3 d @s\dZddlmZddlmZddZddZd d ZeZd d Z d dZ ddZ ddZ dS)a Utility routines that convert objects to CTrait instances Most of these functions depend on objects having an informal ``as_ctrait`` interface if they know how to turn themselves into a CTrait instance. We need to special-case ``TraitType`` subclasses so that we can use them in trait definitions without needing to call them, eg.:: x = Float rather than:: x = Float() To handle this, there is another informal interface with the deliberately unwieldy classmethod name ``instantiate_and_get_ctrait``. )partial) DefaultValuec Cs"yt|Stk rdSXdS)zD Convert to a CTrait if the object knows how, else return None. N) as_ctrait TypeError)objr9/tmp/pip-build-7vycvbft/traits/traits/trait_converters.py trait_cast"sr cCsLt|trt|dr|jSt|t r:t|dr:|jStdj|dS)a Convert to CTrait if the object knows how, else raise TraitError. Parameters ---------- obj An object that supports conversion to `CTrait`. Refer documentation for when the object supports this conversion. Returns ------- ctrait.CTrait A CTrait object. Raises ------ TypeError If the object does not support conversion to CTrait. instantiate_and_get_ctraitrz1Object {!r} does not support conversion to CTraitN) isinstancetypehasattrr rrformat)rrrr r+s rc Cs"yt|Stk r|SXdS)zl Returns either the original value or a valid CTrait if the value can be converted to a CTrait. N)rr)traitrrr check_traitGsrc CsPddlm}ddlm}|dkr*|jSyt|Stk rJ||SXdS)z- Returns a trait derived from its input. r)Any)TraitN) trait_typesrtraitsrrr)rrrrrr trait_fromUs   rc Cs2ddlm}yt|Stk r,||SXdS)z; Returns the trait corresponding to a specified value. r)rN)rrrr)rrrrr trait_fores  rcCst||}|jj|S)a Callable providing default for a shadow trait of a mapped trait pair. Parameters ---------- trait : CTrait The principal trait of the mapped trait pair. name : str The name of the trait on the relevant HasTraits object. instance : HasTraits The HasTraits object on which the mapped trait lives. Returns ------- default : object The default value for the shadow trait. )getattrhandlerZ mapped_value)rnameinstancevaluerrr _mapped_trait_defaultts rcCs8ddlm}|ddddj}|jtjtt|||S)a Returns the 'mapped trait' definition for a mapped trait, the default value of which is a callable that maps the value of the original trait. Parameters ---------- trait : ctrait.CTrait A trait for which the 'mapped trait' definition is being created. name : str The name of the trait for which the 'mapped trait' definition is being created. Returns ------- trait_types.Any A definition of the 'mapped trait' r)rFT)is_baseZ transienteditable)rrrZset_default_valuercallablerr)rrrZ mapped_traitrrr mapped_trait_fors r!N) __doc__ functoolsr constantsrr rrZtry_trait_castrrrr!rrrr s