refactor(language): computed constraint symbol

2 files changed, 10 insertions, 1 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 d6c605cc..5adc50eb 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/Problem.xtext
+++ b/subprojects/language/src/main/java/tools/refinery/language/Problem.xtext
@@ -199,8 +199,8 @@ CastExprBody returns Expr:
         Atom | VariableOrNodeExpr | Constant | "(" Expr ")";
 
 Atom:
-        computed?="computed"?
         relation=[Relation|QualifiedName]
+        computed?="<-"?
         transitiveClosure?=TRANSITIVE_CLOSURE?
         "(" (arguments+=Expr ("," arguments+=Expr)*)? ")";
 
diff --git a/subprojects/language/src/main/java/tools/refinery/language/parser/antlr/ProblemTokenSource.java b/subprojects/language/src/main/java/tools/refinery/language/parser/antlr/ProblemTokenSource.java
index 487e4ceb..e483517a 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/parser/antlr/ProblemTokenSource.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/parser/antlr/ProblemTokenSource.java
@@ -28,6 +28,8 @@ public class ProblemTokenSource implements TokenSource {
 
         private boolean seenId;
 
+        private boolean seenComputed;
+
         private boolean lastVisible;
 
         public ProblemTokenSource(TokenSource delegate) {
@@ -57,10 +59,13 @@ public class ProblemTokenSource implements TokenSource {
                         } else if (lastVisible && isQualifiedNameSeparator(token)) {
                                 token.setType(InternalProblemParser.RULE_QUALIFIED_NAME_SEPARATOR);
                         }
+                } else if (seenComputed && isPlusOrTransitiveClosure(token) && peekForTransitiveClosure()) {
+                        token.setType(InternalProblemParser.RULE_TRANSITIVE_CLOSURE);
                 }
                 lastVisible = isVisibleToken(token);
                 if (lastVisible) {
                         seenId = isIdentifier(token);
+                        seenComputed = isComputed(token);
                 }
                 return token;
         }
@@ -82,6 +87,10 @@ public class ProblemTokenSource implements TokenSource {
                 return token.getType() == InternalProblemParser.ColonColon;
         }
 
+        protected boolean isComputed(Token token) {
+                return token.getType() == InternalProblemParser.LessThanSignHyphenMinus;
+        }
+
         protected boolean isVisibleToken(Token token) {
                 int tokenId = token.getType();
                 return tokenId != InternalProblemParser.RULE_WS && tokenId != InternalProblemParser.RULE_SL_COMMENT &&