psamm.expression.boolean – Boolean expressions

Representations of boolean expressions and variables.

These classes can be used to represent simple boolean expressions and do evaluation with substitutions of particular variables.

class psamm.expression.boolean.Variable(symbol)

Represents a variable in a boolean expression

class psamm.expression.boolean.And(*args)

Represents an AND term in an expression.

class psamm.expression.boolean.Or(*args)

Represents an OR term in an expression.

exception psamm.expression.boolean.SubstitutionError

Error substituting into expression.

class psamm.expression.boolean.Expression(arg, _vars=None)

Boolean expression representation.

The expression can be constructed from an expression string of variables, operators (“and”, “or”) and parenthesis groups. For example,

>>> e = Expression('a and (b or c)')

root

Return root term, variable or boolean of the expression.

variables

Immutable set of variables in the expression.

has_value()

Return True if the expression has no variables.

value

The value of the expression if fully evaluated.

substitute(mapping)

Substitute variables using mapping function.

exception psamm.expression.boolean.ParseError(*args, **kwargs)

Signals error parsing boolean expression.