"""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.core.getipython import get_ipython from IPython.html.widgets import (Widget, TextWidget, FloatSliderWidget, IntSliderWidget, CheckboxWidget, DropdownWidget, 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=None, step=None): """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, (int, float)): 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)) if step is not None: # ensure value is on a step r = (value - min) % step value = value - r return min, max, value def _widget_abbrev_single_value(o): """Make widgets from single values, which can be used as parameter defaults.""" if isinstance(o, string_types): return TextWidget(value=unicode_type(o)) elif isinstance(o, dict): return DropdownWidget(values=o) 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.""" float_or_int = (float, int) if isinstance(o, (list, tuple)): if o and all(isinstance(x, string_types) for x in o): return DropdownWidget(values=[unicode_type(k) for k in o]) elif _matches(o, (float_or_int, float_or_int)): min, max, value = _get_min_max_value(o[0], o[1]) if all(isinstance(_, int) for _ in o): cls = IntSliderWidget else: cls = FloatSliderWidget return cls(value=value, min=min, max=max) elif _matches(o, (float_or_int, float_or_int, float_or_int)): step = o[2] if step <= 0: raise ValueError("step must be >= 0, not %r" % step) min, max, value = _get_min_max_value(o[0], o[1], step=step) if all(isinstance(_, int) for _ in o): cls = IntSliderWidget else: cls = FloatSliderWidget return cls(value=value, min=min, max=max, step=step) 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) or isinstance(abbrev, fixed): 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, kwargs): """Get an abbreviation for a function parameter.""" name = param.name kind = param.kind ann = param.annotation default = param.default empty = Parameter.empty not_found = (None, None) if kind == Parameter.POSITIONAL_OR_KEYWORD: if name in kwargs: yield name, kwargs.pop(name) elif ann is not empty: if default is empty: yield name, ann else: yield name, ann elif default is not empty: yield name, default else: yield not_found elif kind == Parameter.KEYWORD_ONLY: if name in kwargs: yield name, kwargs.pop(name) elif ann is not empty: yield name, ann elif default is not empty: yield name, default else: yield not_found 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 def _find_abbreviations(f, kwargs): """Find the abbreviations for a function and kwargs passed to interact.""" new_kwargs = [] for param in signature(f).parameters.values(): for name, value in _yield_abbreviations_for_parameter(param, kwargs): if value is None: raise ValueError('cannot find widget or abbreviation for argument: {!r}'.format(name)) new_kwargs.append((name, value)) return 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(__interact_f, **kwargs): """Build a group of widgets to interact with a function.""" f = __interact_f co = kwargs.pop('clear_output', True) kwargs_widgets = [] container = ContainerWidget() container.result = None container.args = [] container.kwargs = dict() kwargs = kwargs.copy() new_kwargs = _find_abbreviations(f, 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, **{n:v for n,v in new_kwargs}) # Now build the widgets from the abbreviations. 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. We skip any objects (such as fixed) that # are not DOMWidgets. c = [w for w in kwargs_widgets if isinstance(w, DOMWidget)] container.children = c # Build the callback def call_f(name, old, new): container.kwargs = {} for widget in kwargs_widgets: value = widget.value container.kwargs[widget.description] = value if co: clear_output(wait=True) try: container.result = f(**container.kwargs) except Exception as e: ip = get_ipython() if ip is None: container.log.warn("Exception in interact callback: %s", e, exc_info=True) else: ip.showtraceback() # Wire up the widgets 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(__interact_f=None, **kwargs): """interact(f, **kwargs) Interact with a function using widgets.""" # positional arg support in: https://gist.github.com/8851331 if __interact_f is not None: # This branch handles the cases: # 1. interact(f, **kwargs) # 2. @interact # def f(*args, **kwargs): # ... f = __interact_f w = interactive(f, **kwargs) f.widget = w display(w) return f else: # This branch handles the case: # @interact(a=30, b=40) # def f(*args, **kwargs): # ... def dec(f): w = interactive(f, **kwargs) f.widget = w display(w) return f return dec class fixed(HasTraits): """A pseudo-widget whose value is fixed and never synced to the client.""" value = Any(help="Any Python object") description = Unicode('', help="Any Python object") def __init__(self, value, **kwargs): super(fixed, self).__init__(value=value, **kwargs)