%SUBST(string:start{:length})%SUBST returns a portion of argument string. It may also be used as the result of an assignment with the EVAL operation code.
The start parameter represents the starting position of the substring.
The length parameter represents the length of the substring. If it is not specified, the length is the length of the string parameter less the start value plus one.
The string must be character, graphic, or UCS-2data. Starting position and length may be any numeric value or numeric expression with zero decimal positions. The starting position must be greater than zero. The length may be greater than or equal to zero.
When the string parameter is varying length, the values of the other parameters are checked against the current length, not the maximum length.
When specified as a parameter for a definition specification keyword, the parameters must be literals or named constants representing literals. When specified on a free-form calculation specification, the parameters may be any expression.
For more information, see String Operations or Built-in Functions.