/lib/galaxy/util/expressions.py
Python | 37 lines | 4 code | 0 blank | 33 comment | 3 complexity | 84fd38adcb6563a6467538ee780eba94 MD5 | raw file
- """
- Expression evaluation support.
- For the moment this depends on python's eval. In the future it should be
- replaced with a "safe" parser.
- """
- from UserDict import DictMixin
- class ExpressionContext( object, DictMixin ):
- def __init__( self, dict, parent=None ):
- """
- Create a new expression context that looks for values in the
- container object 'dict', and falls back to 'parent'
- """
- self.dict = dict
- self.parent = parent
- def __getitem__( self, key ):
- if key in self.dict:
- return self.dict[key]
- if self.parent is not None and key in self.parent:
- return self.parent[key]
- raise KeyError( key )
- def __setitem__( self, key, value ):
- self.dict[key] = value
- def __contains__( self, key ):
- if key in self.dict:
- return True
- if self.parent is not None and key in self.parent:
- return True
- return False
- def __str__( self ):
- return str( self.dict )
- def __nonzero__( self ):
- if not self.dict and not self.parent:
- return False
- return True