Implement jsonpath unary operations output

Author: Nikita Glukhov

src/backend/utils/adt/jsonpath.c

@@ -259,8 +259,11 @@ operationPriority(JsonPathItemType op)
 		case jpiDiv:
 		case jpiMod:
 			return 4;
-		default:
+		case jpiPlus:
+		case jpiMinus:
 			return 5;
+		default:
+			return 6;
 	}
 }
 
@@ -327,6 +330,18 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey, bool printBracket
 			if (printBracketes)
 				appendStringInfoChar(buf, ')');
 			break;
+		case jpiPlus:
+		case jpiMinus:
+			if (printBracketes)
+				appendStringInfoChar(buf, '(');
+			appendStringInfoChar(buf, v->type == jpiPlus ? '+' : '-');
+			jspGetArg(v, &elem);
+			printJsonPathItem(buf, &elem, false,
+							  operationPriority(elem.type) <=
+							  operationPriority(v->type));
+			if (printBracketes)
+				appendStringInfoChar(buf, ')');
+			break;
 		case jpiFilter:
 			appendBinaryStringInfo(buf, "?(", 2);
 			jspGetArg(v, &elem);

src/test/regress/expected/jsonpath.out

@@ -267,6 +267,12 @@ select '$.g ? ((x >= 123 || a == 4) && exists (.x ? (@ == 14)))'::jsonpath;
  $."g"?(("x" >= 123 || "a" == 4) && exists (@."x"?(@ == 14)))
 (1 row)
 
+select '$.g ? (+x >= +-(+a + 2))'::jsonpath;
+            jsonpath            
+--------------------------------
+ $."g"?(+"x" >= +(-(+"a" + 2)))
+(1 row)
+
 select '$a'::jsonpath;
  jsonpath 
 ----------

src/test/regress/sql/jsonpath.sql

@@ -46,6 +46,7 @@ select '$.g ? (exists (.x))'::jsonpath;
 select '$.g ? (exists (@.x ? (@ == 14)))'::jsonpath;
 select '$.g ? (exists (.x ? (@ == 14)))'::jsonpath;
 select '$.g ? ((x >= 123 || a == 4) && exists (.x ? (@ == 14)))'::jsonpath;
+select '$.g ? (+x >= +-(+a + 2))'::jsonpath;
 
 select '$a'::jsonpath;
 select '$a.b'::jsonpath;