That's awesome. Thanks.
Motivated by this, I went a step further by defining
the following generalization:
oper := proc(x :: evaln, operator, d)
assign(x, `operator`(eval(x),d));
Now:
oper(x, `+`, 1); # increments x by 1,
oper(x, `-`, 4); # decrements x by 4,
oper(x, `*`, 3); # triples x
oper(x, `/`, 2); # halves x
Thanks again.
--
Rouben Rostamian