Use LP RP instead

Author: luigidellaquila

x-pack/plugin/esql/src/main/antlr/EsqlBaseParser.g4

@@ -240,7 +240,7 @@ explainCommand
     ;
 
 subqueryExpression
-    : OPENING_BRACKET query CLOSING_BRACKET
+    : LP query RP
     ;
 
 showCommand

x-pack/plugin/esql/src/main/antlr/lexer/Explain.g4

@@ -11,10 +11,10 @@ lexer grammar Explain;
 //
 EXPLAIN : 'explain'           -> pushMode(EXPLAIN_MODE);
 
-
 mode EXPLAIN_MODE;
-EXPLAIN_OPENING_BRACKET : OPENING_BRACKET -> type(OPENING_BRACKET), pushMode(DEFAULT_MODE);
+EXPLAIN_LP : LP -> type(LP), pushMode(DEFAULT_MODE);
 EXPLAIN_PIPE : PIPE -> type(PIPE), popMode;
+
 EXPLAIN_WS : WS -> channel(HIDDEN);
 EXPLAIN_LINE_COMMENT : LINE_COMMENT -> channel(HIDDEN);
 EXPLAIN_MULTILINE_COMMENT : MULTILINE_COMMENT -> channel(HIDDEN);

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/parser/EsqlBaseLexer.interp

@@ -44,7 +44,7 @@ explainRow:
         - "No limit defined, adding default limit of \\[.*\\]"
       esql.query:
         body:
-          query: 'EXPLAIN [row a = 1]'
+          query: 'EXPLAIN (row a = 1)'
 
   - length: { columns: 3 }
   - length: { values: 1 }
@@ -63,7 +63,7 @@ explainQuery:
         - "No limit defined, adding default limit of \\[.*\\]"
       esql.query:
         body:
-          query: 'EXPLAIN [from test | where color == "red" | eval b = 20]'
+          query: 'EXPLAIN (from test | where color == "red" | eval b = 20)'
 
   - length: { columns: 3 }
   - length: { values: 1 }
@@ -82,7 +82,7 @@ explainDownstream:
         - "No limit defined, adding default limit of \\[.*\\]"
       esql.query:
         body:
-          query: 'EXPLAIN [row a = 1] | eval b = 2'
+          query: 'EXPLAIN (row a = 1) | eval b = 2'
       catch: "bad_request"
 
   - match: { error.type: "verification_exception" }