7 files changed, 43 insertions, 0 deletions
diff --git a/src/include/executor/execExpr.h b/src/include/executor/execExpr.h
index c830fcf7262..a41722ae1e4 100644
--- a/src/include/executor/execExpr.h
+++ b/src/include/executor/execExpr.h
@@ -240,6 +240,7 @@ typedef enum ExprEvalOp
 	EEOP_WINDOW_FUNC,
 	EEOP_SUBPLAN,
 	EEOP_JSON_CONSTRUCTOR,
+	EEOP_IS_JSON,
 
 	/* aggregation related nodes */
 	EEOP_AGG_STRICT_DESERIALIZE,
@@ -680,6 +681,12 @@ typedef struct ExprEvalStep
 			int			nargs;
 		}			json_constructor;
 
+		/* for EEOP_IS_JSON */
+		struct
+		{
+					JsonIsPredicate *pred;	/* original expression node */
+		}			is_json;
+
 	}			d;
 } ExprEvalStep;
 
@@ -774,6 +781,7 @@ extern void ExecEvalHashedScalarArrayOp(ExprState *state, ExprEvalStep *op,
 extern void ExecEvalConstraintNotNull(ExprState *state, ExprEvalStep *op);
 extern void ExecEvalConstraintCheck(ExprState *state, ExprEvalStep *op);
 extern void ExecEvalXmlExpr(ExprState *state, ExprEvalStep *op);
+extern void ExecEvalJsonIsPredicate(ExprState *state, ExprEvalStep *op);
 extern void ExecEvalGroupingFunc(ExprState *state, ExprEvalStep *op);
 extern void ExecEvalSubPlan(ExprState *state, ExprEvalStep *op,
 							ExprContext *econtext);
diff --git a/src/include/nodes/makefuncs.h b/src/include/nodes/makefuncs.h
index e50b933288d..380940968bd 100644
--- a/src/include/nodes/makefuncs.h
+++ b/src/include/nodes/makefuncs.h
@@ -110,6 +110,9 @@ extern JsonFormat *makeJsonFormat(JsonFormatType type, JsonEncoding encoding,
 								  int location);
 extern JsonValueExpr *makeJsonValueExpr(Expr *expr, JsonFormat *format);
 extern Node *makeJsonKeyValue(Node *key, Node *value);
+extern Node *makeJsonIsPredicate(Node *expr, JsonFormat *format,
+								 JsonValueType vtype, bool unique_keys,
+								 int location);
 extern JsonEncoding makeJsonEncoding(char *name);
 
 #endif							/* MAKEFUNC_H */
diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h
index ca440eb75ff..e8f30367a48 100644
--- a/src/include/nodes/nodes.h
+++ b/src/include/nodes/nodes.h
@@ -505,6 +505,7 @@ typedef enum NodeTag
 	T_JsonAggConstructor,
 	T_JsonObjectAgg,
 	T_JsonArrayAgg,
+	T_JsonIsPredicate,
 	T_JsonKeyValue,
 	T_JsonOutput,
 
diff --git a/src/include/nodes/primnodes.h b/src/include/nodes/primnodes.h
index c48527e998a..f4a39653ac6 100644
--- a/src/include/nodes/primnodes.h
+++ b/src/include/nodes/primnodes.h
@@ -1317,6 +1317,32 @@ typedef struct JsonConstructorExpr
 	int			location;
 } JsonConstructorExpr;
 
+/*
+ * JsonValueType -
+ *		representation of JSON item type in IS JSON predicate
+ */
+typedef enum JsonValueType
+{
+	JS_TYPE_ANY,				/* IS JSON [VALUE] */
+	JS_TYPE_OBJECT,				/* IS JSON OBJECT */
+	JS_TYPE_ARRAY,				/* IS JSON ARRAY*/
+	JS_TYPE_SCALAR				/* IS JSON SCALAR */
+} JsonValueType;
+
+/*
+ * JsonIsPredicate -
+ *		untransformed representation of IS JSON predicate
+ */
+typedef struct JsonIsPredicate
+{
+	NodeTag		type;
+	Node	   *expr;			/* untransformed expression */
+	JsonFormat *format;			/* FORMAT clause, if specified */
+	JsonValueType value_type;	/* JSON item type */
+	bool		unique_keys;	/* check key uniqueness? */
+	int			location;		/* token location, or -1 if unknown */
+} JsonIsPredicate;
+
 /* ----------------
  * NullTest
  *
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index 10829941e0d..c0ffa516d06 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -374,6 +374,7 @@ PG_KEYWORD("row", ROW, COL_NAME_KEYWORD, BARE_LABEL)
 PG_KEYWORD("rows", ROWS, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("rule", RULE, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("savepoint", SAVEPOINT, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("scalar", SCALAR, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("schema", SCHEMA, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("schemas", SCHEMAS, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("scroll", SCROLL, UNRESERVED_KEYWORD, BARE_LABEL)
diff --git a/src/include/utils/json.h b/src/include/utils/json.h
index 63d83b815fb..bfe5b215912 100644
--- a/src/include/utils/json.h
+++ b/src/include/utils/json.h
@@ -26,5 +26,6 @@ extern Datum json_build_object_worker(int nargs, Datum *args, bool *nulls,
 									  bool unique_keys);
 extern Datum json_build_array_worker(int nargs, Datum *args, bool *nulls,
 									 Oid *types, bool absent_on_null);
+extern bool json_validate(text *json, bool check_unique_keys);
 
 #endif							/* JSON_H */
diff --git a/src/include/utils/jsonfuncs.h b/src/include/utils/jsonfuncs.h
index 865b2ff7c11..cd16b6c0c84 100644
--- a/src/include/utils/jsonfuncs.h
+++ b/src/include/utils/jsonfuncs.h
@@ -45,6 +45,9 @@ extern void pg_parse_json_or_ereport(JsonLexContext *lex, JsonSemAction *sem);
 /* report an error during json lexing or parsing */
 extern void json_ereport_error(JsonParseErrorType error, JsonLexContext *lex);
 
+/* get first JSON token */
+extern JsonTokenType json_get_first_token(text *json, bool throw_error);
+
 extern uint32 parse_jsonb_index_flags(Jsonb *jb);
 extern void iterate_jsonb_values(Jsonb *jb, uint32 flags, void *state,
 								 JsonIterateStringValuesAction action);