Short syntax for UNLIST with IN operator (#8878)

* Feature implementation

* Addition to documentation

* Documentation adjustments

* The code is consistent with the description.

* Type inference based on comparison parameter

* Removing development artifacts

* Redundant variable has been removed

---------

Co-authored-by: alexey.chudaykin <alexey.chudaykin@red-soft.ru>

Author: ChudaykinAlex

doc/sql.extensions/README.unlist

@@ -74,5 +74,45 @@ Unacceptable behavior:
 	SELECT UNLIST FROM UNLIST('UNLIST,A,S,A') AS A;
 
 
+Short syntax for UNLIST with IN operator:
+	UNLIST can be used directly with the IN operator without requiring a full subquery.
+	Instead of writing IN (SELECT * FROM UNLIST(...) AS U), you can use the shorter syntax IN UNLIST(...).
+
+Syntax:
+	<in predicate> ::=
+		<value> [NOT] IN <table value function unlist short>
+
+	<table value function unlist short> ::=
+		UNLIST ( <input> [, <separator>] [, <data type conversion>] )
+
+Examples:
+
+A)
+	SELECT * FROM EMPLOYEE WHERE EMP_NO IN UNLIST('2,4,5,7,11');
+B)
+	SELECT * FROM EMPLOYEE WHERE JOB_COUNTRY IN UNLIST('France,Italy,England');
+C)
+	SELECT EMP_NO FROM EMPLOYEE	WHERE JOB_COUNTRY NOT IN UNLIST('USA');
+D)
+	SELECT * FROM EMPLOYEE WHERE DEPT_NO IN UNLIST('100:110:115:120', ':' RETURNING INT);
+E)
+	SET AUTOTERM;
+	RECREATE PROCEDURE GET_EMPLOYEES_BY_PHONE_EXT (PHONE VARCHAR(1000))
+	RETURNS (EMPLOYEE_NAME VARCHAR(100))
+	AS
+	BEGIN
+		FOR
+			SELECT FIRST_NAME FROM EMPLOYEE
+			WHERE PHONE_EXT IN UNLIST(:PHONE, ',' RETURNING INT)
+			INTO :EMPLOYEE_NAME
+		DO
+			SUSPEND;
+	END;
+
+	SELECT A.EMPLOYEE_NAME FROM GET_EMPLOYEES_BY_PHONE_EXT('2,3,7') AS A;
+
+Note:
+	The short syntax automatically provides the correlation name and column name,
+	so they cannot be specified explicitly when using this form.
 
 

src/dsql/parse.y

@@ -7801,6 +7801,38 @@ in_predicate
 				ComparativeBoolNode::DFLAG_ANSI_ANY, $4);
 			$$ = newNode<NotBoolNode>(node);
 		}
+	| value IN table_value_function_unlist_short(NOTRIAL($1))
+		{
+			$$ = newNode<ComparativeBoolNode>(blr_eql, $1,
+				ComparativeBoolNode::DFLAG_ANSI_ANY, $3);
+		}
+	| value NOT IN table_value_function_unlist_short(NOTRIAL($1))
+		{
+			const auto node = newNode<ComparativeBoolNode>(blr_eql, $1,
+				ComparativeBoolNode::DFLAG_ANSI_ANY, $4);
+			$$ = newNode<NotBoolNode>(node);
+		}
+	;
+
+%type <exprNode> table_value_function_unlist_short(<valueExprNode>)
+table_value_function_unlist_short($autoTypeFromValue)
+	: table_value_function_unlist
+		{
+			const auto unlistNode = nodeAs<UnlistFunctionSourceNode>($1);
+			unlistNode->alias = UnlistFunctionSourceNode::FUNC_NAME;
+
+			if (unlistNode->dsqlField == nullptr)
+				unlistNode->dsqlAutoTypeFromValue = $autoTypeFromValue;
+
+			const auto rseNode = newNode<RseNode>();
+			rseNode->dsqlFlags |= RecordSourceNode::DFLAG_BODY_WRAPPER;
+			rseNode->dsqlFrom = newNode<RecSourceListNode>(unlistNode);
+
+			const auto selectNode = newNode<SelectExprNode>();
+			selectNode->querySpec = rseNode;
+
+			$$ = selectNode;
+		}
 	;
 
 %type <boolExprNode> exists_predicate

src/jrd/RecordSourceNodes.cpp

@@ -4380,14 +4380,22 @@ dsql_fld* UnlistFunctionSourceNode::makeField(DsqlCompilerScratch* dsqlScratch)
 		field = newField;
 
 		dsc desc;
-		DsqlDescMaker::fromNode(dsqlScratch, &desc, inputItem);
-		auto ttype = desc.getCharSet();
+		if (dsqlAutoTypeFromValue)
+		{
+			dsqlAutoTypeFromValue = Node::doDsqlPass(dsqlScratch, dsqlAutoTypeFromValue, false);
+			DsqlDescMaker::fromNode(dsqlScratch, &desc, dsqlAutoTypeFromValue);
+		}
+		else
+		{
+			DsqlDescMaker::fromNode(dsqlScratch, &desc, inputItem);
+			auto ttype = desc.getCharSet();
 
-		if (ttype == CS_NONE && !desc.isText() && !desc.isBlob())
-			ttype = CS_ASCII;
+			if (ttype == CS_NONE && !desc.isText() && !desc.isBlob())
+				ttype = CS_ASCII;
 
-		const auto bytesPerChar = DSqlDataTypeUtil(dsqlScratch).maxBytesPerChar(ttype);
-		desc.makeText(bytesPerChar * DEFAULT_UNLIST_TEXT_LENGTH, ttype);
+			const auto bytesPerChar = DSqlDataTypeUtil(dsqlScratch).maxBytesPerChar(ttype);
+			desc.makeVarying(bytesPerChar * DEFAULT_UNLIST_TEXT_LENGTH, ttype);
+		}
 		MAKE_field(newField, &desc);
 		newField->fld_id = 0;
 	}

src/jrd/RecordSourceNodes.h

@@ -1070,6 +1070,9 @@ class UnlistFunctionSourceNode : public TableValueFunctionSourceNode
 	{
 		return FUNC_NAME;
 	}
+
+public:
+	NestConst<ValueExprNode> dsqlAutoTypeFromValue;
 };
 
 class GenSeriesFunctionSourceNode final : public TableValueFunctionSourceNode