From: Vivien Maisonneuve Date: Wed, 2 Jul 2014 04:53:14 +0000 (+0200) Subject: Better implementation of symbols and constants X-Git-Tag: 1.0~173 X-Git-Url: https://scm.cri.ensmp.fr/git/linpy.git/commitdiff_plain/c3d305942999eeb429c6941184b47e7f1b55c499 Better implementation of symbols and constants --- diff --git a/pypol/linexprs.py b/pypol/linexprs.py index 3aef337..9449219 100644 --- a/pypol/linexprs.py +++ b/pypol/linexprs.py @@ -83,7 +83,7 @@ class Expression: def coefficient(self, symbol): if isinstance(symbol, Symbol): - symbol = str(symbol) + symbol = symbol.name elif not isinstance(symbol, str): raise TypeError('symbol must be a string or a Symbol instance') try: @@ -339,8 +339,9 @@ class Expression: class Symbol(Expression): - __slots__ = Expression.__slots__ + ( + __slots__ = ( '_name', + '_hash', ) def __new__(cls, name): @@ -350,11 +351,7 @@ class Symbol(Expression): raise TypeError('name must be a string or a Symbol instance') name = name.strip() self = object().__new__(cls) - self._coefficients = OrderedDict([(name, 1)]) - self._constant = 0 - self._symbols = tuple(name) self._name = name - self._dimension = 1 self._hash = hash(self._name) return self @@ -362,9 +359,40 @@ class Symbol(Expression): def name(self): return self._name + def __hash__(self): + return self._hash + + def coefficient(self, symbol): + if isinstance(symbol, Symbol): + symbol = symbol.name + elif not isinstance(symbol, str): + raise TypeError('symbol must be a string or a Symbol instance') + if symbol == self.name: + return 1 + else: + return 0 + + def coefficients(self): + yield self.name, 1 + + @property + def constant(self): + return 0 + + @property + def symbols(self): + return self.name, + + @property + def dimension(self): + return 1 + def issymbol(self): return True + def __eq__(self, other): + return isinstance(other, Symbol) and self.name == other.name + @classmethod def _fromast(cls, node): if isinstance(node, ast.Module) and len(node.body) == 1: @@ -395,21 +423,48 @@ def symbols(names): class Constant(Expression): + __slots__ = ( + '_constant', + '_hash', + ) + def __new__(cls, numerator=0, denominator=None): self = object().__new__(cls) if denominator is None and isinstance(numerator, Constant): self._constant = numerator.constant else: self._constant = Fraction(numerator, denominator) - self._coefficients = OrderedDict() - self._symbols = () - self._dimension = 0 self._hash = hash(self._constant) return self + def __hash__(self): + return self._hash + + def coefficient(self, symbol): + if isinstance(symbol, Symbol): + symbol = symbol.name + elif not isinstance(symbol, str): + raise TypeError('symbol must be a string or a Symbol instance') + return 0 + + def coefficients(self): + yield from [] + + @property + def symbols(self): + return () + + @property + def dimension(self): + return 0 + def isconstant(self): return True + @_polymorphic + def __eq__(self, other): + return isinstance(other, Constant) and self.constant == other.constant + def __bool__(self): return self.constant != 0