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SET AS [DIRECT] action

Function


The action allows to change object's link to
  • local variable of ALIAS type,
  • item of an structure of Object type (reference to an object):

Declaration


SET dstIdent  AS srcIdent [DIRECT]


Parameters


dstIdent in Destination of values and links (value identifier of ALIAS type (or Object type in case of a structure item) row identifier, or whole structure identifier).
srctIdent

in

 Source of values and links (value identifier of ALIAS type (or Object type in case of a structure item) row identifier, or whole structure identifier).

Description

The structure type and the size of dstIdent and srcIdent must be identical (otherwise the action generates the error _ERR_RECORD_NO_COMP). Their type may be:

  • RECORD,
  • ALIAS,
  • Object of Structured variable type

The action sets the values of items from srcIdent_Rec to the values of items in dstIdent_Rec. If the parameter dstIdent_Rec is the reference to a row, then the parameter srcIdent_Rec must be the reference to a row, too. Accordingly, if dstIdent_Rec is the reference to a whole value, srcIdent_Rec must be the reference to a whole value, too.

The action rules are similar to the action SET WITH rules.

  • The same function for items of structures of a type other than Object (reference to an object).
  • For an item of Object type, it doesn't assign a value, but changes linked object.

Action allows using row index 0 in following case:

SET dstIdent[0]^Col1 AS srcIdent[0]^Col2 whereby

1. dstIdent is local structured variable and Col1 is of Object type
2. srcIdent is:
  • local structured variable and  Col2 is of Objekt type
  • type ALIAS (ALIAS (structDef) _rA) and Col2 is of Object type
  • object type structured variable; it is possible to use key word DIRECT
    (if Col2 is not type reference to object, DIRECT is obligatory)

Action realizes specified command (SET AS) for all rows of the column.
Hence the sizes of both structures (dstIdent and srcIdent) must be identical.


Example
 ALIAS _a
 INT   _i
 
 SET _a AS U.INT
 
 ; the first test
 IF U.Int = _a THEN
 ENDIF
 
 ; the second test
 _i := U.Int
 IF U.Int = _i THEN
 ENDIF

 

The first test for the value equality will be always true, because the local variable _a of ALIAS type is ''pointed'' to the object U.Int. 

The result of the second test depends on it, whether the object U.Int has not changed its value since the moment when the value was assigned to _i and the test executed.

Value change:


 
 ALIAS _a
 
 SET _a AS U.INT
 _a := 1

 

Assignment is interpreted by the script as the assigning the value of 1 to U.Int !!!.

Facilities of a local variable of ALIAS type are identical with items of Object type

  • objects of Structured variable type,
  • local variables of RECORD type (without the modifier NOALIAS).

For example:


 
 ALIAS _a
 
 SET _a AS U.Int
 _a := 1  ; the first assignment
 
 RECORD (SD.RecordDef) _lArr1
 SET _lArr1[1]^Object AS U.Int
 _lArr1[1]^Object := 1  ; the second assignment

 

The first and also the second assignment has the same effect, in regard of the object U.Int.

Change of pointing an Object type item of a Structured variable type object:


 
 SET  SV.Structure[1]^Object AS U.Int

 

The action will point the item SV.Structurea[1]^Object to the object U.Int. From this moment, the value of the item will be identical with the value of the object U.Int. The assignment:


 
 SV.Structure[1]^Object := 1

 

It assigns the value of 1 to the object U.Int (analogous to the previous examples).


 
 RECORD (SD.RecordDef) _lArr1
 
 REDIM _lArr1[2]
 SET _lArr1[1]^Object AS U.Int             ; assignment 1
 SET _lArr1[2]^Object AS U.Int2            ; assignment 2
 SET _lArr1[1]^Object AS _lArr1[2]^Object  ; assignment 3

 

The meaning of the assignments of 1 and 2 is listed above. The meaning of the assignment 3 in the given context identical with the action SET _lArr1[1]^Object AS U.Int2. Or:


 
 SET SV.Structure[1]^Object AS U.Int             ; assignment 1
 WAIT
 SET SV.Structure[2]^Object AS U.Int2            ; assignment 2
 WAIT
 SET SV.Structure[1]^Object AS SV.Structure[2]^Object  ; assignment 3
 WAIT

 

Analogous to the previous example, the last assignment is identical with the assignment SET SV.Structure[1]^Object AS U.Int2. As you can see from the example, it is copying the reference(s) declared on the right side (the identifier srcIdent).

Such a definition do not allow to point (make a reference) a structure item to another structure item. Therefore, there has been introduced the modifier DIRECT that makes it possible. The action SET AS DIRECT reduces possible types of parameters to these types:

dstIdent - Object type item of a RECORD type local variable, of a local variable ''typed alias'', or of a Structured variable type object.
srcIdent - item of a Structured variable type object.

For example:


 
 RECORD (SD.RecordDef) _lArr1
 
 REDIM _lArr1[2]
 SET _lArr1[1]^Object AS U.Int DIRECT               ;assignment 1
 SET  _lArr1[2]^Object AS U.Int2 DIRECT              ;assignment 2
 SET _lArr1[1]^Object AS _lArr1[2]^Object DIRECT    ;assignment 3
 SET  _lArr1[1]^Object AS SV.Structure[2]^Int DIRECT ;assignment 4

 


The assignments 1, 2, 3 are not admissible. The assignment 4 points to the item of the Structured variable type object.

If HOBJ of structured variable only is known, the setting of the reference on its field can be done as follows:

SET _locRec[2]^Object AS (HOBJ, ROW, COL) DIRECT

For example:


 
 ; used objects
  ; SD.Active: Structure definition with one column of Object type. Column name is "Object".
  ; SV.Active: two line structured variable of SD.Active type
 RECORD (SD.Active) _b
 BOOL _bOpenOk
 

 ; creating of the reference from the field SV.Active[1]^Object to the field in row 1, column 1 of object with a unique identifier 2131 (HOBJ)
 ; if object 2131 is not structured variable or row index/column index is outside the range, the action will not be done
 SET SV.Active[1]^Object AS (2131, 10, 10) DIRECT
  ; unsuccessful process of previous action will generate Run-Time error
 WAIT
 

  ; creating of the reference from the field _b[1]^Object to the field in row 2, column 1 of the object with unique identifier 24623 (HOBJ)
  ; unlike the previous example, the object 24623 must be opened
 _bOpenOk := %OpenRefToObject(24623, @TRUE)
 IF _bOpenOk THEN
 SET _b[1]^Object AS (24623, 2, 1) DIRECT
 ENDIF

 

!!! The action SET SV.Structure[1]^Object AS U.Int (analogous to the assignment of value to object) is processed by means of the process D2000 Server. It takes an effect later, in dependence on the system load. In the script, using WAIT action allows to wait for its execution!!!

The action allows to change the value of ALIAS type.



ALIAS (SD._System_Redundancy) _aT 
 ALIAS (SD._System_Redundancy) _aT1 
 SET _aT AS SV._System_Redundancy 
 SET _aT1 AS _aT

 
The revision of admissibility of assignment in regard of structure will be made when the ESL script is saved.
The value of ALIAS type can be changed without revision in following way:
 
BOOL _bOk  
 ALIAS (SD._System_Redundancy) _aT
 INT _hbj

 ; example 1
 _hbj := SV._System_Redundancy\HBJ 
 SET _aT AS (_hbj)

 ; example 2
 _hbj := %StrToHBJ("SV._System_Redundancy") 
 _bOk := %OpenRefToObject(_hbj, @TRUE) 
 SET _aT AS (_hbj)

 ; or example 3
 ALIAS _a 
 _hbj := %StrToHBJ("SV._System_Redundancy")
 _bOk := %OpenRefToObject(_hbj, @TRUE)
 SET _a AS (_hbj)
 SET _aT AS _a

 
The revision of assignment will be made when the action is executed and ESL script (or object containing the ESL script) must contain the reference to assigned structured variable or this reference was created by the script calling of the function %OpenRefToObject.
 
See also:

Related pages:

Script actions

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