expression
The integer or string expression to be evaluated.
If you specify an integer expression, the F$STRING function evaluates 
the expression, converts the resulting integer to a string, and returns 
the result. If you specify a string expression, the F$STRING function 
evaluates the expression and returns the result.
When converting an integer to a string, the F$STRING function uses 
decimal representation and omits leading zeros. When converting a 
negative integer, the F$STRING function places a minus sign at the 
beginning string representation of the integer.
The F$STRING function in this example converts the result of the 
integer expression (--2 + A) to the numeric string, "3". 
First, the F$STRING function evaluates the expression (--2 + A). Note 
that 5, the value of symbol A, is automatically substituted when the 
integer expression is evaluated.
After the integer expression is evaluated, the F$STRING function 
converts the resulting integer, 3, to the string "3". This 
string is assigned to the symbol B.