The break command exits a loop without finishing it.
Define a program:
| testbreak(a,b):={ local r; while (true) { if (b==0) { break; } r:=irem(a,b); a:=b; b:=r; } return a; } |
Then:
| testbreak(4,0) |
|
since the while loop is interrupted when b is 0 and a is 4.