de.uka.ilkd.key.rule.join

Class CloseAfterJoin

java.lang.Object

de.uka.ilkd.key.rule.join.CloseAfterJoin

All Implemented Interfaces:

BuiltInRule, Rule

public class CloseAfterJoin
extends Object
implements BuiltInRule

Rule for closing a partner goal after a join operation. It does so by adding a formula corresponding to the new join node as an implicative premise to the goal to close; if the join rule is sound, the such manipulated goal should be closable by KeY. This particular way for closing partner goals should ensure that proofs can only be closed for sound join rules, i.e. rules producing join states that are weakenings of the parent states.

TODO: If a user attempts to prune away a "closed" partner node, he/she should also be asked whether the corresponding join node should also be pruned. Otherwise, the user might accidentally make it harder to close the whole proof (Add this to the bug tracker after merging the join branch into master).

Author:

Dominic Scheurer

Field Summary

Fields

Modifier and Type	Field and Description
private static String	DISPLAY_NAME
static CloseAfterJoin	INSTANCE
private static String	JOIN_GENERATE_IS_WEAKENING_GOAL_CFG
private static String	JOIN_GENERATE_IS_WEAKENING_GOAL_CFG_ON
private static String	JOINED_NODE_IS_WEAKENING_TITLE
private static Name	RULE_NAME

Constructor Summary

Constructors

Modifier	Constructor and Description
private	CloseAfterJoin()

Method Summary

Modifier and Type	Method and Description
private Term	allClosure(Term term, HashSet<Function> constsToReplace, Services services) Universally closes all logical variables in the given term.
ImmutableList<Goal>	apply(Goal goal, Services services, RuleApp ruleApp) the rule is applied on the given goal using the information of rule application.
CloseAfterJoinRuleBuiltInRuleApp	createApp(PosInOccurrence pio, Node thePartnerNode, Node correspondingJoinNode, SymbolicExecutionState joinNodeState, SymbolicExecutionState partnerState, Term pc) Creates a complete CloseAfterJoinBuiltInRuleApp.
IBuiltInRuleApp	createApp(PosInOccurrence pos, TermServices services)
String	displayName() returns the display name of the rule
private Term	getSyntacticWeakeningFormula(Services services, CloseAfterJoinRuleBuiltInRuleApp closeApp) Constructs the actual syntactic weakening formula \phi(s1, s2) expressing that s2 is a weakening of s1.
boolean	isApplicable(Goal goal, PosInOccurrence pio) returns true iff a rule is applicable at the given position.
boolean	isApplicableOnSubTerms()
Name	name() the name of the rule

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

JOIN_GENERATE_IS_WEAKENING_GOAL_CFG

private static final String JOIN_GENERATE_IS_WEAKENING_GOAL_CFG

See Also:

Constant Field Values

JOIN_GENERATE_IS_WEAKENING_GOAL_CFG_ON

private static final String JOIN_GENERATE_IS_WEAKENING_GOAL_CFG_ON

See Also:

Constant Field Values

JOINED_NODE_IS_WEAKENING_TITLE

private static final String JOINED_NODE_IS_WEAKENING_TITLE

See Also:

Constant Field Values

DISPLAY_NAME

private static final String DISPLAY_NAME

See Also:

Constant Field Values

RULE_NAME

private static final Name RULE_NAME

INSTANCE

public static final CloseAfterJoin INSTANCE

Constructor Detail

CloseAfterJoin

private CloseAfterJoin()

Method Detail

name

public Name name()

Description copied from interface: Rule

the name of the rule

Specified by:

name in interface Rule

displayName

public String displayName()

Description copied from interface: Rule

returns the display name of the rule

Specified by:

displayName in interface Rule

apply

public ImmutableList<Goal> apply(Goal goal,
                                 Services services,
                                 RuleApp ruleApp)
                          throws RuleAbortException

Description copied from interface: Rule

the rule is applied on the given goal using the information of rule application.

Specified by:

apply in interface Rule

Parameters:

goal - the Goal on which to apply ruleApp

services - the Services with the necessary information about the java programs

ruleApp - the rule application to be executed

Returns:

all open goals below \old(goal.node()), i.e. the goals resulting from the rule application

Throws:

RuleAbortException

getSyntacticWeakeningFormula

private Term getSyntacticWeakeningFormula(Services services,
                                          CloseAfterJoinRuleBuiltInRuleApp closeApp)

Constructs the actual syntactic weakening formula \phi(s1, s2) expressing that s2 is a weakening of s1.

Parameters:

services - The services object.

closeApp - The rule application containing the required data.

Returns:

The syntactic weakening formula for this.joinState and this.thisSEState.

allClosure

private Term allClosure(Term term,
                        HashSet<Function> constsToReplace,
                        Services services)

Universally closes all logical variables in the given term. Before, all Skolem constants in the term are replaced by fresh logical variables, where multiple occurrences of the same constant are replaced by the same variable.

Parameters:

term - Term to universally close.

constsToReplace - Skolem constants to replace before the universal closure.

services - The services object.

Returns:

A new term which is equivalent to the universal closure of the argument term, with Skolem constants in constsToReplace having been replaced by fresh variables before.

isApplicable

public boolean isApplicable(Goal goal,
                            PosInOccurrence pio)

Description copied from interface: BuiltInRule

returns true iff a rule is applicable at the given position. This does not necessarily mean that a rule application will change the goal (this decision is made due to performance reasons)

Specified by:

isApplicable in interface BuiltInRule

isApplicableOnSubTerms

public boolean isApplicableOnSubTerms()

Specified by:

isApplicableOnSubTerms in interface BuiltInRule

createApp

public IBuiltInRuleApp createApp(PosInOccurrence pos,
                                 TermServices services)

Specified by:

createApp in interface BuiltInRule

createApp

public CloseAfterJoinRuleBuiltInRuleApp createApp(PosInOccurrence pio,
                                                  Node thePartnerNode,
                                                  Node correspondingJoinNode,
                                                  SymbolicExecutionState joinNodeState,
                                                  SymbolicExecutionState partnerState,
                                                  Term pc)

Creates a complete CloseAfterJoinBuiltInRuleApp.

Parameters:

pio - Position of the Update-ProgramCounter formula.

thePartnerNode - The partner node to close.

correspondingJoinNode - The corresponding join node that is not closed. This is needed to add a reference to its parent in the partner goal at the place of this rule application.

joinNodeState - The SE state for the join node; needed for adding an implicative premise ensuring the soundness of join rules.

partnerState - The SE state for the partner node.

pc - The program counter common to the two states -- a formula of the form U\<{...}\> PHI, where U is an update in normal form and PHI is a DL formula).

Returns:

A complete CloseAfterJoinRuleBuiltInRuleApp.