2022-05-23 00:16:32 +04:00

198 lines
5.2 KiB
Python

from ..utils import SchemaBase
class DatumType(object):
"""An object to assist in building Vega-Lite Expressions"""
def __repr__(self):
return "datum"
def __getattr__(self, attr):
if attr.startswith("__") and attr.endswith("__"):
raise AttributeError(attr)
return GetAttrExpression("datum", attr)
def __getitem__(self, attr):
return GetItemExpression("datum", attr)
def __call__(self, datum, **kwargs):
"""Specify a datum for use in an encoding"""
return dict(datum=datum, **kwargs)
datum = DatumType()
def _js_repr(val):
"""Return a javascript-safe string representation of val"""
if val is True:
return "true"
elif val is False:
return "false"
elif val is None:
return "null"
else:
return repr(val)
class Expression(SchemaBase):
"""Expression
Base object for enabling build-up of Javascript expressions using
a Python syntax. Calling ``repr(obj)`` will return a Javascript
representation of the object and the operations it encodes.
"""
_schema = {"type": "string"}
def to_dict(self, *args, **kwargs):
return repr(self)
def __setattr__(self, attr, val):
# We don't need the setattr magic defined in SchemaBase
return object.__setattr__(self, attr, val)
def __add__(self, other):
return BinaryExpression("+", self, other)
def __radd__(self, other):
return BinaryExpression("+", other, self)
def __sub__(self, other):
return BinaryExpression("-", self, other)
def __rsub__(self, other):
return BinaryExpression("-", other, self)
def __mul__(self, other):
return BinaryExpression("*", self, other)
def __rmul__(self, other):
return BinaryExpression("*", other, self)
def __truediv__(self, other):
return BinaryExpression("/", self, other)
def __rtruediv__(self, other):
return BinaryExpression("/", other, self)
__div__ = __truediv__
__rdiv__ = __rtruediv__
def __mod__(self, other):
return BinaryExpression("%", self, other)
def __rmod__(self, other):
return BinaryExpression("%", other, self)
def __pow__(self, other):
# "**" Javascript operator is not supported in all browsers
return FunctionExpression("pow", (self, other))
def __rpow__(self, other):
# "**" Javascript operator is not supported in all browsers
return FunctionExpression("pow", (other, self))
def __neg__(self):
return UnaryExpression("-", self)
def __pos__(self):
return UnaryExpression("+", self)
# comparison operators
def __eq__(self, other):
return BinaryExpression("===", self, other)
def __ne__(self, other):
return BinaryExpression("!==", self, other)
def __gt__(self, other):
return BinaryExpression(">", self, other)
def __lt__(self, other):
return BinaryExpression("<", self, other)
def __ge__(self, other):
return BinaryExpression(">=", self, other)
def __le__(self, other):
return BinaryExpression("<=", self, other)
def __abs__(self):
return FunctionExpression("abs", (self,))
# logical operators
def __and__(self, other):
return BinaryExpression("&&", self, other)
def __rand__(self, other):
return BinaryExpression("&&", other, self)
def __or__(self, other):
return BinaryExpression("||", self, other)
def __ror__(self, other):
return BinaryExpression("||", other, self)
def __invert__(self):
return UnaryExpression("!", self)
# item access
def __getitem__(self, val):
return GetItemExpression(self, val)
class UnaryExpression(Expression):
def __init__(self, op, val):
super(UnaryExpression, self).__init__(op=op, val=val)
def __repr__(self):
return "({op}{val})".format(op=self.op, val=_js_repr(self.val))
class BinaryExpression(Expression):
def __init__(self, op, lhs, rhs):
super(BinaryExpression, self).__init__(op=op, lhs=lhs, rhs=rhs)
def __repr__(self):
return "({lhs} {op} {rhs})".format(
op=self.op, lhs=_js_repr(self.lhs), rhs=_js_repr(self.rhs)
)
class FunctionExpression(Expression):
def __init__(self, name, args):
super(FunctionExpression, self).__init__(name=name, args=args)
def __repr__(self):
args = ",".join(_js_repr(arg) for arg in self.args)
return "{name}({args})".format(name=self.name, args=args)
class ConstExpression(Expression):
def __init__(self, name, doc):
self.__doc__ = """{}: {}""".format(name, doc)
super(ConstExpression, self).__init__(name=name, doc=doc)
def __repr__(self):
return str(self.name)
class GetAttrExpression(Expression):
def __init__(self, group, name):
super(GetAttrExpression, self).__init__(group=group, name=name)
def __repr__(self):
return "{}.{}".format(self.group, self.name)
class GetItemExpression(Expression):
def __init__(self, group, name):
super(GetItemExpression, self).__init__(group=group, name=name)
def __repr__(self):
return "{}[{!r}]".format(self.group, self.name)