import abc
from types import SimpleNamespace
from rpy2.robjects.robject import RObjectMixin
import rpy2.rinterface as rinterface
from rpy2.rinterface import StrSexpVector
from rpy2.robjects import help as rhelp
from rpy2.robjects import conversion
_get_exported_value = rinterface.baseenv['::']
getmethod = _get_exported_value('methods', 'getMethod')
require = rinterface.baseenv.find('require')
require(StrSexpVector(('methods', )),
quietly=rinterface.BoolSexpVector((True, )))
[docs]class RS4(RObjectMixin, rinterface.SexpS4):
""" Python representation of an R instance of class 'S4'. """
[docs] def slotnames(self):
""" Return the 'slots' defined for this object """
return methods_env['slotNames'](self)
def do_slot(self, name):
return (conversion.get_conversion()
.rpy2py(super(RS4, self).do_slot(name)))
[docs] def extends(self):
"""Return the R classes this extends.
This calls the R function methods::extends()."""
return methods_env['extends'](self.rclass)
[docs] @staticmethod
def isclass(name):
""" Return whether the given name is a defined class. """
name = conversion.get_conversion().py2rpy(name)
return methods_env['isClass'](name)[0]
[docs] def validobject(self, test=False, complete=False):
""" Return whether the instance is 'valid' for its class. """
cv = conversion.get_conversion()
test = cv.py2rpy(test)
complete = cv.py2rpy(complete)
return methods_env['validObject'](self, test=test,
complete=complete)[0]
class ClassRepresentation(RS4):
""" Definition of an R S4 class """
slots = property(lambda x: [y[0] for y in x.do_slot('slots')],
None, None,
"Slots (attributes) for the class")
basenames = property(lambda x: [y[0] for y in x.do_slot('contains')],
None, None,
"Parent classes")
contains = basenames
isabstract = property(lambda x: x.do_slot('virtual')[0],
None, None,
"Is the class an abstract class ?")
virtual = isabstract
packagename = property(lambda x: x.do_slot('package')[0],
None, None,
"R package in which the class is defined")
package = packagename
classname = property(lambda x: x.do_slot('className')[0],
None, None,
"Name of the R class")
def getclassdef(cls_name: str, packagename=rinterface.MissingArg):
cls_def = methods_env['getClassDef'](
StrSexpVector((cls_name,)),
package=StrSexpVector((packagename, ))
)
cls_def = ClassRepresentation(cls_def)
cls_def.__rname__ = cls_name
return cls_def
class RS4_Type(abc.ABCMeta):
def __new__(mcs, name, bases, cls_dict):
try:
cls_rname = cls_dict['__rname__']
except KeyError:
cls_rname = name
try:
accessors = cls_dict['__accessors__']
except KeyError:
accessors = []
for rname, where, \
python_name, as_property, \
docstring in accessors:
if where is None:
where = rinterface.globalenv
else:
where = StrSexpVector(('package:%s' % where, ))
if python_name is None:
python_name = rname
signature = StrSexpVector((cls_rname, ))
r_meth = getmethod(StrSexpVector((rname, )),
signature=signature,
where=where)
r_meth = conversion.get_conversion().rpy2py(r_meth)
if as_property:
cls_dict[python_name] = property(r_meth, None, None,
doc=docstring)
else:
cls_dict[python_name] = lambda self: r_meth(self)
return type.__new__(mcs, name, bases, cls_dict)
# playground to experiment with more metaclass-level automation
[docs]class RS4Auto_Type(abc.ABCMeta):
""" This type (metaclass) takes an R S4 class
and create a Python class out of it,
copying the R documention page into the Python docstring.
A class with this metaclass has the following optional
attributes: __rname__, __rpackagename__, __attr__translation,
__meth_translation__.
"""
def __new__(mcs, name, bases, cls_dict):
try:
cls_rname = cls_dict['__rname__']
except KeyError:
cls_rname = name
try:
cls_rpackagename = cls_dict['__rpackagename__']
except KeyError:
cls_rpackagename = None
try:
cls_attr_translation = cls_dict['__attr_translation__']
except KeyError:
cls_attr_translation = {}
try:
cls_meth_translation = cls_dict['__meth_translation__']
except KeyError:
cls_meth_translation = {}
cls_def = getclassdef(cls_rname, cls_rpackagename)
# documentation / help
if cls_rpackagename is None:
cls_dict['__doc__'] = "Undocumented class from the R workspace."
else:
pack_help = rhelp.Package(cls_rpackagename)
page_help = None
try:
# R's classes are sometimes documented with a prefix 'class.'
page_help = pack_help.fetch('%s-class' % cls_def.__rname__)
except rhelp.HelpNotFoundError:
pass
if page_help is None:
try:
page_help = pack_help.fetch(cls_def.__rname__)
except rhelp.HelpNotFoundError:
pass
if page_help is None:
cls_dict['__doc__'] = ('Unable to fetch R documentation '
'for the class')
else:
cls_dict['__doc__'] = ''.join(page_help.to_docstring())
for slt_name in cls_def.slots:
# TODO: sanity check on the slot name
try:
slt_name = cls_attr_translation[slt_name]
except KeyError:
# no translation: abort
pass
# TODO: isolate the slot documentation and have it here
cls_dict[slt_name] = property(lambda self: self.do_slot(slt_name),
None, None,
None)
# Now tackle the methods
all_generics = methods_env['getGenerics']()
findmethods = methods_env['findMethods']
# does not seem elegant, but there is probably nothing else to do
# than loop across all generics
r_cls_rname = StrSexpVector((cls_rname, ))
for funcname in all_generics:
all_methods = findmethods(StrSexpVector((funcname, )),
classes=r_cls_rname)
# skip if no methods (issue #301). R's findMethods() result
# does not have an attribute "names" if of length zero.
if len(all_methods) == 0:
continue
# all_methods contains all method/signature pairs
# having the class we are considering somewhere in the signature
# (the R/S4 systems allows multiple dispatch)
for name, meth in zip(all_methods.do_slot("names"), all_methods):
# R/S4 is storing each method/signature as a string,
# with the argument type separated by the character '#'
# We will re-use that name for the Python name
# (no multiple dispatch in python, the method name
# will not be enough), replacing the '#'s with '__'s.
signature = name.split("#")
meth_name = '__'.join(signature)
# function names ending with '<-' indicate that the function
# is a setter of some sort. We reflect that by adding a 'set_'
# prefix to the Python name (and of course remove the
# suffix '<-').
if funcname.endswith('<-'):
meth_name = 'set_%s__%s' % (funcname[:-2], meth_name)
else:
meth_name = '%s__%s' % (funcname, meth_name)
# finally replace remaining '.'s in the Python name with '_'s
meth_name = meth_name.replace('.', '_')
# TODO: sanity check on the function name
try:
meth_name = cls_meth_translation[meth_name]
except KeyError:
# no translation: abort
pass
# TODO: isolate the slot documentation and have it here
if meth_name in cls_dict:
raise Exception("Duplicated attribute/method name.")
cls_dict[meth_name] = meth
return abc.ABCMeta.__new__(mcs, name, bases, cls_dict)
def set_accessors(cls, cls_name, where, acs):
# set accessors (to be abandonned for the metaclass above ?)
if where is None:
where = rinterface.globalenv
else:
where = "package:" + str(where)
where = StrSexpVector((where, ))
for r_name, python_name, as_property, docstring in acs:
if python_name is None:
python_name = r_name
r_meth = getmethod(StrSexpVector((r_name, )),
signature=StrSexpVector((cls_name, )),
where=where)
r_meth = conversion.get_conversion().rpy2py(r_meth)
if as_property:
setattr(cls, python_name, property(r_meth, None, None))
else:
setattr(cls, python_name, lambda self: r_meth(self))
def get_classnames(packname):
res = methods_env['getClasses'](
where=StrSexpVector(("package:%s" % packname, ))
)
return tuple(res)
# Namespace to store the definition of RS4 classes
rs4classes = SimpleNamespace()
def _getclass(rclsname):
if hasattr(rs4classes, rclsname):
rcls = getattr(rs4classes, rclsname)
else:
# dynamically create a class
rcls = type(rclsname,
(RS4, ),
dict())
setattr(rs4classes,
rclsname,
rcls)
return rcls
def rs4instance_factory(robj):
"""
Return an RS4 objects (R objects in the 'S4' class system)
as a Python object of type inheriting from `robjects.methods.RS4`.
The types are located in the namespace `robjects.methods.rs4classes`,
and a dummy type is dynamically created whenever necessary.
"""
clslist = None
if len(robj.rclass) > 1:
raise ValueError(
'Currently unable to handle more than one class per object'
)
for rclsname in robj.rclass:
rcls = _getclass(rclsname)
return rcls(robj)
if clslist is None:
return robj
methods_env = rinterface.baseenv.find('as.environment')(
StrSexpVector(('package:methods', ))
)