Basic TensorFlow integration

This wil replace any occurrence of tensorflow(...)
in ranking expressions with the corresponding translated expression.

It is functional but these tings are outstanding
- Propagate warnings
- Import a model just once even if referred multiple times
- Add constants as tensor files rather than config

1 files changed, 66 insertions, 0 deletions

diff --git a/config-model/src/main/java/com/yahoo/searchdefinition/expressiontransforms/MacroShadower.java b/config-model/src/main/java/com/yahoo/searchdefinition/expressiontransforms/MacroShadower.java
new file mode 100644
index 00000000000..1d9769d0d78
--- /dev/null
+++ b/config-model/src/main/java/com/yahoo/searchdefinition/expressiontransforms/MacroShadower.java
@@ -0,0 +1,66 @@
+// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.searchdefinition.expressiontransforms;
+
+import com.yahoo.searchdefinition.RankProfile;
+import com.yahoo.searchlib.rankingexpression.RankingExpression;
+import com.yahoo.searchlib.rankingexpression.rule.*;
+import com.yahoo.searchlib.rankingexpression.transform.ExpressionTransformer;
+
+import java.util.Map;
+
+/**
+ * Transforms function nodes to reference nodes if a macro shadows a built-in function.
+ * This has the effect of allowing macros to redefine built-in functions.
+ * Another effect is that we can more or less add built-in functions over time
+ * without fear of breaking existing users' macros with the same name.
+ *
+ * However, there is a (largish) caveat. If a user has a macro with a certain number
+ * of arguments, and we add in a built-in function with a different arity,
+ * this will cause parse errors as the Java parser gives precedence to
+ * built-in functions.
+ *
+ * @author lesters
+ */
+public class MacroShadower extends ExpressionTransformer {
+
+    private final Map<String, RankProfile.Macro> macros;
+
+    public MacroShadower(Map<String, RankProfile.Macro> macros) {
+        this.macros = macros;
+    }
+
+    @Override
+    public RankingExpression transform(RankingExpression expression) {
+        String name = expression.getName();
+        ExpressionNode node = expression.getRoot();
+        ExpressionNode result = transform(node);
+        return new RankingExpression(name, result);
+    }
+
+    @Override
+    public ExpressionNode transform(ExpressionNode node) {
+        if (node instanceof FunctionNode)
+            return transformFunctionNode((FunctionNode) node);
+        if (node instanceof CompositeNode)
+            return transformChildren((CompositeNode)node);
+        return node;
+    }
+
+    protected ExpressionNode transformFunctionNode(FunctionNode function) {
+        String name = function.getFunction().toString();
+        RankProfile.Macro macro = macros.get(name);
+        if (macro == null) {
+            return transformChildren(function);
+        }
+
+        int functionArity = function.getFunction().arity();
+        int macroArity = macro.getFormalParams() != null ? macro.getFormalParams().size() : 0;
+        if (functionArity != macroArity) {
+            return transformChildren(function);
+        }
+
+        ReferenceNode node = new ReferenceNode(name, function.children(), null);
+        return transformChildren(node);
+    }
+
+}