2.2 KiB
Output Format
plasp
3 translates SAS and PDDL files into the same ASP fact format.
plasp
structures the translated ASP facts into the multiple sections, which are explained in the following.
Feature Requirements
Declares advanced features required by the input planning problem, such as conditional effects and axiom rules.
Feature requirements may be used in meta encodings to warn about unsupported features.
Syntax
syntax | description |
---|---|
requiresFeature(<feature name>). |
declares the feature <feature name> to be required by the input problem |
Currently, feature requirements are only recognized with SAS problems.
plasp
supports the following feature requirements:
SAS feature | description |
---|---|
actionCosts |
actions have associated costs |
axiomRules |
immediate actions are used, which are executed as soon as the preconditions are satisfied |
conditionalEffects |
some effects of an action may have additional conditions |
Example
The following specifies that the input problem has the two requirements actionCosts
and conditionalEffects
.
% requirements
requiresFeature(actionCosts).
requiresFeature(conditionalEffects).
Types (PDDL Only)
Specifies all object types used by the PDDL problem (only if typing is enabled).
Syntax
syntax | description |
---|---|
type(type(<type name>)). |
declares the type type(<type name>) |
has(<object>, type(<type name>)). |
declares <object> to be of type type(<type name>) |
Example
The following declares the type type(block)
for later usage by the problem:
% types
type(type(block)).
Constants may have associated types (here, constant(a)
):
constant(constant(a)).
has(constant(a), type(block)).
If there is typing information, variables are derived only for the allowed types (here, variable(clear(X))
with type(block)
):
variable(variable(clear(X))) :- has(X, type(block)).
Similarly, actions are derived in a type-safe way (here, action(stack(X, Y))
is only applicable to arguments of type(block)
):
action(action(stack(X, Y))) :- has(X, type(block)), has(Y, type(block)).