WARNING in pile mode

[Ralf Hemmecke]

Look at the following functions.
You might get trapped.

PP ==> PostiveInteger
C ==> Fraction Integer
expTruncated1(s: PP, t: C): C ==
z: C := 1 + t -- truncated exp
n: PP := 1 -- exponent for t
p: C := t -- power of t, p=t^n
f: C := 1 -- factorial, f=n!
while n < s repeat
n := n + 1;
p := p * t;
f := n * f;
z := z + p / f;
z

expTruncated2(s: PP, t: C): C ==
z: C := 1 + t -- truncated exp
n: PP := 1 -- exponent for t
p: C := t -- power of t, p=t^n
f: C := 1 -- factorial, f=n!
while n < s repeat
n := n + 1; p := p * t; f := n * f; z := z + p / f;
z

The expTruncated1 function behaves as expected.
The second function is not the same if the line following the "while"
keyword is enclosed in parentheses.

while n < s repeat
(n := n + 1; p := p * t; f := n * f; z := z + p / f);

Actually that is pretty clear since

while n < s repeat
n := n + 1; p := p * t; f := n * f; z := z + p / f;

and

while n < s repeat n := n + 1; p := p * t; f := n * f; z := z + p / f;

are the same according to the pile rules and then only the "n:=n+1"
belongs to the loop body and not the whole line.

So the code for expTruncated2 is OK, but somewhat hard to interpret for
the not-so-familiar eye.

Just a comment.

Ralf