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#------------------------------------------------------------------------------
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# Copyright (c) 2005, Enthought, Inc.
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# This software is provided without warranty under the terms of the BSD
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# license included in enthought/LICENSE.txt and may be redistributed only
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# under the conditions described in the aforementioned license. The license
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# is also available online at http://www.enthought.com/licenses/BSD.txt
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# Thanks for using Enthought open source!
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# Author: David C. Morrill
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#------------------------------------------------------------------------------
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""" Define the ViewElements class, which is used to define a (typically
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class-based) hierarchical name space of related ViewElement objects.
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Normally there is a ViewElements object associated with each Traits-based
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class, which contains all of the ViewElement objects associated with the
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class. The ViewElements object is also linked to the ViewElements objects
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of its associated class's parent classes.
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#-------------------------------------------------------------------------------
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#-------------------------------------------------------------------------------
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from __future__ import absolute_import
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from traits.api import HasStrictTraits, List, Dict, Str, Int, Any, TraitError
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from traits.trait_base import enumerate
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from .view_element import ViewElement
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#-------------------------------------------------------------------------------
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#-------------------------------------------------------------------------------
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# Trait for contents of a ViewElements object
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content_trait = Dict( str, ViewElement )
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#-------------------------------------------------------------------------------
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# 'ViewElements' class:
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#-------------------------------------------------------------------------------
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class ViewElements ( HasStrictTraits ):
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""" Defines a hierarchical name space of related ViewElement objects.
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#---------------------------------------------------------------------------
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#---------------------------------------------------------------------------
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# Dictionary containing the named ViewElement items
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content = content_trait
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#---------------------------------------------------------------------------
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# Finds a specified ViewElement within the specified (optional) search
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#---------------------------------------------------------------------------
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def find ( self, name, stack = None ):
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""" Finds a specified ViewElement within the specified (optional) search
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# Assume search starts from the beginning the of the search order:
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# If a stack was specified, see if there is a matching entry in the
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# Match found, resume search at next ViewElements object
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# in the search order:
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# Search for a matching name starting at the specified ViewElements
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# object in the search order:
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for j, ves in enumerate( self._get_search_order()[i:] ):
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result = ves.content.get( name )
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if result is not None:
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# Match found. If there is a stack, push matching name and
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# ViewElements context onto it:
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stack[0:0] = [ SearchStackItem( id = name,
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# Return the ViewElement object that matched the name:
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# Indicate no match was found:
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#---------------------------------------------------------------------------
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# Returns a sorted list of all names accessible from the ViewElements
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# object that are of a specified (ViewElement) type:
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#---------------------------------------------------------------------------
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def filter_by ( self, klass = None ):
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""" Returns a sorted list of all names accessible from the ViewElements
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object that are of a specified (ViewElement) type.
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# Add each item in the search order which is of the right class and
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# which is not already in the result list:
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for ves in self._get_search_order():
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for name, ve in ves.content.items():
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if isinstance( ve, klass ) and (name not in result):
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result.append( name )
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# Sort the resulting list of names:
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#---------------------------------------------------------------------------
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# Handles the 'parents' list being updated:
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#---------------------------------------------------------------------------
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def _parents__changed ( self ):
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self._search_order = None
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def _parents_items_changed ( self ):
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self._search_order = None
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#---------------------------------------------------------------------------
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# Returns the current search order (computing it if necessary):
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#---------------------------------------------------------------------------
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def _get_search_order ( self ):
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if self._search_order is None:
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self._search_order = self._mro()
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return self._search_order
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#---------------------------------------------------------------------------
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# Compute the Python 'C3' algorithm used to determine a class's 'mro'
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# and apply it to the 'parents' of the ViewElements to determine the
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# correct search order:
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#---------------------------------------------------------------------------
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[ parent._get_search_order()[:] for parent in self.parents ] +
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[ self.parents[:] ] )
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def _merge ( self, seqs ):
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# Remove any empty sequences from the list:
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seqs = [ seq for seq in seqs if len( seq ) > 0 ]
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# Find merge candidates among the sequence heads:
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if len( [ s for s in seqs if candidate in s[1:] ] ) == 0:
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raise TraitError, "Inconsistent ViewElements hierarchy"
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# Add the candidate to the result:
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result.append( candidate )
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# Then remove the candidate:
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if seq[0] == candidate:
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#---------------------------------------------------------------------------
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# Returns a 'pretty print' version of the ViewElements object:
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#---------------------------------------------------------------------------
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def __repr__ ( self ):
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""" Returns a "pretty print" version of the ViewElements object.
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return self.content.__repr__()
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#-------------------------------------------------------------------------------
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# Define forward reference traits:
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#-------------------------------------------------------------------------------
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ViewElements.add_class_trait( 'parents', List( ViewElements ) )
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ViewElements.add_class_trait( '_search_order', Any )
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#-------------------------------------------------------------------------------
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# 'SearchStackItem' class:
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#-------------------------------------------------------------------------------
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class SearchStackItem ( HasStrictTraits ):
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#---------------------------------------------------------------------------
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#---------------------------------------------------------------------------
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# Name that was looked up
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# Index into the 'mro' list of ViewElements that the ID was found in
added
removed
traitsui/view_elements.py
