Function: _forvec_start
Class: gp2c_internal
Help: Initializes parameters for forvec_start.
Description:
 (gen, small, &gen, &func_GG):vec    forvec_start($1, $2, &$3, &$4)

Function: _call_GG
Class: gp2c_internal
Help: Call a function with proto GG on two GENs.
Description:
 (func_GG, gen, gen):gen         $(1)($2, $3)

Function: forvec
Section: programming/control
C-Name: forvec
Prototype: vV=GID0,L,
Help: forvec(X=v,seq,{flag=0}): v being a vector of two-component vectors of
 length n, the sequence is evaluated with X[i] going from v[i][1] to v[i][2]
 for i=n,..,1 if flag is zero or omitted. If flag = 1 (resp. flag = 2),
 restrict to increasing (resp. strictly increasing) sequences.
Doc: Let $v$ be an $n$-component
 vector (where $n$ is arbitrary) of two-component vectors $[a_i,b_i]$
 for $1\le i\le n$. This routine evaluates \var{seq}, where the formal
 variables $X[1],\dots, X[n]$ go from $a_1$ to $b_1$,\dots, from $a_n$ to
 $b_n$, i.e.~$X$ goes from $[a_1,\dots,a_n]$ to $[b_1,\dots,b_n]$ with respect
 to the lexicographic ordering. (The formal variable with the highest index
 moves the fastest.) If $\fl=1$, generate only nondecreasing vectors $X$, and
 if $\fl=2$, generate only strictly increasing vectors $X$.

 The type of $X$ is the same as the type of $v$: \typ{VEC} or \typ{COL}.
