SQL: Internal refactoring of operators as functions (#34097)

Centralize and simplify the script generation between operators and functions which are currently decoupled. As part of this process most predicates (<, <=, etc...) were made ScalarFunction as their purpose and functionality is quite similar (see % and MOD functions).
Renamed ProcessDefinition to Pipe
Add ScriptWeaver as a mixin-in interface for script customization
Add logic for equals/lte/lt
Improve BinaryOperator/expression toString
Minimize duplication across string functions

Close #33975

Author: costin

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/analysis/analyzer/Analyzer.java

@@ -29,7 +29,7 @@
 import org.elasticsearch.xpack.sql.expression.function.Functions;
 import org.elasticsearch.xpack.sql.expression.function.UnresolvedFunction;
 import org.elasticsearch.xpack.sql.expression.function.scalar.Cast;
-import org.elasticsearch.xpack.sql.expression.function.scalar.arithmetic.ArithmeticFunction;
+import org.elasticsearch.xpack.sql.expression.predicate.operator.arithmetic.ArithmeticOperation;
 import org.elasticsearch.xpack.sql.plan.TableIdentifier;
 import org.elasticsearch.xpack.sql.plan.logical.Aggregate;
 import org.elasticsearch.xpack.sql.plan.logical.EsRelation;
@@ -1007,8 +1007,8 @@ private Expression implicitCast(Expression e) {
             // BinaryOperations are ignored as they are pushed down to ES
             // and casting (and thus Aliasing when folding) gets in the way
 
-            if (e instanceof ArithmeticFunction) {
-                ArithmeticFunction f = (ArithmeticFunction) e;
+            if (e instanceof ArithmeticOperation) {
+                ArithmeticOperation f = (ArithmeticOperation) e;
                 left = f.left();
                 right = f.right();
             }

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/execution/search/Querier.java

@@ -32,11 +32,11 @@
 import org.elasticsearch.xpack.sql.execution.search.extractor.FieldHitExtractor;
 import org.elasticsearch.xpack.sql.execution.search.extractor.HitExtractor;
 import org.elasticsearch.xpack.sql.execution.search.extractor.MetricAggExtractor;
-import org.elasticsearch.xpack.sql.expression.function.scalar.processor.definition.AggExtractorInput;
-import org.elasticsearch.xpack.sql.expression.function.scalar.processor.definition.AggPathInput;
-import org.elasticsearch.xpack.sql.expression.function.scalar.processor.definition.HitExtractorInput;
-import org.elasticsearch.xpack.sql.expression.function.scalar.processor.definition.ProcessorDefinition;
-import org.elasticsearch.xpack.sql.expression.function.scalar.processor.definition.ReferenceInput;
+import org.elasticsearch.xpack.sql.expression.gen.pipeline.AggExtractorInput;
+import org.elasticsearch.xpack.sql.expression.gen.pipeline.AggPathInput;
+import org.elasticsearch.xpack.sql.expression.gen.pipeline.HitExtractorInput;
+import org.elasticsearch.xpack.sql.expression.gen.pipeline.Pipe;
+import org.elasticsearch.xpack.sql.expression.gen.pipeline.ReferenceInput;
 import org.elasticsearch.xpack.sql.querydsl.agg.Aggs;
 import org.elasticsearch.xpack.sql.querydsl.container.ComputedRef;
 import org.elasticsearch.xpack.sql.querydsl.container.GlobalCountRef;
@@ -275,7 +275,7 @@ private BucketExtractor createExtractor(FieldExtraction ref, BucketExtractor tot
             }
 
             if (ref instanceof ComputedRef) {
-                ProcessorDefinition proc = ((ComputedRef) ref).processor();
+                Pipe proc = ((ComputedRef) ref).processor();
 
                 // wrap only agg inputs
                 proc = proc.transformDown(l -> {
@@ -351,7 +351,7 @@ private HitExtractor createExtractor(FieldExtraction ref) {
             }
 
             if (ref instanceof ComputedRef) {
-                ProcessorDefinition proc = ((ComputedRef) ref).processor();
+                Pipe proc = ((ComputedRef) ref).processor();
                 // collect hitNames
                 Set<String> hitNames = new LinkedHashSet<>();
                 proc = proc.transformDown(l -> {

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/execution/search/extractor/ComputingExtractor.java

@@ -9,8 +9,8 @@
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.search.SearchHit;
 import org.elasticsearch.search.aggregations.bucket.MultiBucketsAggregation.Bucket;
-import org.elasticsearch.xpack.sql.expression.function.scalar.processor.runtime.HitExtractorProcessor;
-import org.elasticsearch.xpack.sql.expression.function.scalar.processor.runtime.Processor;
+import org.elasticsearch.xpack.sql.expression.gen.processor.HitExtractorProcessor;
+import org.elasticsearch.xpack.sql.expression.gen.processor.Processor;
 
 import java.io.IOException;
 import java.util.Objects;

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/expression/Alias.java

@@ -5,16 +5,18 @@
  */
 package org.elasticsearch.xpack.sql.expression;
 
+import org.elasticsearch.xpack.sql.SqlIllegalArgumentException;
+import org.elasticsearch.xpack.sql.expression.gen.script.ScriptTemplate;
 import org.elasticsearch.xpack.sql.tree.Location;
 import org.elasticsearch.xpack.sql.tree.NodeInfo;
 import org.elasticsearch.xpack.sql.type.DataType;
 import org.elasticsearch.xpack.sql.type.EsField;
 
-import static java.util.Collections.singletonList;
-
 import java.util.Collections;
 import java.util.List;
 
+import static java.util.Collections.singletonList;
+
 /**
  * An {@code Alias} is a {@code NamedExpression} that gets renamed to something else through the Alias.
  *
@@ -91,6 +93,11 @@ public Attribute toAttribute() {
         return lazyAttribute;
     }
 
+    @Override
+    public ScriptTemplate asScript() {
+        throw new SqlIllegalArgumentException("Encountered a bug; an alias should never be scripted");
+    }
+
     private Attribute createAttribute() {
         if (resolved()) {
             Expression c = child();
@@ -114,4 +121,4 @@ private Attribute createAttribute() {
     public String toString() {
         return child + " AS " + name() + "#" + id();
     }
-}
+}

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/expression/Attribute.java

@@ -5,7 +5,10 @@
  */
 package org.elasticsearch.xpack.sql.expression;
 
+import org.elasticsearch.xpack.sql.SqlIllegalArgumentException;
+import org.elasticsearch.xpack.sql.expression.gen.script.ScriptTemplate;
 import org.elasticsearch.xpack.sql.tree.Location;
+import org.elasticsearch.xpack.sql.tree.NodeInfo;
 
 import java.util.List;
 import java.util.Objects;
@@ -60,6 +63,11 @@ public final Expression replaceChildren(List<Expression> newChildren) {
         throw new UnsupportedOperationException("this type of node doesn't have any children to replace");
     }
 
+    @Override
+    public ScriptTemplate asScript() {
+        throw new SqlIllegalArgumentException("Encountered a bug - an attribute should never be scripted");
+    }
+
     public String qualifier() {
         return qualifier;
     }
@@ -103,6 +111,11 @@ public int semanticHash() {
         return id().hashCode();
     }
 
+    @Override
+    protected NodeInfo<? extends Expression> info() {
+        return null;
+    }
+
     @Override
     public boolean semanticEquals(Expression other) {
         return other instanceof Attribute ? id().equals(((Attribute) other).id()) : false;
@@ -130,4 +143,4 @@ public String toString() {
     }
 
     protected abstract String label();
-}
+}

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/expression/BinaryExpression.java

@@ -132,4 +132,4 @@ public boolean resolved() {
     public String toString() {
         return nodeName() + "[" + propertiesToString(false) + "]";
     }
-}
+}

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/expression/Expression.java

@@ -5,7 +5,9 @@
  */
 package org.elasticsearch.xpack.sql.expression;
 
+import org.elasticsearch.xpack.sql.SqlIllegalArgumentException;
 import org.elasticsearch.xpack.sql.expression.Expression.TypeResolution;
+import org.elasticsearch.xpack.sql.expression.gen.pipeline.Pipe;
 
 import java.util.ArrayList;
 import java.util.Collection;
@@ -112,6 +114,13 @@ public static boolean equalsAsAttribute(Expression left, Expression right) {
         return true;
     }
 
+    public static Pipe pipe(Expression e) {
+        if (e instanceof NamedExpression) {
+            return ((NamedExpression) e).asPipe();
+        }
+        throw new SqlIllegalArgumentException("Cannot create pipe for {}", e);
+    }
+
     public static TypeResolution typeMustBe(Expression e, Predicate<Expression> predicate, String message) {
         return predicate.test(e) ? TypeResolution.TYPE_RESOLVED : new TypeResolution(message);
     }

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/expression/Expressions.java

@@ -6,6 +6,8 @@
 package org.elasticsearch.xpack.sql.expression;
 
 import org.elasticsearch.xpack.sql.SqlIllegalArgumentException;
+import org.elasticsearch.xpack.sql.expression.gen.script.Params;
+import org.elasticsearch.xpack.sql.expression.gen.script.ScriptTemplate;
 import org.elasticsearch.xpack.sql.tree.Location;
 import org.elasticsearch.xpack.sql.tree.NodeInfo;
 import org.elasticsearch.xpack.sql.type.DataType;
@@ -77,6 +79,11 @@ public Attribute toAttribute() {
         return new LiteralAttribute(location(), name(), null, false, id(), false, dataType, this);
     }
 
+    @Override
+    public ScriptTemplate asScript() {
+        return new ScriptTemplate(String.valueOf(value), Params.EMPTY, dataType);
+    }
+
     @Override
     public Expression replaceChildren(List<Expression> newChildren) {
         throw new UnsupportedOperationException("this type of node doesn't have any children to replace");
@@ -87,9 +94,15 @@ public AttributeSet references() {
         return AttributeSet.EMPTY;
     }
 
+    @Override
+    protected Expression canonicalize() {
+        String s = String.valueOf(value);
+        return name().equals(s) ? this : Literal.of(location(), value);
+    }
+
     @Override
     public int hashCode() {
-        return Objects.hash(name(), value, dataType);
+        return Objects.hash(value, dataType);
     }
 
     @Override
@@ -102,8 +115,7 @@ public boolean equals(Object obj) {
         }
 
         Literal other = (Literal) obj;
-        return Objects.equals(name(), other.name())
-                && Objects.equals(value, other.value)
+        return Objects.equals(value, other.value)
                 && Objects.equals(dataType, other.dataType);
     }
 

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/expression/Literal.java

@@ -5,8 +5,7 @@
  */
 package org.elasticsearch.xpack.sql.expression;
 
-import org.elasticsearch.xpack.sql.expression.function.scalar.processor.definition.ConstantInput;
-import org.elasticsearch.xpack.sql.expression.function.scalar.processor.definition.ProcessorDefinition;
+import org.elasticsearch.xpack.sql.expression.gen.pipeline.Pipe;
 import org.elasticsearch.xpack.sql.tree.Location;
 import org.elasticsearch.xpack.sql.tree.NodeInfo;
 import org.elasticsearch.xpack.sql.type.DataType;
@@ -33,12 +32,13 @@ protected LiteralAttribute clone(Location location, String name, String qualifie
         return new LiteralAttribute(location, name, qualifier, nullable, id, synthetic, dataType(), literal);
     }
 
-    public ProcessorDefinition asProcessorDefinition() {
-        return new ConstantInput(location(), literal, literal.value());
-    }
-
     @Override
     protected String label() {
         return "c";
     }
+
+    @Override
+    public Pipe asPipe() {
+        return literal.asPipe();
+    }
 }