Fixed #17754 -- Refactored gis.measure
This refactoring does allow much easier MeasureBase subclassing. Many thanks to Ricardo di Virgilio for the initial patch.
This commit is contained in:
Claude Paroz
parent
fe873e2765
commit
4d46106f8c
1
AUTHORS
1
AUTHORS
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@ -161,6 +161,7 @@ answer newbie questions, and generally made Django that much better:
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Rajesh Dhawan <rajesh.dhawan@gmail.com>
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Sander Dijkhuis <sander.dijkhuis@gmail.com>
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Jordan Dimov <s3x3y1@gmail.com>
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Riccardo Di Virgilio
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Nebojša Dorđević
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dne@mayonnaise.net
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dready <wil@mojipage.com>
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@ -30,7 +30,7 @@
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Distance and Area objects to allow for sensible and convienient calculation
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and conversions.
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Authors: Robert Coup, Justin Bronn
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Authors: Robert Coup, Justin Bronn, Riccardo Di Virgilio
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Inspired by GeoPy (http://exogen.case.edu/projects/geopy/)
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and Geoff Biggs' PhD work on dimensioned units for robotics.
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@ -40,13 +40,134 @@ from decimal import Decimal
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from django.utils.functional import total_ordering
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NUMERIC_TYPES = (int, float, long, Decimal)
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AREA_PREFIX = "sq_"
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def pretty_name(obj):
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return obj.__name__ if obj.__class__ == type else obj.__class__.__name__
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@total_ordering
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class MeasureBase(object):
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STANDARD_UNIT = None
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ALIAS = {}
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UNITS = {}
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LALIAS = {}
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def __init__(self, default_unit=None, **kwargs):
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value, self._default_unit = self.default_units(kwargs)
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setattr(self, self.STANDARD_UNIT, value)
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if default_unit and isinstance(default_unit, basestring):
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self._default_unit = default_unit
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def _get_standard(self):
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return getattr(self, self.STANDARD_UNIT)
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def _set_standard(self, value):
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setattr(self, self.STANDARD_UNIT, value)
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standard = property(_get_standard, _set_standard)
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def __getattr__(self, name):
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if name in self.UNITS:
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return self.standard / self.UNITS[name]
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else:
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raise AttributeError('Unknown unit type: %s' % name)
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def __repr__(self):
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return '%s(%s=%s)' % (pretty_name(self), self._default_unit,
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getattr(self, self._default_unit))
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def __str__(self):
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return '%s %s' % (getattr(self, self._default_unit), self._default_unit)
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# **** Comparison methods ****
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def __eq__(self, other):
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if isinstance(other, self.__class__):
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return self.standard == other.standard
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else:
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return NotImplemented
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def __lt__(self, other):
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if isinstance(other, self.__class__):
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return self.standard < other.standard
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else:
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return NotImplemented
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# **** Operators methods ****
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def __add__(self, other):
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if isinstance(other, self.__class__):
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return self.__class__(default_unit=self._default_unit,
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**{self.STANDARD_UNIT: (self.standard + other.standard)})
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else:
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raise TypeError('%(class)s must be added with %(class)s' % {"class":pretty_name(self)})
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def __iadd__(self, other):
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if isinstance(other, self.__class__):
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self.standard += other.standard
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return self
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else:
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raise TypeError('%(class)s must be added with %(class)s' % {"class":pretty_name(self)})
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def __sub__(self, other):
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if isinstance(other, self.__class__):
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return self.__class__(default_unit=self._default_unit,
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**{self.STANDARD_UNIT: (self.standard - other.standard)})
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else:
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raise TypeError('%(class)s must be subtracted from %(class)s' % {"class":pretty_name(self)})
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def __isub__(self, other):
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if isinstance(other, self.__class__):
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self.standard -= other.standard
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return self
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else:
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raise TypeError('%(class)s must be subtracted from %(class)s' % {"class":pretty_name(self)})
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def __mul__(self, other):
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if isinstance(other, NUMERIC_TYPES):
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return self.__class__(default_unit=self._default_unit,
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**{self.STANDARD_UNIT: (self.standard * other)})
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else:
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raise TypeError('%(class)s must be multiplied with number' % {"class":pretty_name(self)})
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def __imul__(self, other):
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if isinstance(other, NUMERIC_TYPES):
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self.standard *= float(other)
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return self
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else:
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raise TypeError('%(class)s must be multiplied with number' % {"class":pretty_name(self)})
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def __rmul__(self, other):
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return self * other
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def __div__(self, other):
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if isinstance(other, self.__class__):
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return self.standard / other.standard
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if isinstance(other, NUMERIC_TYPES):
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return self.__class__(default_unit=self._default_unit,
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**{self.STANDARD_UNIT: (self.standard / other)})
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else:
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raise TypeError('%(class)s must be divided with number or %(class)s' % {"class":pretty_name(self)})
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def __idiv__(self, other):
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if isinstance(other, NUMERIC_TYPES):
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self.standard /= float(other)
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return self
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else:
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raise TypeError('%(class)s must be divided with number' % {"class":pretty_name(self)})
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def __nonzero__(self):
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return bool(self.standard)
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def default_units(self, kwargs):
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"""
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Return the unit value and the default units specified
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from the given keyword arguments dictionary.
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"""
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val = 0.0
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default_unit = self.STANDARD_UNIT
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for unit, value in kwargs.iteritems():
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if not isinstance(value, float): value = float(value)
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if unit in self.UNITS:
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@ -86,8 +207,8 @@ class MeasureBase(object):
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else:
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raise Exception('Could not find a unit keyword associated with "%s"' % unit_str)
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@total_ordering
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class Distance(MeasureBase):
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STANDARD_UNIT = "m"
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UNITS = {
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'chain' : 20.1168,
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'chain_benoit' : 20.116782,
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@ -163,189 +284,33 @@ class Distance(MeasureBase):
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}
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LALIAS = dict([(k.lower(), v) for k, v in ALIAS.items()])
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def __init__(self, default_unit=None, **kwargs):
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# The base unit is in meters.
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self.m, self._default_unit = self.default_units(kwargs)
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if default_unit and isinstance(default_unit, str):
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self._default_unit = default_unit
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def __getattr__(self, name):
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if name in self.UNITS:
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return self.m / self.UNITS[name]
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else:
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raise AttributeError('Unknown unit type: %s' % name)
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def __repr__(self):
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return 'Distance(%s=%s)' % (self._default_unit, getattr(self, self._default_unit))
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def __str__(self):
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return '%s %s' % (getattr(self, self._default_unit), self._default_unit)
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def __eq__(self, other):
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if isinstance(other, Distance):
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return self.m == other.m
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else:
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return NotImplemented
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def __lt__(self, other):
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if isinstance(other, Distance):
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return self.m < other.m
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else:
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return NotImplemented
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def __add__(self, other):
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if isinstance(other, Distance):
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return Distance(default_unit=self._default_unit, m=(self.m + other.m))
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else:
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raise TypeError('Distance must be added with Distance')
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def __iadd__(self, other):
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if isinstance(other, Distance):
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self.m += other.m
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return self
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else:
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raise TypeError('Distance must be added with Distance')
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def __sub__(self, other):
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if isinstance(other, Distance):
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return Distance(default_unit=self._default_unit, m=(self.m - other.m))
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else:
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raise TypeError('Distance must be subtracted from Distance')
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def __isub__(self, other):
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if isinstance(other, Distance):
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self.m -= other.m
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return self
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else:
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raise TypeError('Distance must be subtracted from Distance')
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def __mul__(self, other):
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if isinstance(other, (int, float, long, Decimal)):
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return Distance(default_unit=self._default_unit, m=(self.m * float(other)))
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elif isinstance(other, Distance):
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return Area(default_unit='sq_' + self._default_unit, sq_m=(self.m * other.m))
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if isinstance(other, self.__class__):
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return Area(default_unit=AREA_PREFIX + self._default_unit,
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**{AREA_PREFIX + self.STANDARD_UNIT: (self.standard * other.standard)})
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elif isinstance(other, NUMERIC_TYPES):
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return self.__class__(default_unit=self._default_unit,
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**{self.STANDARD_UNIT: (self.standard * other)})
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else:
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raise TypeError('Distance must be multiplied with number or Distance')
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raise TypeError('%(distance)s must be multiplied with number or %(distance)s' % {
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"distance" : pretty_name(self.__class__),
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})
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def __imul__(self, other):
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if isinstance(other, (int, float, long, Decimal)):
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self.m *= float(other)
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return self
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else:
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raise TypeError('Distance must be multiplied with number')
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def __rmul__(self, other):
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return self * other
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def __div__(self, other):
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if isinstance(other, (int, float, long, Decimal)):
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return Distance(default_unit=self._default_unit, m=(self.m / float(other)))
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else:
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raise TypeError('Distance must be divided with number')
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def __idiv__(self, other):
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if isinstance(other, (int, float, long, Decimal)):
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self.m /= float(other)
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return self
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else:
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raise TypeError('Distance must be divided with number')
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def __nonzero__(self):
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return bool(self.m)
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@total_ordering
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class Area(MeasureBase):
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STANDARD_UNIT = AREA_PREFIX + Distance.STANDARD_UNIT
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# Getting the square units values and the alias dictionary.
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UNITS = dict([('sq_%s' % k, v ** 2) for k, v in Distance.UNITS.items()])
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ALIAS = dict([(k, 'sq_%s' % v) for k, v in Distance.ALIAS.items()])
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UNITS = dict([('%s%s' % (AREA_PREFIX, k), v ** 2) for k, v in Distance.UNITS.items()])
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ALIAS = dict([(k, '%s%s' % (AREA_PREFIX, v)) for k, v in Distance.ALIAS.items()])
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LALIAS = dict([(k.lower(), v) for k, v in ALIAS.items()])
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def __init__(self, default_unit=None, **kwargs):
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self.sq_m, self._default_unit = self.default_units(kwargs)
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if default_unit and isinstance(default_unit, str):
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self._default_unit = default_unit
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def __getattr__(self, name):
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if name in self.UNITS:
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return self.sq_m / self.UNITS[name]
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else:
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raise AttributeError('Unknown unit type: ' + name)
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def __repr__(self):
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return 'Area(%s=%s)' % (self._default_unit, getattr(self, self._default_unit))
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def __str__(self):
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return '%s %s' % (getattr(self, self._default_unit), self._default_unit)
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def __eq__(self, other):
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if isinstance(other, Area):
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return self.sq_m == other.sq_m
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else:
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return NotImplemented
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def __lt__(self, other):
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if isinstance(other, Area):
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return self.sq_m < other.sq_m
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else:
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return NotImplemented
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def __add__(self, other):
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if isinstance(other, Area):
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return Area(default_unit=self._default_unit, sq_m=(self.sq_m + other.sq_m))
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else:
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raise TypeError('Area must be added with Area')
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def __iadd__(self, other):
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if isinstance(other, Area):
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self.sq_m += other.sq_m
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return self
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else:
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raise TypeError('Area must be added with Area')
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def __sub__(self, other):
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if isinstance(other, Area):
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return Area(default_unit=self._default_unit, sq_m=(self.sq_m - other.sq_m))
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else:
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raise TypeError('Area must be subtracted from Area')
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def __isub__(self, other):
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if isinstance(other, Area):
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self.sq_m -= other.sq_m
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return self
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else:
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raise TypeError('Area must be subtracted from Area')
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def __mul__(self, other):
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if isinstance(other, (int, float, long, Decimal)):
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return Area(default_unit=self._default_unit, sq_m=(self.sq_m * float(other)))
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else:
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raise TypeError('Area must be multiplied with number')
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def __imul__(self, other):
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if isinstance(other, (int, float, long, Decimal)):
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self.sq_m *= float(other)
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return self
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else:
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raise TypeError('Area must be multiplied with number')
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def __rmul__(self, other):
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return self * other
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def __div__(self, other):
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if isinstance(other, (int, float, long, Decimal)):
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return Area(default_unit=self._default_unit, sq_m=(self.sq_m / float(other)))
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if isinstance(other, NUMERIC_TYPES):
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return self.__class__(default_unit=self._default_unit,
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**{self.STANDARD_UNIT: (self.standard / other)})
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else:
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raise TypeError('Area must be divided with number')
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raise TypeError('%(class)s must be divided by a number' % {"class":pretty_name(self)})
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def __idiv__(self, other):
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if isinstance(other, (int, float, long, Decimal)):
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self.sq_m /= float(other)
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return self
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else:
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raise TypeError('Area must be divided with number')
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def __nonzero__(self):
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return bool(self.sq_m)
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# Shortcuts
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D = Distance
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@ -93,6 +93,8 @@ class DistanceTest(unittest.TestCase):
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self.assertEqual(d4.m, 50)
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d4 /= 5
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self.assertEqual(d4.m, 10)
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d5 = d1 / D(m=2)
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self.assertEqual(d5, 50)
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a5 = d1 * D(m=10)
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self.assertTrue(isinstance(a5, Area))
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@ -102,10 +104,6 @@ class DistanceTest(unittest.TestCase):
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d1 *= D(m=1)
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self.fail('Distance *= Distance should raise TypeError')
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with self.assertRaises(TypeError):
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d5 = d1 / D(m=1)
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self.fail('Distance / Distance should raise TypeError')
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with self.assertRaises(TypeError):
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d1 /= D(m=1)
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self.fail('Distance /= Distance should raise TypeError')
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