sort_fieldset_array_index_characters

The sort_fieldset_array_index_characters function sorts the indices of a FIELDSET array based on the elements in the array.

 sort_fieldset_array_index_characters (input;output;field;number of elements to sort)

The function sort_fieldset_array_index is of type BOOL and has four parameters:

1. input; ARRAY of type FIELDSET. This array contains the elements that must be sorted.
2. output; ARRAY of type NUMBER. This array receives the sorted indices.
3. field; TEXT. This is the Field in the FIELDSET that is used as the key to sort the array. If this Field is not present in the FIELDSET, it is considered empty.
4. number of elements to sort; NUMBER. This is the number of elements in the array that must be sorted starting from the first element. This can either be a number or a NUMBER variable or expression.

The function sort_fieldset_array_index_characters returns TRUE if the array was sorted successfully, and FALSE in one of the following conditions:

• If the number of elements to be sorted parameter is negative or 0.
• If the function sort_fieldset_array_index fails, the output array is unmodified. The input array is not modified by the function. The output array receives the sorted indices from the input array. If the output array is larger than the number of sorted elements, those elements outside the sorted range are left unmodified.

An example is provided here.

DDATASTRUCTURE DS
  BEGIN
    ARRAY FIELDSET Array[0]
  END

DECLARE input DEFINED_AS DS

ARRAY NUMBER output[0]
NUMBER i

ASSIGN input.Array[1].Key := "c"
ASSIGN input.Array[2].Key := "d"
ASSIGN input.Array[3].Key := "a"
ASSIGN input.Array[4].Key := "b"

IF sort_fieldset_array_index_characters (input.Array; output; "Key"; 4) THEN
  FOR i FROM 1 UPTO 4
  DO
#
@(i) @(input.Array[ output[i] ].Key)
#
  OD
ELSE
#
Failed to sort the input.
#
  STOP
FI

The type BOOL of the sort_filedset_array_index_characters function is used to implement error handling. If the sort succeeds, the return value of the function is TRUE, the IF statement becomes TRUE, and the THEN part is executed. If the return is FALSE, the ELSE part of the IF statement is executed.

This example produces the same result as the example included with the function sort_fieldset_array_characters (see sort_fieldset_array_characters).