Question

I wish to do simultaneous variable assignment in Pascal.

As far as I know, it’s not possible. Googling on the issue, I can see that many programming languages implement that, but I can’t find how to do it in Pascal.

For example, in Python I can do this:

(x, y) = (y, x)

In Pascal, I need an additional variable to hold the value of x before it’s removed, something like this:

bubble := x;
x := y;
y := bubble;

So, is there simultaneous assignment in Pascal, or should I rewrite the code to something like the bubble thing above?

I don’t just have to do swaps; sometimes I have to do things like this:

(x,y) = (x+1,y+x)

Would it be ok to do it like the following?

old_x := x;
old_y := y;
x := x + 1; // maybe x := old_x + 1;
y := old_y + old_x;

Answer 1

PASCAL does not contain a simultaneous variable assignment.

Nor does it contain a SWAP(X,Y) predefined procedure.

You have to do it yourself.

You might want to consider buying a copy of [Jensen & Wirth]. It is still the best reference manual available on the language. If you are using one of the Borland PASCAL systems, use the manual that came with it: Borland made some incompatible changes, that nevertheless made the language significantly easier to use.