As previously stated, you can combine a preceding variable with a character string by placing a period between them (&PROGRAM.A). If the preceding variable is nested, place an additional period after the variable for each level of nesting. For example,

SET &BUDGET = June
SET &PROGRAM = &budget
call mylib(&PROGRAM.A)          /* result: call mylib(JuneA)

If the character string precedes the variable, no period is required:

SET &BUDGET = June
SET &PROGRAM = &budget
call mylib(A&PROGRAM)           /* result: call mylib(AJune)