Allow expressions as arguments to functions

1 files changed, 13 insertions, 3 deletions

diff --git a/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/ExpressionFunction.java b/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/ExpressionFunction.java
index b97c8316c9b..3974ca7ed0d 100755
--- a/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/ExpressionFunction.java
+++ b/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/ExpressionFunction.java
@@ -6,6 +6,8 @@ import com.google.common.collect.ImmutableMap;
 import com.yahoo.searchlib.rankingexpression.rule.ConstantNode;
 import com.yahoo.searchlib.rankingexpression.rule.ExpressionNode;
 import com.yahoo.searchlib.rankingexpression.rule.FunctionNode;
+import com.yahoo.searchlib.rankingexpression.rule.NameNode;
+import com.yahoo.searchlib.rankingexpression.rule.NegativeNode;
 import com.yahoo.searchlib.rankingexpression.rule.ReferenceNode;
 import com.yahoo.searchlib.rankingexpression.rule.SerializationContext;
 import com.yahoo.tensor.TensorType;
@@ -138,10 +140,10 @@ public class ExpressionFunction {
             ExpressionNode expr = argumentValues.get(i);
             String binding = expr.toString(new StringBuilder(), context, path, null).toString();
 
-            if ( ! (expr instanceof ReferenceNode) && ! (expr instanceof ConstantNode) && ! (expr instanceof FunctionNode) ) {
+            if (shouldGenerateFeature(expr)) {
                 String funcName = "autogenerated_ranking_feature@" + Long.toHexString(symbolCode(key + "=" + binding));
                 context.addFunctionSerialization(RankingExpression.propertyName(funcName), binding);
-                binding = funcName;
+                binding = "rankingExpression(" + funcName + ")";
             }
             argumentBindings.put(key, binding);
         }
@@ -151,6 +153,15 @@ public class ExpressionFunction {
         return new Instance(symbol, expressionString);
     }
 
+    private boolean shouldGenerateFeature(ExpressionNode expr) {
+        if (expr instanceof ConstantNode) return false;
+        if (expr instanceof ReferenceNode) return false;
+        if (expr instanceof NameNode) return false;
+        if (expr instanceof FunctionNode) return false;
+        if (expr instanceof NegativeNode && ((NegativeNode) expr).getValue() instanceof ConstantNode) return false;
+        return true;
+    }
+
     /**
      * Returns a symbolic string that represents this function with a given
      * list of arguments. The arguments are mangled by hashing the string
@@ -173,7 +184,6 @@ public class ExpressionFunction {
         return ret.toString();
     }
 
-
     /**
      * Returns a more unique hash code than what Java's own {@link
      * String#hashCode()} method would produce.