EQL: Add AstBuilder to convert to QL tree

x-pack/plugin/eql/src/main/antlr/EqlBase.g4

@@ -73,32 +73,27 @@ expression
 booleanExpression
     : NOT booleanExpression                                               #logicalNot
     | relationship=IDENTIFIER OF subquery                                 #processCheck
-    | predicated                                                          #booleanDefault
+    | valueExpression                                                     #booleanDefault
     | left=booleanExpression operator=AND right=booleanExpression         #logicalBinary
     | left=booleanExpression operator=OR right=booleanExpression          #logicalBinary
     ;
 
-// workaround for:
-//  https://github.com/antlr/antlr4/issues/780
-//  https://github.com/antlr/antlr4/issues/781
-predicated
-    : valueExpression predicate?
-    ;
-
-// dedicated calls for each branch are not used to reuse the NOT handling across them
-// instead the property kind is used for differentiation
-predicate
-    : NOT? kind=IN LP valueExpression (COMMA valueExpression)* RP
-    ;
 
 valueExpression
-    : primaryExpression                                                                 #valueExpressionDefault
+    : primaryExpression predicate?                                                      #valueExpressionDefault
     | operator=(MINUS | PLUS) valueExpression                                           #arithmeticUnary
     | left=valueExpression operator=(ASTERISK | SLASH | PERCENT) right=valueExpression  #arithmeticBinary
     | left=valueExpression operator=(PLUS | MINUS) right=valueExpression                #arithmeticBinary
     | left=valueExpression comparisonOperator right=valueExpression                     #comparison
     ;
 
+// workaround for
+//   https://github.com/antlr/antlr4/issues/780
+//   https://github.com/antlr/antlr4/issues/781
+predicate
+    : NOT? kind=IN LP expression (COMMA expression)* RP
+    ;
+
 primaryExpression
     : constant                                                                          #constantDefault
     | functionExpression                                                                #function

x-pack/plugin/eql/src/main/java/org/elasticsearch/xpack/eql/parser/AbstractBuilder.java

@@ -10,7 +10,7 @@
 import org.antlr.v4.runtime.misc.Interval;
 import org.antlr.v4.runtime.tree.ParseTree;
 import org.antlr.v4.runtime.tree.TerminalNode;
-import org.elasticsearch.xpack.ql.expression.Expression;
+import org.elasticsearch.xpack.ql.plan.logical.LogicalPlan;
 import org.elasticsearch.xpack.ql.tree.Location;
 import org.elasticsearch.xpack.ql.tree.Source;
 import org.elasticsearch.xpack.ql.util.Check;
@@ -25,6 +25,8 @@
  */
 abstract class AbstractBuilder extends EqlBaseBaseVisitor<Object> {
 
+    private static final Pattern slashPattern = Pattern.compile("\\\\.");
+
     @Override
     public Object visit(ParseTree tree) {
         Object result = super.visit(tree);
@@ -44,12 +46,12 @@ protected <T> T typedParsing(ParseTree ctx, Class<T> type) {
                         type.getSimpleName(), (result != null ? result.getClass().getSimpleName() : "null"));
     }
 
-    protected Expression expression(ParseTree ctx) {
-        return typedParsing(ctx, Expression.class);
+    protected LogicalPlan plan(ParseTree ctx) {
+        return typedParsing(ctx, LogicalPlan.class);
     }
 
-    protected List<Expression> expressions(List<? extends ParserRuleContext> ctxs) {
-        return visitList(ctxs, Expression.class);
+    protected List<LogicalPlan> plans(List<? extends ParserRuleContext> ctxs) {
+        return visitList(ctxs, LogicalPlan.class);
     }
 
     protected <T> List<T> visitList(List<? extends ParserRuleContext> contexts, Class<T> clazz) {
@@ -113,14 +115,7 @@ static String text(ParseTree node) {
         return node == null ? null : node.getText();
     }
 
-    /**
-     * Extracts the actual unescaped string (literal) value of a terminal node.
-     */
-    static String string(TerminalNode node) {
-        return node == null ? null : unquoteString(node.getText());
-    }
-
-    static String unquoteString(String text) {
+    public static String unquoteString(String text) {
         // remove leading and trailing ' for strings and also eliminate escaped single quotes
         if (text == null) {
             return null;
@@ -132,9 +127,8 @@ static String unquoteString(String text) {
         }
 
         text = text.substring(1, text.length() - 1);
-        Pattern regex = Pattern.compile("\\\\.");
         StringBuffer resultString = new StringBuffer();
-        Matcher regexMatcher = regex.matcher(text);
+        Matcher regexMatcher = slashPattern.matcher(text);
 
         while (regexMatcher.find()) {
             String source = regexMatcher.group();
@@ -167,6 +161,7 @@ static String unquoteString(String text) {
                     replacement = "\\\\";
                     break;
                 default:
+                    // unknown escape sequence, pass through as-is
                     replacement = source;
             }
 
@@ -183,4 +178,5 @@ public Object visitTerminal(TerminalNode node) {
         Source source = source(node);
         throw new ParsingException(source, "Does not know how to handle {}", source.text());
     }
+
 }

x-pack/plugin/eql/src/main/java/org/elasticsearch/xpack/eql/parser/AstBuilder.java

@@ -7,11 +7,12 @@
 package org.elasticsearch.xpack.eql.parser;
 
 import org.elasticsearch.xpack.eql.parser.EqlBaseParser.SingleStatementContext;
+import org.elasticsearch.xpack.ql.plan.logical.LogicalPlan;
 
-public class AstBuilder extends ExpressionBuilder {
+public class AstBuilder extends LogicalPlanBuilder {
 
     @Override
-    public Object visitSingleStatement(SingleStatementContext ctx) {
-        return expression(ctx.statement());
+    public LogicalPlan visitSingleStatement(SingleStatementContext ctx) {
+        return plan(ctx.statement());
     }
-}
+}

x-pack/plugin/eql/src/main/java/org/elasticsearch/xpack/eql/parser/EqlBaseBaseListener.java

@@ -232,73 +232,61 @@ class EqlBaseBaseListener implements EqlBaseListener {
    *
    * <p>The default implementation does nothing.</p>
    */
-  @Override public void enterPredicated(EqlBaseParser.PredicatedContext ctx) { }
-  /**
-   * {@inheritDoc}
-   *
-   * <p>The default implementation does nothing.</p>
-   */
-  @Override public void exitPredicated(EqlBaseParser.PredicatedContext ctx) { }
-  /**
-   * {@inheritDoc}
-   *
-   * <p>The default implementation does nothing.</p>
-   */
-  @Override public void enterPredicate(EqlBaseParser.PredicateContext ctx) { }
+  @Override public void enterValueExpressionDefault(EqlBaseParser.ValueExpressionDefaultContext ctx) { }
   /**
    * {@inheritDoc}
    *
    * <p>The default implementation does nothing.</p>
    */
-  @Override public void exitPredicate(EqlBaseParser.PredicateContext ctx) { }
+  @Override public void exitValueExpressionDefault(EqlBaseParser.ValueExpressionDefaultContext ctx) { }
   /**
    * {@inheritDoc}
    *
    * <p>The default implementation does nothing.</p>
    */
-  @Override public void enterValueExpressionDefault(EqlBaseParser.ValueExpressionDefaultContext ctx) { }
+  @Override public void enterComparison(EqlBaseParser.ComparisonContext ctx) { }
   /**
    * {@inheritDoc}
    *
    * <p>The default implementation does nothing.</p>
    */
-  @Override public void exitValueExpressionDefault(EqlBaseParser.ValueExpressionDefaultContext ctx) { }
+  @Override public void exitComparison(EqlBaseParser.ComparisonContext ctx) { }
   /**
    * {@inheritDoc}
    *
    * <p>The default implementation does nothing.</p>
    */
-  @Override public void enterComparison(EqlBaseParser.ComparisonContext ctx) { }
+  @Override public void enterArithmeticBinary(EqlBaseParser.ArithmeticBinaryContext ctx) { }
   /**
    * {@inheritDoc}
    *
    * <p>The default implementation does nothing.</p>
    */
-  @Override public void exitComparison(EqlBaseParser.ComparisonContext ctx) { }
+  @Override public void exitArithmeticBinary(EqlBaseParser.ArithmeticBinaryContext ctx) { }
   /**
    * {@inheritDoc}
    *
    * <p>The default implementation does nothing.</p>
    */
-  @Override public void enterArithmeticBinary(EqlBaseParser.ArithmeticBinaryContext ctx) { }
+  @Override public void enterArithmeticUnary(EqlBaseParser.ArithmeticUnaryContext ctx) { }
   /**
    * {@inheritDoc}
    *
    * <p>The default implementation does nothing.</p>
    */
-  @Override public void exitArithmeticBinary(EqlBaseParser.ArithmeticBinaryContext ctx) { }
+  @Override public void exitArithmeticUnary(EqlBaseParser.ArithmeticUnaryContext ctx) { }
   /**
    * {@inheritDoc}
    *
    * <p>The default implementation does nothing.</p>
    */
-  @Override public void enterArithmeticUnary(EqlBaseParser.ArithmeticUnaryContext ctx) { }
+  @Override public void enterPredicate(EqlBaseParser.PredicateContext ctx) { }
   /**
    * {@inheritDoc}
    *
    * <p>The default implementation does nothing.</p>
    */
-  @Override public void exitArithmeticUnary(EqlBaseParser.ArithmeticUnaryContext ctx) { }
+  @Override public void exitPredicate(EqlBaseParser.PredicateContext ctx) { }
   /**
    * {@inheritDoc}
    *

x-pack/plugin/eql/src/main/java/org/elasticsearch/xpack/eql/parser/EqlBaseBaseVisitor.java

@@ -143,42 +143,35 @@ class EqlBaseBaseVisitor<T> extends AbstractParseTreeVisitor<T> implements EqlBa
    * <p>The default implementation returns the result of calling
    * {@link #visitChildren} on {@code ctx}.</p>
    */
-  @Override public T visitPredicated(EqlBaseParser.PredicatedContext ctx) { return visitChildren(ctx); }
-  /**
-   * {@inheritDoc}
-   *
-   * <p>The default implementation returns the result of calling
-   * {@link #visitChildren} on {@code ctx}.</p>
-   */
-  @Override public T visitPredicate(EqlBaseParser.PredicateContext ctx) { return visitChildren(ctx); }
+  @Override public T visitValueExpressionDefault(EqlBaseParser.ValueExpressionDefaultContext ctx) { return visitChildren(ctx); }
   /**
    * {@inheritDoc}
    *
    * <p>The default implementation returns the result of calling
    * {@link #visitChildren} on {@code ctx}.</p>
    */
-  @Override public T visitValueExpressionDefault(EqlBaseParser.ValueExpressionDefaultContext ctx) { return visitChildren(ctx); }
+  @Override public T visitComparison(EqlBaseParser.ComparisonContext ctx) { return visitChildren(ctx); }
   /**
    * {@inheritDoc}
    *
    * <p>The default implementation returns the result of calling
    * {@link #visitChildren} on {@code ctx}.</p>
    */
-  @Override public T visitComparison(EqlBaseParser.ComparisonContext ctx) { return visitChildren(ctx); }
+  @Override public T visitArithmeticBinary(EqlBaseParser.ArithmeticBinaryContext ctx) { return visitChildren(ctx); }
   /**
    * {@inheritDoc}
    *
    * <p>The default implementation returns the result of calling
    * {@link #visitChildren} on {@code ctx}.</p>
    */
-  @Override public T visitArithmeticBinary(EqlBaseParser.ArithmeticBinaryContext ctx) { return visitChildren(ctx); }
+  @Override public T visitArithmeticUnary(EqlBaseParser.ArithmeticUnaryContext ctx) { return visitChildren(ctx); }
   /**
    * {@inheritDoc}
    *
    * <p>The default implementation returns the result of calling
    * {@link #visitChildren} on {@code ctx}.</p>
    */
-  @Override public T visitArithmeticUnary(EqlBaseParser.ArithmeticUnaryContext ctx) { return visitChildren(ctx); }
+  @Override public T visitPredicate(EqlBaseParser.PredicateContext ctx) { return visitChildren(ctx); }
   /**
    * {@inheritDoc}
    *

x-pack/plugin/eql/src/main/java/org/elasticsearch/xpack/eql/parser/EqlBaseListener.java

@@ -195,26 +195,6 @@ interface EqlBaseListener extends ParseTreeListener {
    * @param ctx the parse tree
    */
   void exitLogicalBinary(EqlBaseParser.LogicalBinaryContext ctx);
-  /**
-   * Enter a parse tree produced by {@link EqlBaseParser#predicated}.
-   * @param ctx the parse tree
-   */
-  void enterPredicated(EqlBaseParser.PredicatedContext ctx);
-  /**
-   * Exit a parse tree produced by {@link EqlBaseParser#predicated}.
-   * @param ctx the parse tree
-   */
-  void exitPredicated(EqlBaseParser.PredicatedContext ctx);
-  /**
-   * Enter a parse tree produced by {@link EqlBaseParser#predicate}.
-   * @param ctx the parse tree
-   */
-  void enterPredicate(EqlBaseParser.PredicateContext ctx);
-  /**
-   * Exit a parse tree produced by {@link EqlBaseParser#predicate}.
-   * @param ctx the parse tree
-   */
-  void exitPredicate(EqlBaseParser.PredicateContext ctx);
   /**
    * Enter a parse tree produced by the {@code valueExpressionDefault}
    * labeled alternative in {@link EqlBaseParser#valueExpression}.
@@ -263,6 +243,16 @@ interface EqlBaseListener extends ParseTreeListener {
    * @param ctx the parse tree
    */
   void exitArithmeticUnary(EqlBaseParser.ArithmeticUnaryContext ctx);
+  /**
+   * Enter a parse tree produced by {@link EqlBaseParser#predicate}.
+   * @param ctx the parse tree
+   */
+  void enterPredicate(EqlBaseParser.PredicateContext ctx);
+  /**
+   * Exit a parse tree produced by {@link EqlBaseParser#predicate}.
+   * @param ctx the parse tree
+   */
+  void exitPredicate(EqlBaseParser.PredicateContext ctx);
   /**
    * Enter a parse tree produced by the {@code constantDefault}
    * labeled alternative in {@link EqlBaseParser#primaryExpression}.