TAL Programmer's Guide

Emulating Pascal Variant Parts

Using Equivalenced Variables

096254 Tandem Computers Incorporated 10–21

Emulating Pascal

Variant Parts

You can simulate variant parts of a Pascal record type by using equivalenced

structures as follows. (For information on record type variant parts, see the Pascal

Reference Manual.)

LITERAL triangle, rectangle, circle;

STRUCT geometry (*);

BEGIN

REAL x, y;

REAL area;

INT shape; ! 0 = TRIANGLE,

! 1 = RECTANGLE,

! 2 = CIRCLE

STRUCT triangle_info; !If SHAPE = TRIANGLE

BEGIN

REAL side1, side2, side3;

REAL(64) angle1, angle2, angle3;

END;

STRUCT rectangle_info = triangle_info;

!If SHAPE = RECTANGLE

BEGIN

REAL side1, side2;

END;

STRUCT circle_info = triangle_info;

!If SHAPE = CIRCLE

BEGIN

REAL diameter;

END;