X-Git-Url: https://scm.cri.ensmp.fr/git/linpy.git/blobdiff_plain/7fda4e3865bb7cc9b6ee15cfd3c62c207f585ec7..b4f536e238161d59db61f4bb5fc6e87d4b7baffe:/linpy/linexprs.py?ds=sidebyside diff --git a/linpy/linexprs.py b/linpy/linexprs.py index b5864e1..d2554a0 100644 --- a/linpy/linexprs.py +++ b/linpy/linexprs.py @@ -331,7 +331,7 @@ class LinExpr: return left / right raise SyntaxError('invalid syntax') - _RE_NUM_VAR = re.compile(r'(\d+|\))\s*([^\W\d_]\w*|\()') + _RE_NUM_VAR = re.compile(r'(\d+|\))\s*([^\W\d]\w*|\()') @classmethod def fromstring(cls, string): @@ -339,7 +339,7 @@ class LinExpr: Create an expression from a string. Raise SyntaxError if the string is not properly formatted. """ - # add implicit multiplication operators, e.g. '5x' -> '5*x' + # Add implicit multiplication operators, e.g. '5x' -> '5*x'. string = LinExpr._RE_NUM_VAR.sub(r'\1*\2', string) tree = ast.parse(string, 'eval') expr = cls._fromast(tree) @@ -416,7 +416,8 @@ class LinExpr: if symbol == sympy.S.One: constant = coefficient elif isinstance(symbol, sympy.Dummy): - # we cannot properly convert dummy symbols + # We cannot properly convert dummy symbols with respect to + # symbol equalities. raise TypeError('cannot convert dummy symbols') elif isinstance(symbol, sympy.Symbol): symbol = Symbol(symbol.name) @@ -450,6 +451,13 @@ class Symbol(LinExpr): Two instances of Symbol are equal if they have the same name. """ + __slots__ = ( + '_name', + '_constant', + '_symbols', + '_dimension', + ) + def __new__(cls, name): """ Return a symbol with the name string given in argument. @@ -463,12 +471,17 @@ class Symbol(LinExpr): raise SyntaxError('invalid syntax') self = object().__new__(cls) self._name = name - self._coefficients = {self: Fraction(1)} self._constant = Fraction(0) self._symbols = (self,) self._dimension = 1 return self + @property + def _coefficients(self): + # This is not implemented as an attribute, because __hash__ is not + # callable in __new__ in class Dummy. + return {self: Fraction(1)} + @property def name(self): """ @@ -553,15 +566,8 @@ class Dummy(Symbol): """ if name is None: name = 'Dummy_{}'.format(Dummy._count) - elif not isinstance(name, str): - raise TypeError('name must be a string') - self = object().__new__(cls) + self = super().__new__(cls, name) self._index = Dummy._count - self._name = name.strip() - self._coefficients = {self: Fraction(1)} - self._constant = Fraction(0) - self._symbols = (self,) - self._dimension = 1 Dummy._count += 1 return self @@ -586,6 +592,13 @@ class Rational(LinExpr, Fraction): fractions.Fraction classes. """ + __slots__ = ( + '_coefficients', + '_constant', + '_symbols', + '_dimension', + ) + Fraction.__slots__ + def __new__(cls, numerator=0, denominator=None): self = object().__new__(cls) self._coefficients = {}