refactor: direct predicates

* Remove the direct keyword because it can be inferred
* Use may/must/current instead of value literals
* Transformation rule changes

4 files changed, 50 insertions, 56 deletions

diff --git a/subprojects/language/src/main/java/tools/refinery/language/Problem.xtext b/subprojects/language/src/main/java/tools/refinery/language/Problem.xtext
index c94d40ab..ba885e3c 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/Problem.xtext
+++ b/subprojects/language/src/main/java/tools/refinery/language/Problem.xtext
@@ -33,25 +33,19 @@ ReferenceDeclaration:
         name=Identifier
         ("opposite" opposite=[ReferenceDeclaration|QualifiedName])?;
 
-enum PredicateKind:
-        DIRECT="direct";
-
 PredicateDefinition:
-        (error?="error" "pred"? | kind=PredicateKind? "pred")
+        (error?="error" "pred"? | "pred")
         name=Identifier
         "(" (parameters+=Parameter ("," parameters+=Parameter)*)? ")"
         ("<->" bodies+=Conjunction (";" bodies+=Conjunction)*)?
         ".";
 
-enum RuleKind:
-        DIRECT="direct";
-
 RuleDefinition:
-        kind=RuleKind "rule"
+        "rule"
         name=Identifier
         "(" (parameters+=Parameter ("," parameters+=Parameter)*)? ")"
         (":" bodies+=Conjunction (";" bodies+=Conjunction)*
-        "~>" action=Action)?
+        "==>" consequents+=Consequent (";" consequents+=Consequent)*)?
         ".";
 
 Parameter:
@@ -60,45 +54,40 @@ Parameter:
 Conjunction:
         literals+=Literal ("," literals+=Literal)*;
 
-Action:
-        actionLiterals+=ActionLiteral ("," actionLiterals+=ActionLiteral)*;
+Consequent:
+        actions+=Action ("," actions+=Action)*;
 
 Literal:
-        Atom | ValueLiteral | NegativeLiteral;
-
-ValueLiteral:
-        atom=Atom
-        (refinement?=":" | "=")
-        values+=LogicConstant ("|" values+=LogicConstant)*;
+        Atom | NegativeLiteral;
 
 NegativeLiteral:
-        "!" atom=Atom;
+        modality=Modality? "!" atom=Atom;
 
-ActionLiteral:
-        ValueActionLiteral | DeleteActionLiteral | NewActionLiteral;
+Action:
+        AssertionAction | DeleteAction | NewAction;
 
-ValueActionLiteral:
-        atom=Atom
-        (refinement?=":" | "=")
-        value=LogicValue;
+AssertionAction:
+        value=ShortLogicValue? atom=Atom |
+        atom=Atom (overwrite?="=" | ":") value=LogicValue;
 
-DeleteActionLiteral:
+DeleteAction:
         "delete" variableOrNode=[VariableOrNode|QualifiedName];
 
-NewActionLiteral:
-        "new" variable=NewVariable;
+NewAction:
+        "new" variable=NewVariable (":" parent=[VariableOrNode|QualifiedName])?;
 
 NewVariable:
         name=Identifier;
 
+enum Modality:
+        MAY="may" | MUST="must" | CURRENT="current";
+
 Atom:
+        modality=Modality?
         relation=[Relation|QualifiedName]
         transitiveClosure?="+"?
         "(" (arguments+=Argument ("," arguments+=Argument)*)? ")";
 
-LogicConstant:
-        value=LogicValue;
-
 Argument:
         VariableOrNodeArgument | ConstantArgument;
 
@@ -185,7 +174,7 @@ QualifiedName hidden():
 
 Identifier:
         ID | "true" | "false" | "unknown" | "error" | "class" | "abstract" | "extends" | "enum" | "pred" |
-        "indiv" | "problem" | "new" | "delete" | "direct" | "rule";
+        "indiv" | "problem" | "new" | "delete" | "rule" | "may" | "must" | "current";
 
 Integer returns ecore::EInt hidden():
         "-"? INT;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/formatting2/ProblemFormatter.java b/subprojects/language/src/main/java/tools/refinery/language/formatting2/ProblemFormatter.java
index 903347f7..df5d2090 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/formatting2/ProblemFormatter.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/formatting2/ProblemFormatter.java
@@ -49,7 +49,7 @@ public class ProblemFormatter extends AbstractJavaFormatter {
                         doc.format(argument);
                 }
         }
-        
+
         protected void format(ClassDeclaration classDeclaration, IFormattableDocument doc) {
                 surroundNewLines(doc, classDeclaration, this::twoNewLines);
                 var region = regionFor(classDeclaration);
@@ -69,7 +69,6 @@ public class ProblemFormatter extends AbstractJavaFormatter {
         protected void format(PredicateDefinition predicateDefinition, IFormattableDocument doc) {
                 surroundNewLines(doc, predicateDefinition, this::twoNewLines);
                 var region = regionFor(predicateDefinition);
-                doc.append(region.feature(ProblemPackage.Literals.PREDICATE_DEFINITION__KIND), this::oneSpace);
                 doc.append(region.keyword("pred"), this::oneSpace);
                 doc.append(region.feature(ProblemPackage.Literals.NAMED_ELEMENT__NAME), this::noSpace);
                 formatParenthesizedList(region, doc);
@@ -98,12 +97,14 @@ public class ProblemFormatter extends AbstractJavaFormatter {
 
         protected void format(NegativeLiteral literal, IFormattableDocument doc) {
                 var region = regionFor(literal);
+                doc.append(region.feature(ProblemPackage.Literals.LITERAL__MODALITY), this::oneSpace);
                 doc.append(region.keyword("!"), this::noSpace);
                 doc.format(literal.getAtom());
         }
 
         protected void format(Atom atom, IFormattableDocument doc) {
                 var region = regionFor(atom);
+                doc.append(region.feature(ProblemPackage.Literals.LITERAL__MODALITY), this::oneSpace);
                 doc.append(region.feature(ProblemPackage.Literals.ATOM__RELATION), this::noSpace);
                 doc.append(region.feature(ProblemPackage.Literals.ATOM__TRANSITIVE_CLOSURE), this::noSpace);
                 formatParenthesizedList(region, doc);
diff --git a/subprojects/language/src/main/java/tools/refinery/language/resource/DerivedVariableComputer.java b/subprojects/language/src/main/java/tools/refinery/language/resource/DerivedVariableComputer.java
index bb1226c4..4d19006f 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/resource/DerivedVariableComputer.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/resource/DerivedVariableComputer.java
@@ -29,7 +29,6 @@ import tools.refinery.language.model.problem.Problem;
 import tools.refinery.language.model.problem.ProblemFactory;
 import tools.refinery.language.model.problem.ProblemPackage;
 import tools.refinery.language.model.problem.Statement;
-import tools.refinery.language.model.problem.ValueLiteral;
 import tools.refinery.language.model.problem.VariableOrNodeArgument;
 import tools.refinery.language.naming.NamingUtil;
 
@@ -72,9 +71,6 @@ public class DerivedVariableComputer {
                 for (Literal literal : conjunction.getLiterals()) {
                         if (literal instanceof Atom atom) {
                                 createSigletonVariablesAndCollectVariables(atom, knownVariables, newVariables);
-                        } else
-                        if (literal instanceof ValueLiteral valueLiteral) {
-                                createSigletonVariablesAndCollectVariables(valueLiteral.getAtom(), knownVariables, newVariables);
                         }
                 }
                 createVariables(conjunction, newVariables);
diff --git a/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemScopeProvider.java b/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemScopeProvider.java
index 7a3e77a4..925ac3a5 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemScopeProvider.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemScopeProvider.java
@@ -13,10 +13,10 @@ import org.eclipse.xtext.scoping.IScope;
 import org.eclipse.xtext.scoping.Scopes;
 
 import tools.refinery.language.ProblemUtil;
-import tools.refinery.language.model.problem.Action;
 import tools.refinery.language.model.problem.ClassDeclaration;
+import tools.refinery.language.model.problem.Consequent;
 import tools.refinery.language.model.problem.ExistentialQuantifier;
-import tools.refinery.language.model.problem.NewActionLiteral;
+import tools.refinery.language.model.problem.NewAction;
 import tools.refinery.language.model.problem.ParametricDefinition;
 import tools.refinery.language.model.problem.Problem;
 import tools.refinery.language.model.problem.ProblemPackage;
@@ -41,7 +41,8 @@ public class ProblemScopeProvider extends AbstractProblemScopeProvider {
                         return getNodesScope(context, scope);
                 }
                 if (reference == ProblemPackage.Literals.VARIABLE_OR_NODE_ARGUMENT__VARIABLE_OR_NODE
-                                || reference == ProblemPackage.Literals.DELETE_ACTION_LITERAL__VARIABLE_OR_NODE) {
+                                || reference == ProblemPackage.Literals.NEW_ACTION__PARENT
+                                || reference == ProblemPackage.Literals.DELETE_ACTION__VARIABLE_OR_NODE) {
                         return getVariableScope(context, scope);
                 }
                 if (reference == ProblemPackage.Literals.REFERENCE_DECLARATION__OPPOSITE) {
@@ -60,32 +61,39 @@ public class ProblemScopeProvider extends AbstractProblemScopeProvider {
 
         protected IScope getVariableScope(EObject context, IScope delegateScope) {
                 List<Variable> variables = new ArrayList<>();
+                addSingletonVariableToScope(context, variables);
                 EObject currentContext = context;
+                while (currentContext != null && !(currentContext instanceof ParametricDefinition)) {
+                        addExistentiallyQualifiedVariableToScope(currentContext, variables);
+                        currentContext = currentContext.eContainer();
+                }
+                IScope parentScope = getNodesScope(context, delegateScope);
+                if (currentContext != null) {
+                        ParametricDefinition definition = (ParametricDefinition) currentContext;
+                        parentScope = Scopes.scopeFor(definition.getParameters(), parentScope);
+                }
+                return Scopes.scopeFor(variables, parentScope);
+        }
+
+        protected void addSingletonVariableToScope(EObject context, List<Variable> variables) {
                 if (context instanceof VariableOrNodeArgument argument) {
                         Variable singletonVariable = argument.getSingletonVariable();
                         if (singletonVariable != null) {
                                 variables.add(singletonVariable);
                         }
                 }
-                while (currentContext != null && !(currentContext instanceof ParametricDefinition)) {
-                        if (currentContext instanceof ExistentialQuantifier quantifier) {
-                                variables.addAll(quantifier.getImplicitVariables());
-                        } else
-                        if(currentContext instanceof Action action) {
-                                for (var literal : action.getActionLiterals()) {
-                                        if(literal instanceof NewActionLiteral newActionLiteral && newActionLiteral.getVariable() != null) {
-                                                variables.add(newActionLiteral.getVariable());
-                                        }
+        }
+
+        protected void addExistentiallyQualifiedVariableToScope(EObject currentContext, List<Variable> variables) {
+                if (currentContext instanceof ExistentialQuantifier quantifier) {
+                        variables.addAll(quantifier.getImplicitVariables());
+                } else if (currentContext instanceof Consequent consequent) {
+                        for (var literal : consequent.getActions()) {
+                                if (literal instanceof NewAction newAction && newAction.getVariable() != null) {
+                                        variables.add(newAction.getVariable());
                                 }
                         }
-                        currentContext = currentContext.eContainer();
-                }
-                IScope parentScope = getNodesScope(context, delegateScope);
-                if (currentContext != null) {
-                        ParametricDefinition definition = (ParametricDefinition) currentContext;
-                        parentScope = Scopes.scopeFor(definition.getParameters(),parentScope);
                 }
-                return Scopes.scopeFor(variables,parentScope);
         }
 
         protected IScope getOppositeScope(EObject context, IScope delegateScope) {