Adding const pseudo-widget for fixing arguments to interact.

IPython/html/widgets/__init__.py

@@ -1,12 +1,12 b''
 from .widget import Widget, DOMWidget, CallbackDispatcher
 
 from .widget_bool import CheckboxWidget, ToggleButtonWidget
 from .widget_button import ButtonWidget
 from .widget_container import ContainerWidget, PopupWidget
 from .widget_float import FloatTextWidget, BoundedFloatTextWidget, FloatSliderWidget, FloatProgressWidget
 from .widget_image import ImageWidget
 from .widget_int import IntTextWidget, BoundedIntTextWidget, IntSliderWidget, IntProgressWidget
 from .widget_selection import RadioButtonsWidget, ToggleButtonsWidget, DropdownWidget, SelectWidget
 from .widget_selectioncontainer import TabWidget, AccordionWidget
 from .widget_string import HTMLWidget, LatexWidget, TextWidget, TextareaWidget
-from .interaction import interact, interactive, annotate
+from .interaction import interact, interactive, annotate, const

IPython/html/widgets/interaction.py

@@ -1,276 +1,286 b''
 """Interact with functions using widgets."""
 
 #-----------------------------------------------------------------------------
 # Copyright (c) 2013, the 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
 #-----------------------------------------------------------------------------
 
 from __future__ import print_function
 
 try:  # Python >= 3.3
     from inspect import signature, Parameter
 except ImportError:
     from IPython.utils.signatures import signature, Parameter
 from inspect import getcallargs
 
 from IPython.html.widgets import (Widget, TextWidget,
     FloatSliderWidget, IntSliderWidget, CheckboxWidget, DropdownWidget,
-    ContainerWidget)
+    ContainerWidget, DOMWidget)
 from IPython.display import display, clear_output
 from IPython.utils.py3compat import string_types, unicode_type
+from IPython.utils.traitlets import HasTraits, Any, Unicode
 
 #-----------------------------------------------------------------------------
 # Classes and Functions
 #-----------------------------------------------------------------------------
 
 
 def _matches(o, pattern):
     """Match a pattern of types in a sequence."""
     if not len(o) == len(pattern):
         return False
     comps = zip(o,pattern)
     return all(isinstance(obj,kind) for obj,kind in comps)
 
 
 def _get_min_max_value(min, max, value):
     """Return min, max, value given input values with possible None."""
     if value is None:
         if not max > min:
             raise ValueError('max must be greater than min: (min={0}, max={1})'.format(min, max))
         value = min + abs(min-max)/2
         value = type(min)(value)
     elif min is None and max is None:
         if value == 0.0:
             min, max, value = 0.0, 1.0, 0.5
         elif value == 0:
             min, max, value = 0, 1, 0
         elif isinstance(value, float):
             min, max = (-value, 3.0*value) if value > 0 else (3.0*value, -value)
         elif isinstance(value, int):
             min, max = (-value, 3*value) if value > 0 else (3*value, -value)
         else:
             raise TypeError('expected a number, got: %r' % value)
     else:
         raise ValueError('unable to infer range, value from: ({0}, {1}, {2})'.format(min, max, value))
     return min, max, value
 
 def _widget_abbrev_single_value(o):
     """Make widgets from single values, which can be used written as parameter defaults."""
     if isinstance(o, string_types):
         return TextWidget(value=unicode_type(o))
     elif isinstance(o, dict):
         labels = [unicode_type(k) for k in o]
         values = o.values()
         w = DropdownWidget(value=values[0], values=values, labels=labels)
         return w
     elif isinstance(o, bool):
         return CheckboxWidget(value=o)
     elif isinstance(o, float):
         min, max, value = _get_min_max_value(None, None, o)
         return FloatSliderWidget(value=o, min=min, max=max)
     elif isinstance(o, int):
         min, max, value = _get_min_max_value(None, None, o)
         return IntSliderWidget(value=o, min=min, max=max)
     else:
         return None
 
 def _widget_abbrev(o):
     """Make widgets from abbreviations: single values, lists or tuples."""
     if isinstance(o, (list, tuple)):
         if _matches(o, (int, int)):
             min, max, value = _get_min_max_value(o[0], o[1], None)
             return IntSliderWidget(value=value, min=min, max=max)
         elif _matches(o, (int, int, int)):
             min, max, value = _get_min_max_value(o[0], o[1], None)
             return IntSliderWidget(value=value, min=min, max=max, step=o[2])
         elif _matches(o, (float, float)):
             min, max, value = _get_min_max_value(o[0], o[1], None)
             return FloatSliderWidget(value=value, min=min, max=max)
         elif _matches(o, (float, float, float)):
             min, max, value = _get_min_max_value(o[0], o[1], None)
             return FloatSliderWidget(value=value, min=min, max=max, step=o[2])
         elif _matches(o, (float, float, int)):
             min, max, value = _get_min_max_value(o[0], o[1], None)
             return FloatSliderWidget(value=value, min=min, max=max, step=float(o[2]))
         elif all(isinstance(x, string_types) for x in o):
             return DropdownWidget(value=unicode_type(o[0]),
                                    values=[unicode_type(k) for k in o])
     else:
         return _widget_abbrev_single_value(o)
 
 def _widget_from_abbrev(abbrev):
     """Build a Widget intstance given an abbreviation or Widget."""
-    if isinstance(abbrev, Widget):
+    if isinstance(abbrev, Widget) or isinstance(abbrev, const):
         return abbrev
     
     widget = _widget_abbrev(abbrev)
     if widget is None:
         raise ValueError("%r cannot be transformed to a Widget" % abbrev)
     return widget
 
 def _yield_abbreviations_for_parameter(param, args, kwargs):
     """Get an abbreviation for a function parameter."""
     # print(param, args, kwargs)
     name = param.name
     kind = param.kind
     ann = param.annotation
     default = param.default
     empty = Parameter.empty
     if kind == Parameter.POSITIONAL_ONLY:
         if args:
             yield name, args.pop(0), False
         elif ann is not empty:
             yield name, ann, False
         else:
             yield None, None, None
     elif kind == Parameter.POSITIONAL_OR_KEYWORD:
         if name in kwargs:
             yield name, kwargs.pop(name), True
         elif args:
             yield name, args.pop(0), False
         elif ann is not empty:
             if default is empty:
                 yield name, ann, False
             else:
                 yield name, ann, True
         elif default is not empty:
             yield name, default, True
         else:
             yield None, None, None
     elif kind == Parameter.VAR_POSITIONAL:
         # In this case name=args or something and we don't actually know the names.
         for item in args[::]:
             args.pop(0)
             yield '', item, False
     elif kind == Parameter.KEYWORD_ONLY:
         if name in kwargs:
             yield name, kwargs.pop(name), True
         elif ann is not empty:
             yield name, ann, True
         elif default is not empty:
             yield name, default, True
         else:
             yield None, None, None
     elif kind == Parameter.VAR_KEYWORD:
         # In this case name=kwargs and we yield the items in kwargs with their keys.
         for k, v in kwargs.copy().items():
             kwargs.pop(k)
             yield k, v, True
 
 def _find_abbreviations(f, args, kwargs):
     """Find the abbreviations for a function and args/kwargs passed to interact."""
     new_args = []
     new_kwargs = []
     for param in signature(f).parameters.values():
         for name, value, kw in _yield_abbreviations_for_parameter(param, args, kwargs):
             if value is None:
                 raise ValueError('cannot find widget or abbreviation for argument: {!r}'.format(name))
             if kw:
                 new_kwargs.append((name, value))
             else:
                 new_args.append((name, value))
     return new_args, new_kwargs
 
 def _widgets_from_abbreviations(seq):
     """Given a sequence of (name, abbrev) tuples, return a sequence of Widgets."""
     result = []
     for name, abbrev in seq:
         widget = _widget_from_abbrev(abbrev)
         widget.description = name
         result.append(widget)
     return result
 
 def interactive(f, *args, **kwargs):
     """Build a group of widgets to interact with a function."""
     co = kwargs.pop('clear_output', True)
     args_widgets = []
     kwargs_widgets = []
     container = ContainerWidget()
     container.result = None
     container.args = []
     container.kwargs = dict()
     # We need this to be a list as we iteratively pop elements off it
     args = list(args)
     kwargs = kwargs.copy()
 
     new_args, new_kwargs = _find_abbreviations(f, args, kwargs)
     # Before we proceed, let's make sure that the user has passed a set of args+kwargs
     # that will lead to a valid call of the function. This protects against unspecified
     # and doubly-specified arguments.
     getcallargs(f, *[v for n,v in new_args], **{n:v for n,v in new_kwargs})
     # Now build the widgets from the abbreviations.
     args_widgets.extend(_widgets_from_abbreviations(new_args))
     kwargs_widgets.extend(_widgets_from_abbreviations(new_kwargs))
     kwargs_widgets.extend(_widgets_from_abbreviations(sorted(kwargs.items(), key = lambda x: x[0])))
 
     # This has to be done as an assignment, not using container.children.append,
-    # so that traitlets notices the update.
-    container.children = args_widgets + kwargs_widgets
+    # so that traitlets notices the update. We skip any objects (such as const) that
+    # are not DOMWidgets.
+    c = [w for w in args_widgets+kwargs_widgets if isinstance(w, DOMWidget)]
+    container.children = c
 
     # Build the callback
     def call_f(name, old, new):
         container.args = []
         for widget in args_widgets:
             value = widget.value
             container.args.append(value)
         for widget in kwargs_widgets:
             value = widget.value
             container.kwargs[widget.description] = value
         if co:
             clear_output(wait=True)
         container.result = f(*container.args, **container.kwargs)
 
     # Wire up the widgets
     for widget in args_widgets:
         widget.on_trait_change(call_f, 'value')
     for widget in kwargs_widgets:
         widget.on_trait_change(call_f, 'value')
 
     container.on_displayed(lambda _: call_f(None, None, None))
 
     return container
 
 def interact(*args, **kwargs):
     """Interact with a function using widgets."""
     if args and callable(args[0]):
         # This branch handles the cases:
         # 1. interact(f, *args, **kwargs)
         # 2. @interact
         #    def f(*args, **kwargs):
         #        ...
         f = args[0]
         w = interactive(f, *args[1:], **kwargs)
         f.widget = w
         display(w)
     else:
         # This branch handles the case:
         # @interact(10, 20, a=30, b=40)
         # def f(*args, **kwargs):
         #     ...
         def dec(f):
             w = interactive(f, *args, **kwargs)
             f.widget = w
             display(w)
             return f
         return dec
 
+class const(HasTraits):
+    """A pseudo-widget whose value is constant and never client synced."""
+    value = Any(help="Any Python object")
+    description = Unicode('', help="Any Python object")
+    def __init__(self, value, **kwargs):
+        super(const, self).__init__(value=value, **kwargs)
+
 def annotate(**kwargs):
     """Python 3 compatible function annotation for Python 2."""
     if not kwargs:
         raise ValueError('annotations must be provided as keyword arguments')
     def dec(f):
         if hasattr(f, '__annotations__'):
             for k, v in kwargs.items():
                 f.__annotations__[k] = v
         else:
             f.__annotations__ = kwargs
         return f
     return dec