Function: mapput
Section: programming/specific
C-Name: mapput
Prototype: vWGG
Help: mapput(M,x,y): associates x to y in the map M.
Doc: Associates $x$ to $y$ in the map $M$. The value $y$ can be retrieved
 with \tet{mapget}.
 \bprog
 ? M = Map();
 ? mapput(M, "foo", 23);
 ? mapput(M, 7718, "bill");
 ? mapget(M, "foo")
 %4 = 23
 ? mapget(M, 7718)
 %5 = "bill"
 ? Vec(M)  \\ keys
 %6 = [7718, "foo"]
 ? Mat(M)
 %7 =
 [ 7718 "bill"]

 ["foo"     23]
 @eprog
