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Commit b36a3c1f authored by LULUDBR\Lulu's avatar LULUDBR\Lulu
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Merge remote-tracking branch 'origin/master'

parents f323aa01 9f657295
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matcher/src/main/java/edu/kit/iti/formal/psdbg/termmatcher/MatcherFacade.java
View file @ b36a3c1f
package edu.kit.iti.formal.psdbg.termmatcher;
import de.uka.ilkd.key.java.Services;
import de.uka.ilkd.key.logic.Semisequent;
import de.uka.ilkd.key.logic.Sequent;
import de.uka.ilkd.key.logic.Term;
......@@ -21,8 +22,8 @@ import org.apache.logging.log4j.Logger;
public class MatcherFacade {
private static Logger logger = LogManager.getLogger(MatcherFacade.class);
public static Matchings matches(String pattern, Term keyTerm) {
MatcherImpl matcher = new MatcherImpl();
public static Matchings matches(String pattern, Term keyTerm, Services services) {
MatcherImpl matcher = new MatcherImpl(services);
matcher.setCatchAll(false);
MatchPatternParser mpp = getParser(pattern);
MatchPatternParser.TermPatternContext ctx = mpp.termPattern();
......@@ -50,12 +51,13 @@ public class MatcherFacade {
* @param pattern Semisequent pattern e.g. f(x), f(x)
* @param semiSeq Concrete KeY Semisequent
* @param catchAll
* @param services
* @return Matchings
*/
public static Matchings matches(String pattern, Semisequent semiSeq, boolean catchAll) {
public static Matchings matches(String pattern, Semisequent semiSeq, boolean catchAll, Services services) {
MatchPatternParser mpp = getParser(pattern);
MatchPatternParser.SemiSeqPatternContext ctx = mpp.semiSeqPattern();
MatcherImpl matcher = new MatcherImpl();
MatcherImpl matcher = new MatcherImpl(services);
matcher.setCatchAll(catchAll);
Matchings m = matcher.accept(ctx, MatchPathFacade.createRoot(semiSeq));
return m;
......@@ -67,9 +69,10 @@ public class MatcherFacade {
*
* @param pattern e.g., f(x) ==> f(y)
* @param sequent
* @param services
* @return
*/
public static Matchings matches(String pattern, Sequent sequent, boolean catchAll) {
public static Matchings matches(String pattern, Sequent sequent, boolean catchAll, Services services) {
MatchPatternParser mpp = getParser(pattern);
MatchPatternParser.SequentPatternContext ctx = mpp.sequentPattern();
logger.info("Matching \n" + pattern + "\n" + sequent.toString());
......@@ -78,21 +81,22 @@ public class MatcherFacade {
return new Matchings();
}
MatcherImpl matcher = new MatcherImpl();
MatcherImpl matcher = new MatcherImpl(services);
matcher.setCatchAll(catchAll);
Matchings m = matcher.accept(ctx, MatchPathFacade.create(sequent));
return m;
}
/**
* Like {@link #matches(String, Sequent)} but allows to use
* Like {@link #matches(String, Sequent, Services)} but allows to use
* MatcherImpl#isCatchAll.
*
* @param pattern
* @param sequent
* @param services
* @return
*/
public static Matchings matches(String pattern, Sequent sequent) {
return matches(pattern, sequent, true);
public static Matchings matches(String pattern, Sequent sequent, Services services) {
return matches(pattern, sequent, true, services);
}
}
matcher/src/main/java/edu/kit/iti/formal/psdbg/termmatcher/MatcherImpl.java
View file @ b36a3c1f
package edu.kit.iti.formal.psdbg.termmatcher;
import com.google.common.collect.Sets;
import de.uka.ilkd.key.logic.Semisequent;
import de.uka.ilkd.key.logic.SequentFormula;
import de.uka.ilkd.key.logic.Term;
import de.uka.ilkd.key.java.Services;
import de.uka.ilkd.key.logic.*;
import de.uka.ilkd.key.logic.op.QuantifiableVariable;
import edu.kit.formal.psdb.termmatcher.MatchPatternLexer;
import edu.kit.formal.psdb.termmatcher.MatchPatternParser;
import edu.kit.iti.formal.psdbg.termmatcher.mp.MatchPath;
import static edu.kit.iti.formal.psdbg.termmatcher.mp.MatchPathFacade.*;
import lombok.Getter;
import lombok.RequiredArgsConstructor;
import lombok.Setter;
import org.antlr.v4.runtime.CommonToken;
import org.antlr.v4.runtime.Token;
......@@ -20,21 +19,24 @@ import java.util.stream.Collectors;
import java.util.stream.IntStream;
import java.util.stream.Stream;
import static edu.kit.iti.formal.psdbg.termmatcher.mp.MatchPathFacade.*;
/**
* Matchpattern visitor visits the matchpatterns of case-statements
*
* @author Alexander Weigl
* @author S. Grebing
*/
@RequiredArgsConstructor
class MatcherImpl extends MatchPatternDualVisitor<Matchings, MatchPath> {
static final Matchings NO_MATCH = new Matchings();
static final Matchings EMPTY_MATCH = Matchings.singleton("EMPTY_MATCH", null);
static final Map<String, MatchPath> EMPTY_VARIABLE_ASSIGNMENT = EMPTY_MATCH.first();
@Getter
private final Services services;
Random random = new Random(42L);
/*
* Reduce two matchinfos
*
......@@ -67,7 +69,6 @@ class MatcherImpl extends MatchPatternDualVisitor<Matchings, MatchPath> {
}
*/
private List<Integer> currentPosition = new ArrayList<>();
/**
* If true, we assume every term in the pattern has a binder.
* The binding names are generated.
......@@ -79,17 +80,28 @@ class MatcherImpl extends MatchPatternDualVisitor<Matchings, MatchPath> {
private boolean catchAll = false;
private static HashMap<String, MatchPath> reduceConform(Map<String, MatchPath> h1, Map<String, MatchPath> h2) {
HashMap<String, MatchPath> listOfElementsofH1 = new HashMap<>(h1);
HashMap<String, MatchPath> h3 = new HashMap<>(h1);
for (String s1 : listOfElementsofH1.keySet()) {
for (String s1 : h3.keySet()) {
if (!s1.equals("EMPTY_MATCH") && (h2.containsKey(s1) && !h2.get(s1).equals(h1.get(s1)))) {
return null;
}
if (!s1.equals("EMPTY_MATCH") && h2.containsKey(s1)) {
if (h2.get(s1) instanceof MatchPath.MPQuantifiableVariable &&
!((QuantifiableVariable) h2.get(s1).getUnit()).name().toString().equals(h1.get(s1).toString())) {
return null;
}
if (h1.get(s1) instanceof MatchPath.MPQuantifiableVariable &&
!((QuantifiableVariable) h1.get(s1).getUnit()).name().toString().equals(h2.get(s1).toString())) {
return null;
}
if (!h2.get(s1).equals(h1.get(s1))) {
return null;
}
}
}
h3.putAll(h2);
return h3;
listOfElementsofH1.putAll(h2);
return listOfElementsofH1;
}
/**
......@@ -122,6 +134,7 @@ class MatcherImpl extends MatchPatternDualVisitor<Matchings, MatchPath> {
return oneMatch ? m3 : NO_MATCH;
}
/**
* Transform a number term into an int value.
* <p>
......@@ -449,11 +462,17 @@ class MatcherImpl extends MatchPatternDualVisitor<Matchings, MatchPath> {
QuantifiableVariable qv = toMatch.boundVars().get(i);
if (qfPattern.getType() == MatchPatternLexer.DONTCARE) {
match = reduceConform(match, Matchings.singleton(qfPattern.getText(), new MatchPath.MPQuantifiableVarible(peek, qv, i)));
//match = reduceConform(match, Matchings.singleton(qfPattern.getText(), new MatchPath.MPQuantifiableVarible(peek, qv, i)));
match = reduceConform(match, EMPTY_MATCH);
continue;
}
if (qfPattern.getType() == MatchPatternLexer.SID) {
match = reduceConform(match, Matchings.singleton(qfPattern.getText(), new MatchPath.MPQuantifiableVarible(peek, qv, i)));
TermFactory tf = new TermFactory(new HashMap<>());
TermBuilder tb = new TermBuilder(tf, services);
Term termQVariable = tb.var(qv);
match = reduceConform(match, Matchings.singleton(qfPattern.getText(),
new MatchPath.MPTerm(peek, termQVariable, -i)));
} else {
if (!qv.name().toString().equals(qfPattern.getText())) {
return NO_MATCH;
......@@ -464,8 +483,17 @@ class MatcherImpl extends MatchPatternDualVisitor<Matchings, MatchPath> {
Matchings fromTerm = accept(ctx.skope, create(peek, 0));
//return handleBindClause(ctx.bindClause(), path, m);
Matchings retM = reduceConformQuant(fromTerm, match);
Matchings retM = reduceConform(fromTerm, match);
retM.forEach(stringMatchPathMap -> {
stringMatchPathMap.forEach((s, matchPath) -> {
if (matchPath instanceof MatchPath.MPQuantifiableVariable) {
//create term from variablename and put instead into map
}
}
);
});
return handleBindClause(ctx.bindClause(), peek, retM);
}
......@@ -532,33 +560,6 @@ class MatcherImpl extends MatchPatternDualVisitor<Matchings, MatchPath> {
}
private Matchings reduceConformQuant(Matchings fromTerm, Matchings match) {
Matchings ret = new Matchings();
Map<String, MatchPath> quantifiedVarMap = match.first();
List<Map<String, MatchPath>> list = fromTerm.stream().filter(
map -> map.entrySet().stream().allMatch(
entry -> {
if (entry.getValue() != null) {
MatchPath mp = (MatchPath) entry.getValue();
Term mterm = (Term) mp.getUnit();
if (quantifiedVarMap.containsKey(entry.getKey())) {
return ((QuantifiableVariable) quantifiedVarMap.get(entry.getKey()).getUnit()).name().toString().
equals(mterm.op().name().toString());
} else {
return true;
}
} else {
return true;
}
}
)
).collect(Collectors.toList());
ret.addAll(list);
return ret;
}
@Override
public Matchings visitExprParen(MatchPatternParser.ExprParenContext ctx, MatchPath peek) {
......@@ -618,6 +619,39 @@ class MatcherImpl extends MatchPatternDualVisitor<Matchings, MatchPath> {
}
public int getRandomNumber() {
return random.nextInt();
return Math.abs(random.nextInt());
}
}
/* private Matchings reduceConformQuant(Matchings fromTerm, Matchings match) {
Matchings ret = new Matchings();
Map<String, MatchPath> quantifiedVarMap = match.first();
System.out.println("quantifiedVarMap = " + quantifiedVarMap);
List<Map<String, MatchPath>> list = fromTerm.stream().filter(
map -> map.entrySet().stream().allMatch(
entry -> {
System.out.println("entry = " + entry);
if (entry.getValue() != null) {
MatchPath mp = (MatchPath) entry.getValue();
Term mterm = (Term) mp.getUnit();
if (quantifiedVarMap.containsKey(entry.getKey())) {
QuantifiableVariable unit = (QuantifiableVariable) quantifiedVarMap.get(entry.getKey()).getUnit();
return unit.name().toString().
equals(mterm.op().name().toString());
} else {
return true;
}
} else {
//in this case we have an empty match, however, we may have bound quantVars, we need to add them
System.out.println("entry.getKey() = " + entry.getKey());
return true;
}
}
)
).collect(Collectors.toList());
ret.addAll(list);
return ret;
}*/
\ No newline at end of file
matcher/src/main/java/edu/kit/iti/formal/psdbg/termmatcher/mp/MatchPath.java
View file @ b36a3c1f
......@@ -47,9 +47,9 @@ public abstract class MatchPath<T, P> {
return unit.toString();
}
public static final class MPQuantifiableVarible extends MatchPath<QuantifiableVariable, Object> {
public static final class MPQuantifiableVariable extends MatchPath<QuantifiableVariable, Object> {
public MPQuantifiableVarible(MatchPath<? extends Object, ?> parent, QuantifiableVariable unit, int pos) {
public MPQuantifiableVariable(MatchPath<? extends Object, ?> parent, QuantifiableVariable unit, int pos) {
super(parent, unit, pos);
}
......@@ -75,7 +75,7 @@ public abstract class MatchPath<T, P> {
}
public static class MPTerm extends MatchPath<Term, Object> {
MPTerm(MatchPath<? extends Object, ?> parent, Term unit, int pos) {
public MPTerm(MatchPath<? extends Object, ?> parent, Term unit, int pos) {
super(parent, unit, pos);
}
......
matcher/src/test/java/edu/kit/iti/formal/psdbg/termmatcher/MatcherFacadeTest.java
View file @ b36a3c1f
......@@ -59,7 +59,11 @@ public class MatcherFacadeTest {
shouldMatchForm("fint2(1,i)", "fint2(1,i)");
shouldMatchForm("\\exists int i; fint2(1,i)", "(\\exists _ _)");
shouldMatchForm("\\exists int i; fint2(1,i)", "(\\exists _ ?Term)");
shouldMatchForm("\\exists int i; fint2(1,i)", "(\\exists ?X _)");
shouldMatchForm("\\exists int i; fint2(1,i)", "(\\exists ?X (fint2(1,?X)))");
shouldMatchForm("\\exists int i; \\exists int j; fint2(j,i)", "(\\exists i (\\exists j _))");
......@@ -119,26 +123,26 @@ public class MatcherFacadeTest {
private void shouldMatch(String key, String pattern) throws ParserException {
Term term = parseKeyTerm(key);
Matchings m = MatcherFacade.matches(pattern, term);
Matchings m = MatcherFacade.matches(pattern, term, services);
System.out.println(m);
}
private void shouldMatch(String key, String pattern, String exp) throws ParserException {
Term term = parseKeyTerm(key);
Matchings m = MatcherFacade.matches(pattern, term);
Matchings m = MatcherFacade.matches(pattern, term, services);
System.out.println(m);
Assert.assertEquals(exp, m.toString());
}
private void shouldMatchForm(String form, String pattern) throws ParserException {
Term formula = parserFormula(form);
Matchings m = MatcherFacade.matches(pattern, formula);
Matchings m = MatcherFacade.matches(pattern, formula, services);
System.out.println(m);
}
private void shouldMatchForm(String form, String pattern, String exp) throws ParserException {
Term formula = parserFormula(form);
Matchings m = MatcherFacade.matches(pattern, formula);
Matchings m = MatcherFacade.matches(pattern, formula, services);
System.out.println(m);
Assert.assertEquals(exp, m.toString());
}
......@@ -193,14 +197,14 @@ public class MatcherFacadeTest {
private void shouldMatchSemiSeq(String s, String s1, String exp) throws ParserException {
Sequent term = parseSeq(s);
Matchings m = MatcherFacade.matches(s1, term);
Matchings m = MatcherFacade.matches(s1, term, services);
System.out.println(m);
Assert.assertEquals(exp, m.toString());
}
private void shouldMatchSemiSeq(String s, String s1) throws ParserException {
Sequent term = parseSeq(s);
Matchings m = MatcherFacade.matches(s1, term);
Matchings m = MatcherFacade.matches(s1, term, services);
System.out.println(m);
}
......@@ -290,7 +294,7 @@ public class MatcherFacadeTest {
private void shouldMatchSeq(String seq, String seqPattern, String exp) throws ParserException {
Sequent sequent = parseSeq(seq);
Matchings m = MatcherFacade.matches(seqPattern, sequent);
Matchings m = MatcherFacade.matches(seqPattern, sequent, services);
System.out.println(m);
Assert.assertEquals(removeNumbersInBinders(m), exp);
}
......@@ -304,7 +308,7 @@ public class MatcherFacadeTest {
private void shouldMatchSeq(String seq, String seqPattern) throws ParserException {
Sequent sequent = parseSeq(seq);
Matchings m = MatcherFacade.matches(seqPattern, sequent);
Matchings m = MatcherFacade.matches(seqPattern, sequent, services);
System.out.println(m);
}
}
\ No newline at end of file
matcher/src/test/java/edu/kit/iti/formal/psdbg/termmatcher/TestUpdateMatch.java
View file @ b36a3c1f
......@@ -3,6 +3,7 @@ package edu.kit.iti.formal.psdbg.termmatcher;
import de.uka.ilkd.key.api.KeYApi;
import de.uka.ilkd.key.api.ProofApi;
import de.uka.ilkd.key.api.ProofManagementApi;
import de.uka.ilkd.key.java.Services;
import de.uka.ilkd.key.logic.Sequent;
import de.uka.ilkd.key.proof.init.ProofInputException;
import de.uka.ilkd.key.proof.io.ProblemLoaderException;
......@@ -19,7 +20,8 @@ public class TestUpdateMatch {
ProofApi pa = a.startProof(a.getProofContracts().get(0));
Sequent sequent = pa.getProof().root().sequent();
System.out.println(sequent);
Matchings result = MatcherFacade.matches("... update-application(_, ?X) ...", sequent, false);
Matchings result = MatcherFacade.matches("... update-application(_, ?X) ...",
sequent, false, null);
System.out.println(result);
String exp = normalize("\\<{exc=null;try { result=self.foo(_x)@Test;} catch (java.lang.Throwable e) { exc=e; } }\\> (and(and(and(gt(result,Z(0(#))),java.lang.Object::<inv>(heap,self)),equals(exc,null)),all{f:Field}(all{o:java.lang.Object}(or(or(elementOf(o,f,allLocs),and(not(equals(o,null)),not(equals(boolean::select(heapAtPre,o,java.lang.Object::<created>),TRUE)))),equals(any::select(heap,o,f),any::select(heapAtPre,o,f)))))))");
String x = normalize(result.iterator().next().get("?X").getUnit().toString().replace("\n", " "));
......
rt-key/src/main/java/edu/kit/iti/formal/psdbg/interpreter/InterpreterBuilder.java
View file @ b36a3c1f
......@@ -114,8 +114,7 @@ public class InterpreterBuilder {
}
public InterpreterBuilder addKeyMatcher(ProofApi api) {
ScriptApi scriptApi = api.getScriptApi();
interpreter.setMatcherApi(new KeYMatcher(scriptApi, interpreter));
interpreter.setMatcherApi(new KeYMatcher(api.getEnv().getServices()));
return this;
}
......
rt-key/src/main/java/edu/kit/iti/formal/psdbg/interpreter/KeYMatcher.java
View file @ b36a3c1f
package edu.kit.iti.formal.psdbg.interpreter;
import de.uka.ilkd.key.api.ScriptApi;
import de.uka.ilkd.key.api.VariableAssignments;
import de.uka.ilkd.key.api.ProofApi;
import de.uka.ilkd.key.java.Services;
import de.uka.ilkd.key.logic.Name;
import de.uka.ilkd.key.logic.Term;
import de.uka.ilkd.key.logic.op.SchemaVariable;
......@@ -18,14 +18,13 @@ import edu.kit.iti.formal.psdbg.interpreter.data.KeyData;
import edu.kit.iti.formal.psdbg.interpreter.data.SortType;
import edu.kit.iti.formal.psdbg.interpreter.data.VariableAssignment;
import edu.kit.iti.formal.psdbg.parser.ast.Signature;
import edu.kit.iti.formal.psdbg.parser.ast.Variable;
import edu.kit.iti.formal.psdbg.parser.data.Value;
import edu.kit.iti.formal.psdbg.parser.types.SimpleType;
import edu.kit.iti.formal.psdbg.parser.types.TermType;
import edu.kit.iti.formal.psdbg.parser.types.Type;
import edu.kit.iti.formal.psdbg.termmatcher.MatcherFacade;
import edu.kit.iti.formal.psdbg.termmatcher.Matchings;
import edu.kit.iti.formal.psdbg.termmatcher.mp.MatchPath;
import lombok.Getter;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.key_project.util.collection.ImmutableList;
......@@ -44,13 +43,13 @@ public class KeYMatcher implements MatcherApi<KeyData> {
private static final Logger LOGGER = LogManager.getLogger(KeYMatcher.class);
private static final Name CUT_TACLET_NAME = new Name("cut");
private ScriptApi scrapi;
private KeyInterpreter interpreter;
private List<MatchResult> resultsFromLabelMatch;
public KeYMatcher(ScriptApi scrapi, KeyInterpreter interpreter) {
this.scrapi = scrapi;
this.interpreter = interpreter;
@Getter
private Services services;
public KeYMatcher(Services services) {
this.services = services;
}
/**
......@@ -162,75 +161,6 @@ public class KeYMatcher implements MatcherApi<KeyData> {
return assignments.isEmpty()? null: assignments;
}
/**
* Match against a sequent of a goal node
* @param currentState
* @param term
* @param signature
* @return
*/
//@Override
public List<VariableAssignment> matchSeqKeY(GoalNode<KeyData> currentState,
String term,
Signature signature) {
VariableAssignment interpreterAssignments = currentState.getAssignments();
VariableAssignments keyAssignments = new VariableAssignments(null);
interpreterAssignments.getTypes().forEach((k, v) -> keyAssignments.getTypeMap().put(k.getIdentifier(), interpreter.getTypeConversionBiMap().get(v)));
interpreterAssignments.getValues().forEach((k, v) -> {
try {
keyAssignments.addAssignment(k.getIdentifier(), v);
} catch (Exception e) {
e.printStackTrace();
}
});
Set<Map.Entry<Variable, Type>> sigEntrySet = signature.entrySet();
sigEntrySet.forEach(e -> {
try {
keyAssignments.addType(e.getKey().getIdentifier(), interpreter.getTypeConversionBiMap().get(e.getValue()));
} catch (Exception e1) {
e1.printStackTrace();
}
});
// System.out.println("Matching: "+term.toString()+"\n================\n"+currentState.getData().getNode().sequent()+"\n================\n");
List<VariableAssignments> keyMatchResult = scrapi.matchPattern(term, currentState.getData().getNode().sequent(), keyAssignments);
//empty keyassignments
// System.out.println("Matched " + keyMatchResult.size() + " goals from " + currentState.toString() + " with pattern " + term);
List<VariableAssignment> transformedMatchResults = new ArrayList<>();
for (VariableAssignments mResult : keyMatchResult) {
transformedMatchResults.add(from(mResult, currentState.getData()));
}
//keyMatchResult.forEach(r -> transformedMatchResults.add(from(r)));
return transformedMatchResults;
}
/**
* Transforms a KeY Variable Assignment into an assignment for the interpreter
*
* @param keyAssignments
* @param currentState
* @return
*/
public VariableAssignment from(VariableAssignments keyAssignments, KeyData currentState) {
VariableAssignment interpreterAssignments = new VariableAssignment(null);
Map<String, VariableAssignments.VarType> keyTypeMap = keyAssignments.getTypeMap();
keyTypeMap.entrySet().forEach(e -> interpreterAssignments.declare(e.getKey(), interpreter.getTypeConversionBiMap().inverse().get(e.getValue())));
keyTypeMap.keySet().forEach(k -> {
try {
interpreterAssignments.assign(k, toValueTerm(currentState, (Term) keyAssignments.getVarValue(k)));
//System.out.println(keyAssignments.getVarValue(k));
} catch (Exception e) {
e.printStackTrace();
}
});
return interpreterAssignments;
}
private Value<String> toValueTerm(KeyData currentState, Term matched) {
String reprTerm = LogicPrinter.quickPrintTerm(matched, currentState.getEnv().getServices());
......@@ -241,11 +171,14 @@ public class KeYMatcher implements MatcherApi<KeyData> {
}
@Override
public List<VariableAssignment> matchSeq(GoalNode<KeyData> currentState, String data, Signature sig) {
public List<VariableAssignment> matchSeq(GoalNode<KeyData> currentState,
String data,
Signature sig) {
//System.out.println("State that will be matched " + currentState.getData().getNode().sequent() + " with pattern " + data);
//System.out.println("Signature " + sig.toString());
Matchings m = MatcherFacade.matches(data, currentState.getData().getNode().sequent(), false);
Matchings m = MatcherFacade.matches(data,
currentState.getData().getNode().sequent(), false, services);
if (m.isEmpty()) {
LOGGER.debug("currentState has no match= " + currentState.getData().getNode().sequent());
......
rt/src/main/java/edu/kit/iti/formal/psdbg/interpreter/dbg/StepIntoReverseCommand.java
View file @ b36a3c1f
......@@ -15,5 +15,6 @@ public class StepIntoReverseCommand<T> extends DebuggerCommand<T> {
info("There is no previous state to the current one.");
}
dbg.setStatePointer(stepBack);
}
}
rt/src/main/java/edu/kit/iti/formal/psdbg/interpreter/dbg/StepOverReverseCommand.java
View file @ b36a3c1f
package edu.kit.iti.formal.psdbg.interpreter.dbg;
import lombok.val;
public class StepOverReverseCommand<T> extends DebuggerCommand<T> {
@Override
public void execute(DebuggerFramework<T> dbg) throws DebuggerException {
val statePointer = dbg.getCurrentStatePointer();
PTreeNode<T> stepOverReverse = statePointer.getStepInvInto() != null ?
statePointer.getStepInvInto() :
statePointer.getStepInvOver();
if (stepOverReverse == null) {
info("There is no previous state to the current one.");