##// END OF EJS Templates
Document that _repr_*_() can return metadata
Zi Chong Kao -
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@@ -1,88 +1,95
1 .. _integrating:
1 .. _integrating:
2
2
3 =====================================
3 =====================================
4 Integrating your objects with IPython
4 Integrating your objects with IPython
5 =====================================
5 =====================================
6
6
7 Tab completion
7 Tab completion
8 ==============
8 ==============
9
9
10 To change the attributes displayed by tab-completing your object, define a
10 To change the attributes displayed by tab-completing your object, define a
11 ``__dir__(self)`` method for it. For more details, see the documentation of the
11 ``__dir__(self)`` method for it. For more details, see the documentation of the
12 built-in `dir() function <http://docs.python.org/library/functions.html#dir>`_.
12 built-in `dir() function <http://docs.python.org/library/functions.html#dir>`_.
13
13
14 You can also customise key completions for your objects, e.g. pressing tab after
14 You can also customise key completions for your objects, e.g. pressing tab after
15 ``obj["a``. To do so, define a method ``_ipython_key_completions_()``, which
15 ``obj["a``. To do so, define a method ``_ipython_key_completions_()``, which
16 returns a list of objects which are possible keys in a subscript expression
16 returns a list of objects which are possible keys in a subscript expression
17 ``obj[key]``.
17 ``obj[key]``.
18
18
19 .. versionadded:: 5.0
19 .. versionadded:: 5.0
20 Custom key completions
20 Custom key completions
21
21
22 .. _integrating_rich_display:
22 .. _integrating_rich_display:
23
23
24 Rich display
24 Rich display
25 ============
25 ============
26
26
27 The notebook and the Qt console can display richer representations of objects.
27 The notebook and the Qt console can display richer representations of objects.
28 To use this, you can define any of a number of ``_repr_*_()`` methods. Note that
28 To use this, you can define any number of ``_repr_*_()`` methods. Note that
29 these are surrounded by single, not double underscores.
29 these are surrounded by single, not double underscores.
30
30
31 Both the notebook and the Qt console can display ``svg``, ``png`` and ``jpeg``
31 Both the notebook and the Qt console can display ``svg``, ``png`` and ``jpeg``
32 representations. The notebook can also display ``html``, ``javascript``,
32 representations. The notebook can also display ``html``, ``javascript``,
33 ``markdown`` and ``latex``. If the methods don't exist, or return ``None``, it
33 ``markdown`` and ``latex``. If the methods don't exist, or return ``None``, it
34 falls back to a standard ``repr()``.
34 falls back to a standard ``repr()``.
35
35
36 For example::
36 For example::
37
37
38 class Shout(object):
38 class Shout(object):
39 def __init__(self, text):
39 def __init__(self, text):
40 self.text = text
40 self.text = text
41
41
42 def _repr_html_(self):
42 def _repr_html_(self):
43 return "<h1>" + self.text + "</h1>"
43 return "<h1>" + self.text + "</h1>"
44
44
45 We often want to provide frontends with guidance on how to display the data. To
46 support this, ``_repr_*_()`` methods can also return a data, metadata tuple where
47 metadata is a dictionary containing arbitrary key, value pairs for the frontend
48 to interpret. An example use case is ``_repr_jpeg()``, which can be set to
49 return a jpeg image and a ``{'height': 400, 'width': 600}`` dictionary to inform
50 the frontend how to size the image.
51
45 There are also two more powerful display methods:
52 There are also two more powerful display methods:
46
53
47 .. class:: MyObject
54 .. class:: MyObject
48
55
49 .. method:: _repr_mimebundle_(include=None, exclude=None)
56 .. method:: _repr_mimebundle_(include=None, exclude=None)
50
57
51 Should return a dictionary of multiple formats, keyed by mimetype, or a tuple
58 Should return a dictionary of multiple formats, keyed by mimetype, or a tuple
52 of two dictionaries: *data, metadata*. If this returns something, other
59 of two dictionaries: *data, metadata*. If this returns something, other
53 ``_repr_*_`` methods are ignored. The method should take keyword arguments
60 ``_repr_*_`` methods are ignored. The method should take keyword arguments
54 ``include`` and ``exclude``, though it is not required to respect them.
61 ``include`` and ``exclude``, though it is not required to respect them.
55
62
56 .. method:: _ipython_display_()
63 .. method:: _ipython_display_()
57
64
58 Displays the object as a side effect; the return value is ignored. If this
65 Displays the object as a side effect; the return value is ignored. If this
59 is defined, all other display methods are ignored.
66 is defined, all other display methods are ignored.
60
67
61 Formatters for third-party types
68 Formatters for third-party types
62 --------------------------------
69 --------------------------------
63
70
64 The user can also register formatters for types without modifying the class::
71 The user can also register formatters for types without modifying the class::
65
72
66 from bar import Foo
73 from bar import Foo
67
74
68 def foo_html(obj):
75 def foo_html(obj):
69 return '<marquee>Foo object %s</marquee>' % obj.name
76 return '<marquee>Foo object %s</marquee>' % obj.name
70
77
71 html_formatter = get_ipython().display_formatter.formatters['text/html']
78 html_formatter = get_ipython().display_formatter.formatters['text/html']
72 html_formatter.for_type(Foo, foo_html)
79 html_formatter.for_type(Foo, foo_html)
73
80
74 # Or register a type without importing it - this does the same as above:
81 # Or register a type without importing it - this does the same as above:
75 html_formatter.for_type_by_name('bar.Foo', foo_html)
82 html_formatter.for_type_by_name('bar.Foo', foo_html)
76
83
77 Custom exception tracebacks
84 Custom exception tracebacks
78 ===========================
85 ===========================
79
86
80 Rarely, you might want to display a custom traceback when reporting an
87 Rarely, you might want to display a custom traceback when reporting an
81 exception. To do this, define the custom traceback using
88 exception. To do this, define the custom traceback using
82 `_render_traceback_(self)` method which returns a list of strings, one string
89 `_render_traceback_(self)` method which returns a list of strings, one string
83 for each line of the traceback. For example, the `ipyparallel
90 for each line of the traceback. For example, the `ipyparallel
84 <http://ipyparallel.readthedocs.io/>`__ a parallel computing framework for
91 <http://ipyparallel.readthedocs.io/>`__ a parallel computing framework for
85 IPython, does this to display errors from multiple engines.
92 IPython, does this to display errors from multiple engines.
86
93
87 Please be conservative in using this feature; by replacing the default traceback
94 Please be conservative in using this feature; by replacing the default traceback
88 you may hide important information from the user.
95 you may hide important information from the user.
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