From: Vivien Maisonneuve Date: Fri, 20 Jun 2014 07:46:01 +0000 (+0200) Subject: Improve Polyhedron.fromstring X-Git-Tag: 1.0~224 X-Git-Url: https://scm.cri.ensmp.fr/git/linpy.git/commitdiff_plain/156db05a9a4c4e6d71a431fcc6343b973ca1d5ab Improve Polyhedron.fromstring --- diff --git a/pypol/linear.py b/pypol/linear.py index 5b2dc80..8fdece9 100644 --- a/pypol/linear.py +++ b/pypol/linear.py @@ -97,8 +97,7 @@ class Expression: @classmethod def _fromast(cls, node): - if isinstance(node, ast.Module): - assert len(node.body) == 1 + if isinstance(node, ast.Module) and len(node.body) == 1: return cls._fromast(node.body[0]) elif isinstance(node, ast.Expr): return cls._fromast(node.value) @@ -106,9 +105,8 @@ class Expression: return Symbol(node.id) elif isinstance(node, ast.Num): return Constant(node.n) - elif isinstance(node, ast.UnaryOp): - if isinstance(node.op, ast.USub): - return -cls._fromast(node.operand) + elif isinstance(node, ast.UnaryOp) and isinstance(node.op, ast.USub): + return -cls._fromast(node.operand) elif isinstance(node, ast.BinOp): left = cls._fromast(node.left) right = cls._fromast(node.right) @@ -460,23 +458,20 @@ class Polyhedron: return self @classmethod - def fromstring(cls, string): - string = string.strip() - string = re.sub(r'^\{\s*|\s*\}$', '', string) - string = re.sub(r'([^<=>])=([^<=>])', r'\1==\2', string) - string = re.sub(r'(\d+|\))\s*([^\W\d_]\w*|\()', r'\1*\2', string) - equalities = [] - inequalities = [] - for cstr in re.split(r',|;|and|&&|/\\|∧', string, flags=re.I): - tree = ast.parse(cstr.strip(), 'eval') - if not isinstance(tree, ast.Module) or len(tree.body) != 1: - raise SyntaxError('invalid syntax') - node = tree.body[0] - if not isinstance(node, ast.Expr): - raise SyntaxError('invalid syntax') - node = node.value - if not isinstance(node, ast.Compare): - raise SyntaxError('invalid syntax') + def _fromast(cls, node): + if isinstance(node, ast.Module) and len(node.body) == 1: + return cls._fromast(node.body[0]) + elif isinstance(node, ast.Expr): + return cls._fromast(node.value) + elif isinstance(node, ast.BinOp) and isinstance(node.op, ast.BitAnd): + equalities1, inequalities1 = cls._fromast(node.left) + equalities2, inequalities2 = cls._fromast(node.right) + equalities = equalities1 + equalities2 + inequalities = inequalities1 + inequalities2 + return equalities, inequalities + elif isinstance(node, ast.Compare): + equalities = [] + inequalities = [] left = Expression._fromast(node.left) for i in range(len(node.ops)): op = node.ops[i] @@ -492,8 +487,23 @@ class Polyhedron: elif isinstance(op, ast.Gt): inequalities.append(left - right - 1) else: - raise SyntaxError('invalid syntax') + break left = right + else: + return equalities, inequalities + raise SyntaxError('invalid syntax') + + @classmethod + def fromstring(cls, string): + string = string.strip() + string = re.sub(r'^\{\s*|\s*\}$', '', string) + string = re.sub(r'([^<=>])=([^<=>])', r'\1==\2', string) + string = re.sub(r'(\d+|\))\s*([^\W\d_]\w*|\()', r'\1*\2', string) + tokens = re.split(r',|;|and|&&|/\\|∧', string, flags=re.I) + tokens = ['({})'.format(token) for token in tokens] + string = ' & '.join(tokens) + tree = ast.parse(string, 'eval') + equalities, inequalities = cls._fromast(tree) return cls(equalities, inequalities) @property @@ -681,8 +691,10 @@ class Polyhedron: { [i0, i1] : 2i1 >= -2 - i0 } ''' Empty = eq(0,1) + Universe = Polyhedron() + if __name__ == '__main__': p1 = Polyhedron('2a + 2b + 1 == 0') # empty print(p1._toisl())