1. ASSIGN Statement

The assignment statement evaluates an expression and assigns a result value to one or more target variables. If a target or pseudo variable attributes are different from source attributes, data conversion will be required.

figure syntax assignment
ASSIGN Statement
Component Description

reference

A target or pseudo variable.

expression

A source expression.

BY NAME

An option used in a structure assignment. For more information, refer to "Assignment Execution".

Compound Assignment Statement

A compound assignment statement uses compound assignment operations.

figure syntax assignment compound
Compound Assignment Statement
Component Description

reference

Target variable or pseudo variable.

compound operator

Operator to apply to the source and target before the assignment is made.

Compound operators that can be used in an assignment statement are:

  • +=: Add and then assign

  • -=: Subtract and then assign

  • *=: Multiply and then assign

  • /=: Divide and then assign

  • **=: Exponentiate and then assign

  • ||=: Concatenate and then assign

  • |=: or and then assign

  • &=: and and then assign

  • ^= or <>: exclusive-or and then assign

expression

Expression of the source.

The following are examples of executing compound assignment statements.

 X += 5;      ==> X = X + 5;
 X *= Y - 1;  ==> X = X * (Y - 1);

Target Variables

Target variables can be elements, arrays, structures, or pseudo variables.

  • Array

    • A target variable must be an array of scalars or structures. A source must be a scalar expression or an expression with the same number of dimensions and the same bounds as a target.

  • Structure

    • If BY NAME is specified, each target and source must be a structure.

    • If BY NAME is not specified, each target must be a structure and each source must be a scalar or a structure that is the same as a target.

    • If BY NAME is not specified and a source is described as a NULL string("") then:

      1. all targets will be padded with '00’X.

      2. all numeric targets will 0.

      3. all character and graphic targets will be padded with blanks.

Assignment Execution

  • Array

    • All array operands (of sources and targets) must have the same number of dimensions and the same bounds.

    • An array assignment is expanded into a loop as follows:

       DO I1 = LBOUND( target-variable, 1 ) to HBOUND( target-variable, 1 );
 DO I2 = LBOUND( target-variable, 2 ) to HBOUND( target-variable, 2 );
...
 DO IN = LBOUND( target-variable, N ) to HBOUND( target-variable, N );

   generated element assignment ;

 END;

    • N is the number of dimensions of a target. In the generated element assignment, I1 through IN are used as subscripts. If a source is scalar, subscripts will not be used.

  • Structure

    • If BY NAME is not specified:

      • All operands must be the same structure, not an array. The member of a structure can be an array.

      • An assignment will be executed on each member. If the number of members is n, assignments will be executed n times.

      • If a member is an aggregate, assignments will be executed on all members of the member.

    • If BY NAME is specified:

      1. The same name as the name of a target structure member will be searched from a source from the first member. The members will be direct children of the structure, not children of a child of the structure.

      2. A search will be repeated until a same name is found.

      3. If a searched member is a structure or an array of structures, an assignment with the BY NAME option will be executed.

      4. If a searched member is a scalar or an array of scalars, an element assignment will be executed.

      5. The above steps will be repeated for following members.

    • The following is an example of a structure assignment using BY NAME:

       DCL 1 ONE,              DCL 1 TWO,              DCL 1 THREE
       2 PART1,                2 PART1,                2 PART1,
         3 RED,                  3 BLUE,                 3 RED,
         3 ORANGE,               3 GREEN,                3 BLUE,
       2 PART2,                  3 RED,                  3 BROWN,
         3 YELLOW,             2 PART2,                2 PART2,
         3 BLUE,                 3 BROWN,                3 YELLOW,
         3 GREEN;                3 YELLOW;               3 GREEN;