Function: for
Section: programming/control
C-Name: forpari
Prototype: vV=GGI
Help: for(X=a,b,seq): the sequence is evaluated, X going from a up to b.
 If b is set to +oo, the loop will not stop.
Doc: evaluates \var{seq}, where
 the formal variable $X$ goes from $a$ to $b$. Nothing is done if $a>b$.
 $a$ and $b$ must be in $\R$. If $b$ is set to \kbd{+oo}, the loop will not
 stop; it is expected that the caller will break out of the loop itself at some
 point, using \kbd{break} or \kbd{return}.
