Can I build a graphical interface from ocaml toplevel?

Question

À few questions regarding the interactive toplevel and graphical UI programming:

1. Is it possible to build a graphical interface dynamically from ocaml toplevel?

2. It is possible to use the Graphics library too?

Answer 1

1. You can use the LWT toplevel with integration with the lablgtk main loop:

install lwt-glib and lablgtk, on debian based systems:

apt-get install liblwt-glib-ocaml-dev liblablgtk2-ocaml-dev

in the OCaml toplevel, load everything:

#use "topfind";;
#require "lwt.simple-top";;
#require "lwt.glib";;
#require "lablgtk2";;

then initialise the GTK and the LWT integration:

GMain.init ();;
Lwt_glib.install ();;

And play:

let w = GWindow.window ();;
w#show ();;

2. Graphics does not have a main loop like GTK, so there is no problem there. But inside a GTK application you should use cairo instead.