SQL: fix name of Arithmetic functions (elastic/x-pack-elasticsearch#3884)

* SQL: fix name of Arithmetic functions

Remove id from name of Arithmetic function and improve name of Neg

Original commit: elastic/x-pack-elasticsearch@4f3e8d6a2d

plugin/sql/src/main/java/org/elasticsearch/xpack/sql/expression/function/scalar/arithmetic/ArithmeticFunction.java

@@ -82,11 +82,6 @@ public abstract class ArithmeticFunction extends BinaryScalarFunction {
 
     @Override
     public String name() {
-        return toString();
-    }
-
-    @Override
-    public String toString() {
         StringBuilder sb = new StringBuilder();
         sb.append("(");
         sb.append(left());
@@ -103,11 +98,15 @@ public abstract class ArithmeticFunction extends BinaryScalarFunction {
             sb.insert(pos, "(");
             sb.append(")");
         }
-        sb.append(")#");
+        sb.append(")");
-        sb.append(functionId());
         return sb.toString();
     }
 
+    @Override
+    public String toString() {
+        return name() + "#" + functionId();
+    }
+
     protected boolean useParanthesis() {
         return !(left() instanceof Literal) || !(right() instanceof Literal);
     }

plugin/sql/src/main/java/org/elasticsearch/xpack/sql/expression/function/scalar/arithmetic/Neg.java

@@ -7,6 +7,7 @@ package org.elasticsearch.xpack.sql.expression.function.scalar.arithmetic;
 
 import org.elasticsearch.xpack.sql.expression.Expression;
 import org.elasticsearch.xpack.sql.expression.Expressions;
+import org.elasticsearch.xpack.sql.expression.NamedExpression;
 import org.elasticsearch.xpack.sql.expression.function.scalar.UnaryScalarFunction;
 import org.elasticsearch.xpack.sql.expression.function.scalar.arithmetic.UnaryArithmeticProcessor.UnaryArithmeticOperation;
 import org.elasticsearch.xpack.sql.expression.function.scalar.processor.definition.ProcessorDefinition;
@@ -49,6 +50,11 @@ public class Neg extends UnaryScalarFunction {
         return field().dataType();
     }
 
+    @Override
+    public String name() {
+        return "-" + (field() instanceof NamedExpression && field().resolved() ? Expressions.name(field()) : field().toString());
+    }
+
     @Override
     protected String formatScript(String template) {
         // Painless supports negating (and hopefully its corner cases)

plugin/sql/src/test/java/org/elasticsearch/xpack/sql/expression/function/NamedExpressionTests.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+package org.elasticsearch.xpack.sql.expression.function;
+
+import org.elasticsearch.test.ESTestCase;
+import org.elasticsearch.xpack.sql.expression.Literal;
+import org.elasticsearch.xpack.sql.expression.function.scalar.arithmetic.Add;
+import org.elasticsearch.xpack.sql.expression.function.scalar.arithmetic.Div;
+import org.elasticsearch.xpack.sql.expression.function.scalar.arithmetic.Mod;
+import org.elasticsearch.xpack.sql.expression.function.scalar.arithmetic.Mul;
+import org.elasticsearch.xpack.sql.expression.function.scalar.arithmetic.Neg;
+import org.elasticsearch.xpack.sql.expression.function.scalar.arithmetic.Sub;
+
+import static org.elasticsearch.xpack.sql.tree.Location.EMPTY;
+
+public class NamedExpressionTests extends ESTestCase {
+
+    public void testArithmeticFunctionName() {
+        Add add = new Add(EMPTY, l(5), l(2));
+        assertEquals("(5 + 2)", add.name());
+
+        Div div = new Div(EMPTY, l(5), l(2));
+        assertEquals("(5 / 2)", div.name());
+
+        Mod mod = new Mod(EMPTY, l(5), l(2));
+        assertEquals("(5 % 2)", mod.name());
+
+        Mul mul = new Mul(EMPTY, l(5), l(2));
+        assertEquals("(5 * 2)", mul.name());
+
+        Sub sub = new Sub(EMPTY, l(5), l(2));
+        assertEquals("(5 - 2)", sub.name());
+
+        Neg neg = new Neg(EMPTY, l(5));
+        assertEquals("-5", neg.name());
+    }
+
+    private static Literal l(Object value) {
+        return Literal.of(EMPTY, value);
+    }
+}