idp_solver.Expression¶
(They are monkeypatched by other modules)

class
idp_solver.Expression.
Expression
[source]¶ Bases:
idp_solver.Expression.ASTNode
The abstract class of AST nodes representing (sub)expressions.

code
¶ Textual representation of the expression. Often used as a key.
It is generated from the subtree. Some tree transformations change it (e.g., instantiate), others don’t.
 Type
string

sub_exprs
¶ The children of the AST node.
The list may be reduced by simplification.
 Type
List[Expression]

type
¶ The name of the type of the expression, e.g.,
bool
. Type
string

co_constraint
¶ A constraint attached to the node.
For example, the co_constraint of
square(length(top()))
issquare(length(top())) = length(top())*length(top()).
, assumingsquare
is appropriately defined.The co_constraint of a defined symbol applied to arguments is the instantiation of the definition for those arguments. This is useful for definitions over infinite domains, as well as to compute relevant questions.
 Type
Expression, optional

simpler
¶ A simpler, equivalent expression.
Equivalence is computed in the context of the theory and structure. Simplifying an expression is useful for efficiency and to compute relevant questions.
 Type
Expression, optional

value
¶ A rigid term equivalent to the expression, obtained by transformation.
Equivalence is computed in the context of the theory and structure.
 Type
Optional[Expression]

annotations
¶ The set of annotations given by the expert in the IDP source code.
annotations['reading']
is the annotation giving the intended meaning of the expression (in English). Type
Dict

original
¶ The original expression, before transformation.
 Type

fresh_vars
¶ The set of names of the variables in the expression.
 Type
Set(string)

collect
(questions, all_=True, co_constraints=True)[source]¶ collects the questions in self.
questions is an OrderedSet of Expression Questions are the terms and the simplest subformula that can be evaluated. collect uses the simplified version of the expression.
all_=False : ignore expanded formulas and AppliedSymbol interpreted in a structure co_constraints=False : ignore co_constraints
default implementation for Constructor, IfExpr, AUnary, Variable, Number_constant, Brackets

generate_constructors
(constructors: dict)[source]¶ fills the list constructors with all constructors belonging to open types.

unknown_symbols
(co_constraints=True)[source]¶ returns the list of symbol declarations in self, ignoring type constraints
returns Dict[name, Declaration]

co_constraints
(co_constraints)[source]¶ collects the constraints attached to AST nodes, e.g. instantiated definitions
`co_constraints is an OrderedSet of Expression

is_assignment
() → bool[source]¶  Returns
True if self assigns a rigid term to a rigid function application
 Return type
bool

substitute
(e0, e1, assignments, todo=None)¶ recursively substitute e0 by e1 in self (e0 is not a Variable)
implementation for everything but AppliedSymbol, UnappliedSymbol and Fresh_variable

instantiate
(e0, e1)¶ recursively substitute Variable e0 by e1 in self
instantiating e0=`x by e1=`f in self=`x(y) returns f(y) (or any instance of f if arities don’t match)

interpret
(problem) → idp_solver.Expression.Expression¶ uses information in the problem and its vocabulary to:  expand quantifiers in the expression  simplify the expression using known assignments  instantiate definitions
 Parameters
problem (Problem) – the Problem to apply
 Returns
the resulting expression
 Return type

symbolic_propagate
(assignments: idp_solver.Assignments.Assignments, truth: Optional[idp_solver.Expression.Constructor] = true) → List[Tuple[idp_solver.Expression.Expression, idp_solver.Expression.Constructor]]¶ returns the consequences of self=truth that are in assignments.
The consequences are obtained by symbolic processing (no calls to Z3).
 Parameters
assignments (Assignments) – The set of questions to chose from. Their value is ignored.
truth (Constructor, optional) – The truth value of the expression self. Defaults to TRUE.
 Returns
A list of pairs (Expression, bool), descring the literals that are implicant

propagate1
(assignments, truth)¶ returns the list of symbolic_propagate of self (default implementation)

as_set_condition
() → Tuple[Optional[AppliedSymbol], Optional[bool], Optional[Enumeration]][source]¶ Returns an equivalent expression of the type “x in y”, or None
 Returns
meaning “expr is (not) in enumeration”
 Return type
Tuple[Optional[AppliedSymbol], Optional[bool], Optional[Enumeration]]


class
idp_solver.Expression.
Constructor
(**kwargs)[source]¶ Bases:
idp_solver.Expression.Expression

update_exprs
(new_exprs)¶ change sub_exprs and simplify, while keeping relevant info.


class
idp_solver.Expression.
AQuantification
(**kwargs)[source]¶ Bases:
idp_solver.Expression.Expression

collect
(questions, all_=True, co_constraints=True)[source]¶ collects the questions in self.
questions is an OrderedSet of Expression Questions are the terms and the simplest subformula that can be evaluated. collect uses the simplified version of the expression.
all_=False : ignore expanded formulas and AppliedSymbol interpreted in a structure co_constraints=False : ignore co_constraints
default implementation for Constructor, IfExpr, AUnary, Variable, Number_constant, Brackets


class
idp_solver.Expression.
BinaryOperator
(**kwargs)[source]¶ Bases:
idp_solver.Expression.Expression

collect
(questions, all_=True, co_constraints=True)[source]¶ collects the questions in self.
questions is an OrderedSet of Expression Questions are the terms and the simplest subformula that can be evaluated. collect uses the simplified version of the expression.
all_=False : ignore expanded formulas and AppliedSymbol interpreted in a structure co_constraints=False : ignore co_constraints
default implementation for Constructor, IfExpr, AUnary, Variable, Number_constant, Brackets


class
idp_solver.Expression.
AAggregate
(**kwargs)[source]¶ Bases:
idp_solver.Expression.Expression

collect
(questions, all_=True, co_constraints=True)[source]¶ collects the questions in self.
questions is an OrderedSet of Expression Questions are the terms and the simplest subformula that can be evaluated. collect uses the simplified version of the expression.
all_=False : ignore expanded formulas and AppliedSymbol interpreted in a structure co_constraints=False : ignore co_constraints
default implementation for Constructor, IfExpr, AUnary, Variable, Number_constant, Brackets


class
idp_solver.Expression.
AppliedSymbol
(**kwargs)[source]¶ Bases:
idp_solver.Expression.Expression

collect
(questions, all_=True, co_constraints=True)[source]¶ collects the questions in self.
questions is an OrderedSet of Expression Questions are the terms and the simplest subformula that can be evaluated. collect uses the simplified version of the expression.
all_=False : ignore expanded formulas and AppliedSymbol interpreted in a structure co_constraints=False : ignore co_constraints
default implementation for Constructor, IfExpr, AUnary, Variable, Number_constant, Brackets

generate_constructors
(constructors: dict)[source]¶ fills the list constructors with all constructors belonging to open types.

substitute
(e0, e1, assignments, todo=None)¶ recursively substitute e0 by e1 in self

update_exprs
(new_exprs)¶ change sub_exprs and simplify, while keeping relevant info.


class
idp_solver.Expression.
UnappliedSymbol
(**kwargs)[source]¶ Bases:
idp_solver.Expression.Expression
The result of parsing a symbol not applied to arguments. Can be a constructor, a quantified variable, or a symbol application without arguments (by abuse of notation, e.g. ‘p’). (The parsing of numbers result directly in Number nodes)
Converted to the proper AST class by annotate().

collect
(questions, all_=True, co_constraints=True)[source]¶ collects the questions in self.
questions is an OrderedSet of Expression Questions are the terms and the simplest subformula that can be evaluated. collect uses the simplified version of the expression.
all_=False : ignore expanded formulas and AppliedSymbol interpreted in a structure co_constraints=False : ignore co_constraints
default implementation for Constructor, IfExpr, AUnary, Variable, Number_constant, Brackets

update_exprs
(new_exprs)¶ change sub_exprs and simplify, while keeping relevant info.


class
idp_solver.Expression.
Variable
(name, sort)[source]¶ Bases:
idp_solver.Expression.Expression
AST node for a variable in a quantification or aggregate

update_exprs
(new_exprs)¶ change sub_exprs and simplify, while keeping relevant info.


class
idp_solver.Expression.
Number
(**kwargs)[source]¶ Bases:
idp_solver.Expression.Expression

update_exprs
(new_exprs)¶ change sub_exprs and simplify, while keeping relevant info.
