User flags.

You may change the behavior of Erable by clearing or setting some user flags (and the system flag -27). Here are the most important flags of Erable (see section (D) for a complete list):

• flag 1: display flag (if set then verbose mode selected)
• flag 10: integer arithmetic (if set then Erable expects integer arguments for instructions like GCD3, ABCUV or DIV2).
• flag 12: simplification flag (if set then Erable calls the gcd algorithm if needed)
• flag 13: complex flag (if cleared, all expressions are assumed to be real and Erable tries to return only real expressions)
• flag 15: real are integer flag (if set, real are assumed to be integer)
• flag 21: recurse flag (if set, the simplification algorithms EXPA and TSIMP will simplify in subexpressions)
• system flag -27: if set, then the user representation of complex numbers is symbolic.

To set a flag (e.g. flag 13), type 13 SF. To clear this flag, type 13 CF.