call signature for the
+            A callable for computing the format data.
+            `func` will be called with the object to be formatted,
+            and will return the raw data in this formatter's format.
+            Subclasses may use a different call signature for the
             `func` argument.
+            
+            If `func` is None or not specified, there will be no change,
+            only returning the current value.
+        
+        Returns
+        -------
+        oldfunc : callable
+            The currently registered callable.
+            If you are registering a new formatter,
+            this will be the previous value (to enable restoring later).
         """
-        oldfunc = self.type_printers.get(typ, None)
+        # if string given, interpret as 'pkg.module.class_name'
+        if isinstance(typ, string_types):
+            type_module, type_name = typ.rsplit('.', 1)
+            return self.for_type_by_name(type_module, type_name, func)
+        
+        try:
+            oldfunc = self.lookup_by_type(typ)
+        except KeyError:
+            oldfunc = None
+        
         if func is not None:
-            # To support easy restoration of old printers, we need to ignore
-            # Nones.
             self.type_printers[typ] = func
+        
         return oldfunc
 
-    def for_type_by_name(self, type_module, type_name, func):
+    def for_type_by_name(self, type_module, type_name, func=None):
         """Add a format function for a type specified by the full dotted
         module and name of the type, rather than the type of the object.
 
         Parameters
         ----------
         type_module : str
             The full dotted name of the module the type is defined in, like
             ``numpy``.
         type_name : str
             The name of the type (the class name), like ``dtype``
         func : callable
-            The callable that will be called to compute the format data. The
-            call signature of this function is simple, it must take the
-            object to be formatted and return the raw data for the given
-            format. Subclasses may use a different call signature for the
+            A callable for computing the format data.
+            `func` will be called with the object to be formatted,
+            and will return the raw data in this formatter's format.
+            Subclasses may use a different call signature for the
             `func` argument.
+            
+            If `func` is None or unspecified, there will be no change,
+            only returning the current value.
+        
+        Returns
+        -------
+        oldfunc : callable
+            The currently registered callable.
+            If you are registering a new formatter,
+            this will be the previous value (to enable restoring later).
         """
         key = (type_module, type_name)
-        oldfunc = self.deferred_printers.get(key, None)
+        
+        try:
+            oldfunc = self.lookup_by_type("%s.%s" % key)
+        except KeyError:
+            oldfunc = None
+        
         if func is not None:
-            # To support easy restoration of old printers, we need to ignore
-            # Nones.
             self.deferred_printers[key] = func
         return oldfunc
+    
+    def pop(self, typ, default=_raise_key_error):
+        """Pop a formatter for the given type.
+
+        Parameters
+        ----------
+        typ : type or '__module__.__name__' string for a type
+        default : object
+            value to be returned if no formatter is registered for typ.
+
+        Returns
+        -------
+        obj : object
+            The last registered object for the type.
+
+        Raises
+        ------
+        KeyError if the type is not registered and default is not specified.
+        """
+        
+        if isinstance(typ, string_types):
+            typ_key = tuple(typ.rsplit('.',1))
+            if typ_key not in self.deferred_printers:
+                # We may have it cached in the type map. We will have to
+                # iterate over all of the types to check.
+                for cls in self.type_printers:
+                    if _mod_name_key(cls) == typ_key:
+                        old = self.type_printers.pop(cls)
+                        break
+                else:
+                    old = default
+            else:
+                old = self.deferred_printers.pop(typ_key)
+        else:
+            if typ in self.type_printers:
+                old = self.type_printers.pop(typ)
+            else:
+                old = self.deferred_printers.pop(_mod_name_key(typ), default)
+        if old is _raise_key_error:
+            raise KeyError("No registered value for {0!r}".format(typ))
+        return old
 
     def _in_deferred_types(self, cls):
         """
         Check if the given class is specified in the deferred type registry.
 
-        Returns the printer from the registry if it exists, and None if the
-        class is not in the registry. Successful matches will be moved to the
-        regular type registry for future use.
+        Successful matches will be moved to the regular type registry for future use.
         """
         mod = getattr(cls, '__module__', None)
         name = getattr(cls, '__name__', None)
         key = (mod, name)
-        printer = None
         if key in self.deferred_printers:
             # Move the printer over to the regular registry.
             printer = self.deferred_printers.pop(key)
             self.type_printers[cls] = printer
-        return printer
+            return True
+        return False
 
 
 class PlainTextFormatter(BaseFormatter):
     """The default pretty-printer.
 
     This uses :mod:`IPython.lib.pretty` to compute the format data of
     the object. If the object cannot be pretty printed, :func:`repr` is used.
     See the documentation of :mod:`IPython.lib.pretty` for details on
     how to write pretty printers.  Here is a simple example::
 
         def dtype_pprinter(obj, p, cycle):
             if cycle:
                 return p.text('dtype(...)')
             if hasattr(obj, 'fields'):
                 if obj.fields is None:
                     p.text(repr(obj))
                 else:
                     p.begin_group(7, 'dtype([')
                     for i, field in enumerate(obj.descr):
                         if i > 0:
                             p.text(',')
                             p.breakable()
                         p.pretty(field)
                     p.end_group(7, '])')
     """
 
     # The format type of data returned.
     format_type = Unicode('text/plain')
 
     # This subclass ignores this attribute as it always need to return
     # something.
     enabled = Bool(True, config=False)
 
     # Look for a _repr_pretty_ methods to use for pretty printing.
     print_method = ObjectName('_repr_pretty_')
 
     # Whether to pretty-print or not.
     pprint = Bool(True, config=True)
 
     # Whether to be verbose or not.
     verbose = Bool(False, config=True)
 
     # The maximum width.
     max_width = Integer(79, config=True)
 
     # The newline character.
     newline = Unicode('\n', config=True)
 
     # format-string for pprinting floats
     float_format = Unicode('%r')
     # setter for float precision, either int or direct format-string
     float_precision = CUnicode('', config=True)
 
     def _float_precision_changed(self, name, old, new):
         """float_precision changed, set float_format accordingly.
 
         float_precision can be set by int or str.
         This will set float_format, after interpreting input.
         If numpy has been imported, numpy print precision will also be set.
 
         integer `n` sets format to '%.nf', otherwise, format set directly.
 
         An empty string returns to defaults (repr for float, 8 for numpy).
 
         This parameter can be set via the '%precision' magic.
         """
 
         if '%' in new:
             # got explicit format string
             fmt = new
             try:
                 fmt%3.14159
             except Exception:
                 raise ValueError("Precision must be int or format string, not %r"%new)
         elif new:
             # otherwise, should be an int
             try:
                 i = int(new)
                 assert i >= 0
             except ValueError:
                 raise ValueError("Precision must be int or format string, not %r"%new)
             except AssertionError:
                 raise ValueError("int precision must be non-negative, not %r"%i)
 
             fmt = '%%.%if'%i
             if 'numpy' in sys.modules:
                 # set numpy precision if it has been imported
                 import numpy
                 numpy.set_printoptions(precision=i)
         else:
             # default back to repr
             fmt = '%r'
             if 'numpy' in sys.modules:
                 import numpy
                 # numpy default is 8
                 numpy.set_printoptions(precision=8)
         self.float_format = fmt
 
     # Use the default pretty printers from IPython.lib.pretty.
     def _singleton_printers_default(self):
         return pretty._singleton_pprinters.copy()
 
     def _type_printers_default(self):
         d = pretty._type_pprinters.copy()
         d[float] = lambda obj,p,cycle: p.text(self.float_format%obj)
         return d
 
     def _deferred_printers_default(self):
         return pretty._deferred_type_pprinters.copy()
 
     #### FormatterABC interface ####
 
     def __call__(self, obj):
         """Compute the pretty representation of the object."""
         if not self.pprint:
             return pretty._safe_repr(obj)
         else:
             # This uses use StringIO, as cStringIO doesn't handle unicode.
             stream = StringIO()
             # self.newline.encode() is a quick fix for issue gh-597. We need to
             # ensure that stream does not get a mix of unicode and bytestrings,
             # or it will cause trouble.
             printer = pretty.RepresentationPrinter(stream, self.verbose,
                 self.max_width, unicode_to_str(self.newline),
                 singleton_pprinters=self.singleton_printers,
                 type_pprinters=self.type_printers,
                 deferred_pprinters=self.deferred_printers)
             printer.pretty(obj)
             printer.flush()
             return stream.getvalue()
 
 
 class HTMLFormatter(BaseFormatter):
     """An HTML formatter.
 
     To define the callables that compute the HTML representation of your
     objects, define a :meth:`_repr_html_` method or use the :meth:`for_type`
     or :meth:`for_type_by_name` methods to register functions that handle
     this.
 
     The return value of this formatter should be a valid HTML snippet that
     could be injected into an existing DOM. It should *not* include the
     ```<html>`` or ```<body>`` tags.
     """
     format_type = Unicode('text/html')
 
     print_method = ObjectName('_repr_html_')
 
 
 class SVGFormatter(BaseFormatter):
     """An SVG formatter.
 
     To define the callables that compute the SVG representation of your
     objects, define a :meth:`_repr_svg_` method or use the :meth:`for_type`
     or :meth:`for_type_by_name` methods to register functions that handle
     this.
 
     The return value of this formatter should be valid SVG enclosed in
     ```<svg>``` tags, that could be injected into an existing DOM. It should
     *not* include the ```<html>`` or ```<body>`` tags.
     """
     format_type = Unicode('image/svg+xml')
 
     print_method = ObjectName('_repr_svg_')
 
 
 class PNGFormatter(BaseFormatter):
     """A PNG formatter.
 
     To define the callables that compute the PNG representation of your
     objects, define a :meth:`_repr_png_` method or use the :meth:`for_type`
     or :meth:`for_type_by_name` methods to register functions that handle
     this.
 
     The return value of this formatter should be raw PNG data, *not*
     base64 encoded.
     """
     format_type = Unicode('image/png')
 
     print_method = ObjectName('_repr_png_')
 
 
 class JPEGFormatter(BaseFormatter):
     """A JPEG formatter.
 
     To define the callables that compute the JPEG representation of your
     objects, define a :meth:`_repr_jpeg_` method or use the :meth:`for_type`
     or :meth:`for_type_by_name` methods to register functions that handle
     this.
 
     The return value of this formatter should be raw JPEG data, *not*
     base64 encoded.
     """
     format_type = Unicode('image/jpeg')
 
     print_method = ObjectName('_repr_jpeg_')
 
 
 class LatexFormatter(BaseFormatter):
     """A LaTeX formatter.
 
     To define the callables that compute the LaTeX representation of your
     objects, define a :meth:`_repr_latex_` method or use the :meth:`for_type`
     or :meth:`for_type_by_name` methods to register functions that handle
     this.
 
     The return value of this formatter should be a valid LaTeX equation,
     enclosed in either ```$```, ```$$``` or another LaTeX equation
     environment.
     """
     format_type = Unicode('text/latex')
 
     print_method = ObjectName('_repr_latex_')
 
 
 class JSONFormatter(BaseFormatter):
     """A JSON string formatter.
 
     To define the callables that compute the JSON string representation of
     your objects, define a :meth:`_repr_json_` method or use the :meth:`for_type`
     or :meth:`for_type_by_name` methods to register functions that handle
     this.
 
     The return value of this formatter should be a valid JSON string.
     """
     format_type = Unicode('application/json')
 
     print_method = ObjectName('_repr_json_')
 
 
 class JavascriptFormatter(BaseFormatter):
     """A Javascript formatter.
 
     To define the callables that compute the Javascript representation of
     your objects, define a :meth:`_repr_javascript_` method or use the
     :meth:`for_type` or :meth:`for_type_by_name` methods to register functions
     that handle this.
 
     The return value of this formatter should be valid Javascript code and
     should *not* be enclosed in ```<script>``` tags.
     """
     format_type = Unicode('application/javascript')
 
     print_method = ObjectName('_repr_javascript_')
 
 FormatterABC.register(BaseFormatter)
 FormatterABC.register(PlainTextFormatter)
 FormatterABC.register(HTMLFormatter)
 FormatterABC.register(SVGFormatter)
 FormatterABC.register(PNGFormatter)
 FormatterABC.register(JPEGFormatter)
 FormatterABC.register(LatexFormatter)
 FormatterABC.register(JSONFormatter)
 FormatterABC.register(JavascriptFormatter)
 
 
 def format_display_data(obj, include=None, exclude=None):
     """Return a format data dict for an object.
 
     By default all format types will be computed.
 
     The following MIME types are currently implemented:
 
     * text/plain
     * text/html
     * text/latex
     * application/json
     * application/javascript
     * image/png
     * image/jpeg
     * image/svg+xml
 
     Parameters
     ----------
     obj : object
         The Python object whose format data will be computed.
 
     Returns
     -------
     format_dict : dict
         A dictionary of key/value pairs, one or each format that was
         generated for the object. The keys are the format types, which
         will usually be MIME type strings and the values and JSON'able
         data structure containing the raw data for the representation in
         that format.
     include : list or tuple, optional
         A list of format type strings (MIME types) to include in the
         format data dict. If this is set *only* the format types included
         in this list will be computed.
     exclude : list or tuple, optional
         A list of format type string (MIME types) to exclue in the format
         data dict. If this is set all format types will be computed,
         except for those included in this argument.
     """
     from IPython.core.interactiveshell import InteractiveShell
 
     InteractiveShell.instance().display_formatter.format(
         obj,
         include,
         exclude
     )
 

IPython/core/pylabtools.py

@@ -1,342 +1,342 b''
 # -*- coding: utf-8 -*-
 """Pylab (matplotlib) support utilities.
 
 Authors
 -------
 
 * Fernando Perez.
 * Brian Granger
 """
 from __future__ import print_function
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 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.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import sys
 from io import BytesIO
 
 from IPython.core.display import _pngxy
 from IPython.utils.decorators import flag_calls
 
 # If user specifies a GUI, that dictates the backend, otherwise we read the
 # user's mpl default from the mpl rc structure
 backends = {'tk': 'TkAgg',
             'gtk': 'GTKAgg',
             'gtk3': 'GTK3Agg',
             'wx': 'WXAgg',
             'qt': 'Qt4Agg', # qt3 not supported
             'qt4': 'Qt4Agg',
             'osx': 'MacOSX',
             'inline' : 'module://IPython.kernel.zmq.pylab.backend_inline'}
 
 # We also need a reverse backends2guis mapping that will properly choose which
 # GUI support to activate based on the desired matplotlib backend.  For the
 # most part it's just a reverse of the above dict, but we also need to add a
 # few others that map to the same GUI manually:
 backend2gui = dict(zip(backends.values(), backends.keys()))
 # Our tests expect backend2gui to just return 'qt'
 backend2gui['Qt4Agg'] = 'qt'
 # In the reverse mapping, there are a few extra valid matplotlib backends that
 # map to the same GUI support
 backend2gui['GTK'] = backend2gui['GTKCairo'] = 'gtk'
 backend2gui['GTK3Cairo'] = 'gtk3'
 backend2gui['WX'] = 'wx'
 backend2gui['CocoaAgg'] = 'osx'
 
 #-----------------------------------------------------------------------------
 # Matplotlib utilities
 #-----------------------------------------------------------------------------
 
 
 def getfigs(*fig_nums):
     """Get a list of matplotlib figures by figure numbers.
 
     If no arguments are given, all available figures are returned.  If the
     argument list contains references to invalid figures, a warning is printed
     but the function continues pasting further figures.
 
     Parameters
     ----------
     figs : tuple
         A tuple of ints giving the figure numbers of the figures to return.
     """
     from matplotlib._pylab_helpers import Gcf
     if not fig_nums:
         fig_managers = Gcf.get_all_fig_managers()
         return [fm.canvas.figure for fm in fig_managers]
     else:
         figs = []
         for num in fig_nums:
             f = Gcf.figs.get(num)
             if f is None:
                 print('Warning: figure %s not available.' % num)
             else:
                 figs.append(f.canvas.figure)
         return figs
 
 
 def figsize(sizex, sizey):
     """Set the default figure size to be [sizex, sizey].
 
     This is just an easy to remember, convenience wrapper that sets::
 
       matplotlib.rcParams['figure.figsize'] = [sizex, sizey]
     """
     import matplotlib
     matplotlib.rcParams['figure.figsize'] = [sizex, sizey]
 
 
 def print_figure(fig, fmt='png'):
     """Convert a figure to svg or png for inline display."""
     from matplotlib import rcParams
     # When there's an empty figure, we shouldn't return anything, otherwise we
     # get big blank areas in the qt console.
     if not fig.axes and not fig.lines:
         return
 
     fc = fig.get_facecolor()
     ec = fig.get_edgecolor()
     bytes_io = BytesIO()
     dpi = rcParams['savefig.dpi']
     if fmt == 'retina':
         dpi = dpi * 2
         fmt = 'png'
     fig.canvas.print_figure(bytes_io, format=fmt, bbox_inches='tight',
                             facecolor=fc, edgecolor=ec, dpi=dpi)
     data = bytes_io.getvalue()
     return data
     
 def retina_figure(fig):
     """format a figure as a pixel-doubled (retina) PNG"""
     pngdata = print_figure(fig, fmt='retina')
     w, h = _pngxy(pngdata)
     metadata = dict(width=w//2, height=h//2)
     return pngdata, metadata
 
 # We need a little factory function here to create the closure where
 # safe_execfile can live.
 def mpl_runner(safe_execfile):
     """Factory to return a matplotlib-enabled runner for %run.
 
     Parameters
     ----------
     safe_execfile : function
       This must be a function with the same interface as the
       :meth:`safe_execfile` method of IPython.
 
     Returns
     -------
     A function suitable for use as the ``runner`` argument of the %run magic
     function.
     """
     
     def mpl_execfile(fname,*where,**kw):
         """matplotlib-aware wrapper around safe_execfile.
 
         Its interface is identical to that of the :func:`execfile` builtin.
 
         This is ultimately a call to execfile(), but wrapped in safeties to
         properly handle interactive rendering."""
 
         import matplotlib
         import matplotlib.pylab as pylab
 
         #print '*** Matplotlib runner ***' # dbg
         # turn off rendering until end of script
         is_interactive = matplotlib.rcParams['interactive']
         matplotlib.interactive(False)
         safe_execfile(fname,*where,**kw)
         matplotlib.interactive(is_interactive)
         # make rendering call now, if the user tried to do it
         if pylab.draw_if_interactive.called:
             pylab.draw()
             pylab.draw_if_interactive.called = False
 
     return mpl_execfile
 
 
 def select_figure_format(shell, fmt):
     """Select figure format for inline backend, can be 'png', 'retina', or 'svg'.
 
     Using this method ensures only one figure format is active at a time.
     """
     from matplotlib.figure import Figure
     from IPython.kernel.zmq.pylab import backend_inline
 
     svg_formatter = shell.display_formatter.formatters['image/svg+xml']
     png_formatter = shell.display_formatter.formatters['image/png']
 
     if fmt == 'png':
-        svg_formatter.type_printers.pop(Figure, None)
+        svg_formatter.pop(Figure, None)
         png_formatter.for_type(Figure, lambda fig: print_figure(fig, 'png'))
     elif fmt in ('png2x', 'retina'):
-        svg_formatter.type_printers.pop(Figure, None)
+        svg_formatter.pop(Figure, None)
         png_formatter.for_type(Figure, retina_figure)
     elif fmt == 'svg':
-        png_formatter.type_printers.pop(Figure, None)
+        png_formatter.pop(Figure, None)
         svg_formatter.for_type(Figure, lambda fig: print_figure(fig, 'svg'))
     else:
         raise ValueError("supported formats are: 'png', 'retina', 'svg', not %r" % fmt)
 
     # set the format to be used in the backend()
     backend_inline._figure_format = fmt
 
 #-----------------------------------------------------------------------------
 # Code for initializing matplotlib and importing pylab
 #-----------------------------------------------------------------------------
 
 
 def find_gui_and_backend(gui=None, gui_select=None):
     """Given a gui string return the gui and mpl backend.
 
     Parameters
     ----------
     gui : str
         Can be one of ('tk','gtk','wx','qt','qt4','inline').
     gui_select : str
         Can be one of ('tk','gtk','wx','qt','qt4','inline').
         This is any gui already selected by the shell.
 
     Returns
     -------
     A tuple of (gui, backend) where backend is one of ('TkAgg','GTKAgg',
     'WXAgg','Qt4Agg','module://IPython.kernel.zmq.pylab.backend_inline').
     """
 
     import matplotlib
 
     if gui and gui != 'auto':
         # select backend based on requested gui
         backend = backends[gui]
     else:
         # We need to read the backend from the original data structure, *not*
         # from mpl.rcParams, since a prior invocation of %matplotlib may have
         # overwritten that.
         # WARNING: this assumes matplotlib 1.1 or newer!!
         backend = matplotlib.rcParamsOrig['backend']
         # In this case, we need to find what the appropriate gui selection call
         # should be for IPython, so we can activate inputhook accordingly
         gui = backend2gui.get(backend, None)
 
         # If we have already had a gui active, we need it and inline are the
         # ones allowed.
         if gui_select and gui != gui_select:
             gui = gui_select
             backend = backends[gui]
 
     return gui, backend
 
 
 def activate_matplotlib(backend):
     """Activate the given backend and set interactive to True."""
 
     import matplotlib
     matplotlib.interactive(True)
     
     # Matplotlib had a bug where even switch_backend could not force
     # the rcParam to update. This needs to be set *before* the module
     # magic of switch_backend().
     matplotlib.rcParams['backend'] = backend
 
     import matplotlib.pyplot
     matplotlib.pyplot.switch_backend(backend)
 
     # This must be imported last in the matplotlib series, after
     # backend/interactivity choices have been made
     import matplotlib.pylab as pylab
 
     pylab.show._needmain = False
     # We need to detect at runtime whether show() is called by the user.
     # For this, we wrap it into a decorator which adds a 'called' flag.
     pylab.draw_if_interactive = flag_calls(pylab.draw_if_interactive)
 
 
 def import_pylab(user_ns, import_all=True):
     """Populate the namespace with pylab-related values.
     
     Imports matplotlib, pylab, numpy, and everything from pylab and numpy.
     
     Also imports a few names from IPython (figsize, display, getfigs)
     
     """
 
     # 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.
     s = ("import numpy\n"
           "import matplotlib\n"
           "from matplotlib import pylab, mlab, pyplot\n"
           "np = numpy\n"
           "plt = pyplot\n"
           )
     exec(s, user_ns)
     
     if import_all:
         s = ("from matplotlib.pylab import *\n"
              "from numpy import *\n")
         exec(s, user_ns)
     
     # IPython symbols to add
     user_ns['figsize'] = figsize
     from IPython.core.display import display
     # Add display and getfigs to the user's namespace
     user_ns['display'] = display
     user_ns['getfigs'] = getfigs
 
 
 def configure_inline_support(shell, backend):
     """Configure an IPython shell object for matplotlib use.
 
     Parameters
     ----------
     shell : InteractiveShell instance
 
     backend : matplotlib backend
     """
     # If using our svg payload backend, register the post-execution
     # function that will pick up the results for display.  This can only be
     # done with access to the real shell object.
 
     # Note: if we can't load the inline backend, then there's no point
     # continuing (such as in terminal-only shells in environments without
     # zeromq available).
     try:
         from IPython.kernel.zmq.pylab.backend_inline import InlineBackend
     except ImportError:
         return
     from matplotlib import pyplot
 
     cfg = InlineBackend.instance(parent=shell)
     cfg.shell = shell
     if cfg not in shell.configurables:
         shell.configurables.append(cfg)
 
     if backend == backends['inline']:
         from IPython.kernel.zmq.pylab.backend_inline import flush_figures
         shell.register_post_execute(flush_figures)
 
         # Save rcParams that will be overwrittern
         shell._saved_rcParams = dict()
         for k in cfg.rc:
             shell._saved_rcParams[k] = pyplot.rcParams[k]
         # load inline_rc
         pyplot.rcParams.update(cfg.rc)
     else:
         from IPython.kernel.zmq.pylab.backend_inline import flush_figures
         if flush_figures in shell._post_execute:
             shell._post_execute.pop(flush_figures)
         if hasattr(shell, '_saved_rcParams'):
             pyplot.rcParams.update(shell._saved_rcParams)
             del shell._saved_rcParams
 
     # Setup the default figure format
     select_figure_format(shell, cfg.figure_format)
 

IPython/core/tests/test_formatters.py

@@ -1,90 +1,234 b''
 """Tests for the Formatters.
 """
 
 from math import pi
 
 try:
     import numpy
 except:
     numpy = None
 import nose.tools as nt
 
-from IPython.core.formatters import PlainTextFormatter
+from IPython.core.formatters import PlainTextFormatter, _mod_name_key
 
 class A(object):
     def __repr__(self):
         return 'A()'
 
 class B(A):
     def __repr__(self):
         return 'B()'
 
+class C:
+    pass
+
 class BadPretty(object):
     _repr_pretty_ = None
 
 class GoodPretty(object):
     def _repr_pretty_(self, pp, cycle):
         pp.text('foo')
 
     def __repr__(self):
         return 'GoodPretty()'
 
 def foo_printer(obj, pp, cycle):
     pp.text('foo')
 
 def test_pretty():
     f = PlainTextFormatter()
     f.for_type(A, foo_printer)
     nt.assert_equal(f(A()), 'foo')
     nt.assert_equal(f(B()), 'foo')
     nt.assert_equal(f(GoodPretty()), 'foo')
     # Just don't raise an exception for the following:
     f(BadPretty())
 
     f.pprint = False
     nt.assert_equal(f(A()), 'A()')
     nt.assert_equal(f(B()), 'B()')
     nt.assert_equal(f(GoodPretty()), 'GoodPretty()')
 
 
 def test_deferred():
     f = PlainTextFormatter()
 
 def test_precision():
     """test various values for float_precision."""
     f = PlainTextFormatter()
     nt.assert_equal(f(pi), repr(pi))
     f.float_precision = 0
     if numpy:
         po = numpy.get_printoptions()
         nt.assert_equal(po['precision'], 0)
     nt.assert_equal(f(pi), '3')
     f.float_precision = 2
     if numpy:
         po = numpy.get_printoptions()
         nt.assert_equal(po['precision'], 2)
     nt.assert_equal(f(pi), '3.14')
     f.float_precision = '%g'
     if numpy:
         po = numpy.get_printoptions()
         nt.assert_equal(po['precision'], 2)
     nt.assert_equal(f(pi), '3.14159')
     f.float_precision = '%e'
     nt.assert_equal(f(pi), '3.141593e+00')
     f.float_precision = ''
     if numpy:
         po = numpy.get_printoptions()
         nt.assert_equal(po['precision'], 8)
     nt.assert_equal(f(pi), repr(pi))
 
 def test_bad_precision():
     """test various invalid values for float_precision."""
     f = PlainTextFormatter()
     def set_fp(p):
         f.float_precision=p
     nt.assert_raises(ValueError, set_fp, '%')
     nt.assert_raises(ValueError, set_fp, '%.3f%i')
     nt.assert_raises(ValueError, set_fp, 'foo')
     nt.assert_raises(ValueError, set_fp, -1)
 
+def test_for_type():
+    f = PlainTextFormatter()
+    
+    # initial return, None
+    nt.assert_is(f.for_type(C, foo_printer), None)
+    # no func queries
+    nt.assert_is(f.for_type(C), foo_printer)
+    # shouldn't change anything
+    nt.assert_is(f.for_type(C), foo_printer)
+    # None should do the same
+    nt.assert_is(f.for_type(C, None), foo_printer)
+    nt.assert_is(f.for_type(C, None), foo_printer)
+
+def test_for_type_string():
+    f = PlainTextFormatter()
+    
+    mod = C.__module__
+    
+    type_str = '%s.%s' % (C.__module__, 'C')
+    
+    # initial return, None
+    nt.assert_is(f.for_type(type_str, foo_printer), None)
+    # no func queries
+    nt.assert_is(f.for_type(type_str), foo_printer)
+    nt.assert_in(_mod_name_key(C), f.deferred_printers)
+    nt.assert_is(f.for_type(C), foo_printer)
+    nt.assert_not_in(_mod_name_key(C), f.deferred_printers)
+    nt.assert_in(C, f.type_printers)
+
+def test_for_type_by_name():
+    f = PlainTextFormatter()
+    
+    mod = C.__module__
+    
+    # initial return, None
+    nt.assert_is(f.for_type_by_name(mod, 'C', foo_printer), None)
+    # no func queries
+    nt.assert_is(f.for_type_by_name(mod, 'C'), foo_printer)
+    # shouldn't change anything
+    nt.assert_is(f.for_type_by_name(mod, 'C'), foo_printer)
+    # None should do the same
+    nt.assert_is(f.for_type_by_name(mod, 'C', None), foo_printer)
+    nt.assert_is(f.for_type_by_name(mod, 'C', None), foo_printer)
+
+def test_lookup():
+    f = PlainTextFormatter()
+    
+    f.for_type(C, foo_printer)
+    nt.assert_is(f.lookup(C()), foo_printer)
+    with nt.assert_raises(KeyError):
+        f.lookup(A())
+
+def test_lookup_string():
+    f = PlainTextFormatter()
+    type_str = '%s.%s' % (C.__module__, 'C')
+    
+    f.for_type(type_str, foo_printer)
+    nt.assert_is(f.lookup(C()), foo_printer)
+    # should move from deferred to imported dict
+    nt.assert_not_in(_mod_name_key(C), f.deferred_printers)
+    nt.assert_in(C, f.type_printers)
+
+def test_lookup_by_type():
+    f = PlainTextFormatter()
+    f.for_type(C, foo_printer)
+    nt.assert_is(f.lookup_by_type(C), foo_printer)
+    type_str = '%s.%s' % (C.__module__, 'C')
+    with nt.assert_raises(KeyError):
+        f.lookup_by_type(A)
+
+def test_lookup_by_type_string():
+    f = PlainTextFormatter()
+    type_str = '%s.%s' % (C.__module__, 'C')
+    f.for_type(type_str, foo_printer)
+    
+    # verify insertion
+    nt.assert_in(_mod_name_key(C), f.deferred_printers)
+    nt.assert_not_in(C, f.type_printers)
+    
+    nt.assert_is(f.lookup_by_type(type_str), foo_printer)
+    # lookup by string doesn't cause import
+    nt.assert_in(_mod_name_key(C), f.deferred_printers)
+    nt.assert_not_in(C, f.type_printers)
+    
+    nt.assert_is(f.lookup_by_type(C), foo_printer)
+    # should move from deferred to imported dict
+    nt.assert_not_in(_mod_name_key(C), f.deferred_printers)
+    nt.assert_in(C, f.type_printers)
+
+def test_in_formatter():
+    f = PlainTextFormatter()
+    f.for_type(C, foo_printer)
+    type_str = '%s.%s' % (C.__module__, 'C')
+    nt.assert_in(C, f)
+    nt.assert_in(type_str, f)
+
+def test_string_in_formatter():
+    f = PlainTextFormatter()
+    type_str = '%s.%s' % (C.__module__, 'C')
+    f.for_type(type_str, foo_printer)
+    nt.assert_in(type_str, f)
+    nt.assert_in(C, f)
+
+def test_pop():
+    f = PlainTextFormatter()
+    f.for_type(C, foo_printer)
+    nt.assert_is(f.lookup_by_type(C), foo_printer)
+    nt.assert_is(f.pop(C, None), foo_printer)
+    f.for_type(C, foo_printer)
+    nt.assert_is(f.pop(C), foo_printer)
+    with nt.assert_raises(KeyError):
+        f.lookup_by_type(C)
+    with nt.assert_raises(KeyError):
+        f.pop(C)
+    with nt.assert_raises(KeyError):
+        f.pop(A)
+    nt.assert_is(f.pop(A, None), None)
+
+def test_pop_string():
+    f = PlainTextFormatter()
+    type_str = '%s.%s' % (C.__module__, 'C')
+    
+    with nt.assert_raises(KeyError):
+        f.pop(type_str)
+    
+    f.for_type(type_str, foo_printer)
+    f.pop(type_str)
+    with nt.assert_raises(KeyError):
+        f.lookup_by_type(C)
+    with nt.assert_raises(KeyError):
+        f.pop(type_str)
+
+    f.for_type(C, foo_printer)
+    nt.assert_is(f.pop(type_str, None), foo_printer)
+    with nt.assert_raises(KeyError):
+        f.lookup_by_type(C)
+    with nt.assert_raises(KeyError):
+        f.pop(type_str)
+    nt.assert_is(f.pop(type_str, None), None)
+    
+