Allow jsonpath parenthized expressions to be a base part of a path

Author: Nikita Glukhov

src/backend/utils/adt/jsonpath.c

@@ -741,6 +741,13 @@ jspGetNext(JsonPathItem *v, JsonPathItem *a)
 			v->type == jpiRoot ||
 			v->type == jpiVariable ||
 			v->type == jpiLast ||
+			v->type == jpiAdd ||
+			v->type == jpiSub ||
+			v->type == jpiMul ||
+			v->type == jpiDiv ||
+			v->type == jpiMod ||
+			v->type == jpiPlus ||
+			v->type == jpiMinus ||
 			v->type == jpiType ||
 			v->type == jpiSize ||
 			v->type == jpiAbs ||

src/backend/utils/adt/jsonpath_exec.c

@@ -691,6 +691,7 @@ executeBinaryArithmExpr(JsonPathExecContext *cxt, JsonPathItem *jsp,
 	Datum		ldatum;
 	Datum		rdatum;
 	Datum		res;
+	bool		hasNext;
 
 	jspGetLeftArg(jsp, &elem);
 
@@ -722,7 +723,9 @@ executeBinaryArithmExpr(JsonPathExecContext *cxt, JsonPathItem *jsp,
 	if (rval->type != jbvNumeric)
 		return jperMakeError(ERRCODE_SINGLETON_JSON_ITEM_REQUIRED);
 
-	if (!found)
+	hasNext = jspGetNext(jsp, &elem);
+
+	if (!found && !hasNext)
 		return jperOk;
 
 	ldatum = NumericGetDatum(lval->val.numeric);
@@ -753,6 +756,9 @@ executeBinaryArithmExpr(JsonPathExecContext *cxt, JsonPathItem *jsp,
 	lval->type = jbvNumeric;
 	lval->val.numeric = DatumGetNumeric(res);
 
+	if (hasNext)
+		return recursiveExecute(cxt, &elem, lval, found);
+
 	*found = lappend(*found, lval);
 
 	return jperOk;
@@ -766,6 +772,7 @@ executeUnaryArithmExpr(JsonPathExecContext *cxt, JsonPathItem *jsp,
 	JsonPathItem elem;
 	List	   *seq = NIL;
 	ListCell   *lc;
+	bool		hasNext;
 
 	jspGetArg(jsp, &elem);
 	jper = recursiveExecuteAndUnwrap(cxt, &elem, jb, &seq);
@@ -775,6 +782,8 @@ executeUnaryArithmExpr(JsonPathExecContext *cxt, JsonPathItem *jsp,
 
 	jper = jperNotFound;
 
+	hasNext = jspGetNext(jsp, &elem);
+
 	foreach(lc, seq)
 	{
 		JsonbValue *val = lfirst(lc);
@@ -785,12 +794,10 @@ executeUnaryArithmExpr(JsonPathExecContext *cxt, JsonPathItem *jsp,
 
 		if (val->type == jbvNumeric)
 		{
-			jper = jperOk;
-
-			if (!found)
-				return jper;
+			if (!found && !hasNext)
+				return jperOk;
 		}
-		else if (!found)
+		else if (!found && !hasNext)
 			continue; /* skip non-numerics processing */
 
 		if (val->type != jbvNumeric)
@@ -811,7 +818,26 @@ executeUnaryArithmExpr(JsonPathExecContext *cxt, JsonPathItem *jsp,
 				elog(ERROR, "unknown jsonpath arithmetic operation %d", jsp->type);
 		}
 
-		*found = lappend(*found, val);
+		if (hasNext)
+		{
+			JsonPathExecResult jper2 = recursiveExecute(cxt, &elem, val, found);
+
+			if (jperIsError(jper2))
+				return jper2;
+
+			if (jper2 == jperOk)
+			{
+				if (!found)
+					return jperOk;
+				jper = jperOk;
+			}
+		}
+		else
+		{
+			Assert(found);
+			*found = lappend(*found, val);
+			jper = jperOk;
+		}
 	}
 
 	return jper;

src/backend/utils/adt/jsonpath_gram.y

@@ -142,18 +142,23 @@ makeItemUnary(int type, JsonPathParseItem* a)
 }
 
 static JsonPathParseItem*
-makeItemList(List *list) {
-	JsonPathParseItem	*head, *end;
-	ListCell	*cell;
+makeItemList(List *list)
+{
+	JsonPathParseItem *head, *end;
+	ListCell   *cell = list_head(list);
 
-	head = end = (JsonPathParseItem*)linitial(list);
+	head = end = (JsonPathParseItem *) lfirst(cell);
 
-	foreach(cell, list)
-	{
-		JsonPathParseItem	*c = (JsonPathParseItem*)lfirst(cell);
+	if (!lnext(cell))
+		return head;
 
-		if (c == head)
-			continue;
+	/* append items to the end of already existing list */
+	while (end->next)
+		end = end->next;
+
+	for_each_cell(cell, lnext(cell))
+	{
+		JsonPathParseItem *c = (JsonPathParseItem *) lfirst(cell);
 
 		end->next = c;
 		end = c;
@@ -359,6 +364,7 @@ path_primary:
 accessor_expr:
 	path_primary					{ $$ = list_make1($1); }
 	| '.' key						{ $$ = list_make2(makeItemType(jpiCurrent), $2); }
+	| '(' expr ')' accessor_op		{ $$ = list_make2($2, $4); }
 	| accessor_expr accessor_op		{ $$ = lappend($1, $2); }
 	;
 

src/test/regress/expected/jsonb_jsonpath.out

@@ -832,6 +832,18 @@ select _jsonpath_query(jsonb 'null', 'aaa.type()');
  "string"
 (1 row)
 
+select _jsonpath_query(jsonb '{"a": 2}', '($.a - 5).abs() + 10');
+ _jsonpath_query 
+-----------------
+ 13
+(1 row)
+
+select _jsonpath_query(jsonb '{"a": 2.5}', '-($.a * $.a).floor() + 10');
+ _jsonpath_query 
+-----------------
+ 4
+(1 row)
+
 select _jsonpath_query(jsonb '[1,null,true,"11",[],[1],[1,2,3],{},{"a":1,"b":2}]', 'strict $[*].size()');
 ERROR:  SQL/JSON array not found
 select _jsonpath_query(jsonb '[1,null,true,"11",[],[1],[1,2,3],{},{"a":1,"b":2}]', 'lax $[*].size()');

src/test/regress/expected/jsonpath.out

@@ -442,6 +442,36 @@ ERROR:  bad jsonpath representation
 LINE 1: select '$ ? (@ like_regex "pattern" flag "a")'::jsonpath;
                ^
 DETAIL:  unrecognized flag of LIKE_REGEX predicate at or near """
+select '($).a.b'::jsonpath;
+ jsonpath  
+-----------
+ $."a"."b"
+(1 row)
+
+select '($.a.b).c.d'::jsonpath;
+     jsonpath      
+-------------------
+ $."a"."b"."c"."d"
+(1 row)
+
+select '($.a.b + -$.x.y).c.d'::jsonpath;
+             jsonpath             
+----------------------------------
+ ($."a"."b" + -$."x"."y")."c"."d"
+(1 row)
+
+select '(-+$.a.b).c.d'::jsonpath;
+        jsonpath         
+-------------------------
+ (-(+$."a"."b"))."c"."d"
+(1 row)
+
+select '1 + ($.a.b + 2).c.d'::jsonpath;
+           jsonpath            
+-------------------------------
+ (1 + ($."a"."b" + 2)."c"."d")
+(1 row)
+
 select '$ ? (a < 1)'::jsonpath;
   jsonpath   
 -------------

src/test/regress/sql/jsonb_jsonpath.sql

@@ -169,6 +169,9 @@ select _jsonpath_query(jsonb 'null', '123.type()');
 select _jsonpath_query(jsonb 'null', '"123".type()');
 select _jsonpath_query(jsonb 'null', 'aaa.type()');
 
+select _jsonpath_query(jsonb '{"a": 2}', '($.a - 5).abs() + 10');
+select _jsonpath_query(jsonb '{"a": 2.5}', '-($.a * $.a).floor() + 10');
+
 select _jsonpath_query(jsonb '[1,null,true,"11",[],[1],[1,2,3],{},{"a":1,"b":2}]', 'strict $[*].size()');
 select _jsonpath_query(jsonb '[1,null,true,"11",[],[1],[1,2,3],{},{"a":1,"b":2}]', 'lax $[*].size()');
 

src/test/regress/sql/jsonpath.sql

@@ -81,6 +81,12 @@ select '$ ? (@ like_regex "pattern" flag "isim")'::jsonpath;
 select '$ ? (@ like_regex "pattern" flag "xsms")'::jsonpath;
 select '$ ? (@ like_regex "pattern" flag "a")'::jsonpath;
 
+select '($).a.b'::jsonpath;
+select '($.a.b).c.d'::jsonpath;
+select '($.a.b + -$.x.y).c.d'::jsonpath;
+select '(-+$.a.b).c.d'::jsonpath;
+select '1 + ($.a.b + 2).c.d'::jsonpath;
+
 select '$ ? (a < 1)'::jsonpath;
 select '$ ? (a < -1)'::jsonpath;
 select '$ ? (a < +1)'::jsonpath;