%mathpiper,def="--"

Function("--",{aVar})
[
   MacroBind(aVar,SubtractN(Eval(aVar),1));

   Eval(aVar);
];

UnFence("--",1);

HoldArgument("--",aVar);

%/mathpiper




%mathpiper_docs,name="--",categories="Operators"
*CMD -- --- decrement variable
*STD
*CALL
	var--

*PARMS

{var} -- variable to decrement

*DESC

The variable with name "var" is decremented, i.e. the number 1 is
subtracted from it. The expression {x--} is
equivalent to the assignment {x := x - 1}.

*E.G.
In> x := 5;
Result: 5;

In> x--;
Result: 4;

In> x;
Result: 4;

*SEE ++, :=
%/mathpiper_docs