Implement various jsonpath methods

This commit implements ithe jsonpath .bigint(), .boolean(),
.date(), .decimal([precision [, scale]]), .integer(), .number(),
.string(), .time(), .time_tz(), .timestamp(), and .timestamp_tz()
methods.

.bigint() converts the given JSON string or a numeric value to
the bigint type representation.

.boolean() converts the given JSON string, numeric, or boolean
value to the boolean type representation.  In the numeric case, only
integers are allowed. We use the parse_bool() backend function
to convert a string to a bool.

.decimal([precision [, scale]]) converts the given JSON string
or a numeric value to the numeric type representation.  If precision
and scale are provided for .decimal(), then it is converted to the
equivalent numeric typmod and applied to the numeric number.

.integer() and .number() convert the given JSON string or a
numeric value to the int4 and numeric type representation.

.string() uses the datatype's output function to convert numeric
and various date/time types to the string representation.

The JSON string representing a valid date/time is converted to the
specific date or time type representation using jsonpath .date(),
.time(), .time_tz(), .timestamp(), .timestamp_tz() methods.  The
changes use the infrastructure of the .datetime() method and perform
the datatype conversion as appropriate.  Unlike the .datetime()
method, none of these methods accept a format template and use ISO
DateTime format instead.  However, except for .date(), the
date/time related methods take an optional precision to adjust the
fractional seconds.

Jeevan Chalke, reviewed by Peter Eisentraut and Andrew Dunstan.

1 files changed, 74 insertions, 4 deletions

diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 5e4eb52641d..8733a0eac66 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -82,15 +82,18 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %token	<str>		ANY_P STRICT_P LAX_P LAST_P STARTS_P WITH_P LIKE_REGEX_P FLAG_P
 %token	<str>		ABS_P SIZE_P TYPE_P FLOOR_P DOUBLE_P CEILING_P KEYVALUE_P
 %token	<str>		DATETIME_P
+%token	<str>		BIGINT_P BOOLEAN_P DATE_P DECIMAL_P INTEGER_P NUMBER_P
+%token	<str>		STRINGFUNC_P TIME_P TIME_TZ_P TIMESTAMP_P TIMESTAMP_TZ_P
 
 %type	<result>	result
 
 %type	<value>		scalar_value path_primary expr array_accessor
 					any_path accessor_op key predicate delimited_predicate
 					index_elem starts_with_initial expr_or_predicate
-					datetime_template opt_datetime_template
+					datetime_template opt_datetime_template csv_elem
+					datetime_precision opt_datetime_precision
 
-%type	<elems>		accessor_expr
+%type	<elems>		accessor_expr csv_list opt_csv_list
 
 %type	<indexs>	index_list
 
@@ -248,9 +251,59 @@ accessor_op:
 	| array_accessor				{ $$ = $1; }
 	| '.' any_path					{ $$ = $2; }
 	| '.' method '(' ')'			{ $$ = makeItemType($2); }
-	| '.' DATETIME_P '(' opt_datetime_template ')'
-									{ $$ = makeItemUnary(jpiDatetime, $4); }
 	| '?' '(' predicate ')'			{ $$ = makeItemUnary(jpiFilter, $3); }
+	| '.' DECIMAL_P '(' opt_csv_list ')'
+		{
+			if (list_length($4) == 0)
+				$$ = makeItemBinary(jpiDecimal, NULL, NULL);
+			else if (list_length($4) == 1)
+				$$ = makeItemBinary(jpiDecimal, linitial($4), NULL);
+			else if (list_length($4) == 2)
+				$$ = makeItemBinary(jpiDecimal, linitial($4), lsecond($4));
+			else
+				ereturn(escontext, false,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("invalid input syntax for type %s", "jsonpath"),
+						 errdetail(".decimal() can only have an optional precision[,scale].")));
+		}
+	| '.' DATETIME_P '(' opt_datetime_template ')'
+		{ $$ = makeItemUnary(jpiDatetime, $4); }
+	| '.' TIME_P '(' opt_datetime_precision ')'
+		{ $$ = makeItemUnary(jpiTime, $4); }
+	| '.' TIME_TZ_P '(' opt_datetime_precision ')'
+		{ $$ = makeItemUnary(jpiTimeTz, $4); }
+	| '.' TIMESTAMP_P '(' opt_datetime_precision ')'
+		{ $$ = makeItemUnary(jpiTimestamp, $4); }
+	| '.' TIMESTAMP_TZ_P '(' opt_datetime_precision ')'
+		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
+	;
+
+csv_elem:
+	INT_P
+		{ $$ = makeItemNumeric(&$1); }
+	| '+' INT_P %prec UMINUS
+		{ $$ = makeItemUnary(jpiPlus, makeItemNumeric(&$2)); }
+	| '-' INT_P %prec UMINUS
+		{ $$ = makeItemUnary(jpiMinus, makeItemNumeric(&$2)); }
+	;
+
+csv_list:
+	csv_elem						{ $$ = list_make1($1); }
+	| csv_list ',' csv_elem			{ $$ = lappend($1, $3); }
+	;
+
+opt_csv_list:
+	csv_list						{ $$ = $1; }
+	| /* EMPTY */					{ $$ = NULL; }
+	;
+
+datetime_precision:
+	INT_P							{ $$ = makeItemNumeric(&$1); }
+	;
+
+opt_datetime_precision:
+	datetime_precision				{ $$ = $1; }
+	| /* EMPTY */					{ $$ = NULL; }
 	;
 
 datetime_template:
@@ -291,6 +344,17 @@ key_name:
 	| WITH_P
 	| LIKE_REGEX_P
 	| FLAG_P
+	| BIGINT_P
+	| BOOLEAN_P
+	| DATE_P
+	| DECIMAL_P
+	| INTEGER_P
+	| NUMBER_P
+	| STRINGFUNC_P
+	| TIME_P
+	| TIME_TZ_P
+	| TIMESTAMP_P
+	| TIMESTAMP_TZ_P
 	;
 
 method:
@@ -301,6 +365,12 @@ method:
 	| DOUBLE_P						{ $$ = jpiDouble; }
 	| CEILING_P						{ $$ = jpiCeiling; }
 	| KEYVALUE_P					{ $$ = jpiKeyValue; }
+	| BIGINT_P						{ $$ = jpiBigint; }
+	| BOOLEAN_P						{ $$ = jpiBoolean; }
+	| DATE_P						{ $$ = jpiDate; }
+	| INTEGER_P						{ $$ = jpiInteger; }
+	| NUMBER_P						{ $$ = jpiNumber; }
+	| STRINGFUNC_P					{ $$ = jpiStringFunc; }
 	;
 %%