Can a program take in an expression unevaluated?

[CH3791]

Hi guys,

Is there a way to get a CAS program, after it accepts an expression, to not evaluate it?

For example, say this is the program:

Code:

#cas
prg1(expression1):=
BEGIN
  return subst(expression1,'X=x');
END;
#end

Let's say that expression1 is equal to X^2. By the time expression1 is used in my code, the calc would already have evaluated X^2 using whatever value X has.

So I was wondering if there was something like this:

Code:

#cas
prg1(QUOTE(expression1)):=
BEGIN
  return subst(expression1,'X=x');
END;
#end

to tell the calculator not to evaluate the argument. Cos I honestly can't be bothered typing single quotes each time.