When displaying long lists and other large values, utop wraps them at about 80 columns, even when my terminal window is wider. How can I change the output width?
The only thing that I have found that might have provided the solution is UTop.size, which has type LTerm_geom.size React.signal, and seems to correctly record the size of my terminal window. In this example my terminal window had dimensions 164x37:
# #require "react";;
# #require "lambda-term";;
# React.S.value UTop.size;;
- : LTerm_geom.size = {LTerm_geom.rows = 37; cols = 164}
However, the value of cols doesn't seem to affect how values are displayed. For example, this is copied from the same session (with line breaks as they were displayed):
# List.hd algs;;
- : (int list * float) list =
[([2; 1; 0], 1.); ([2; 1], 0.54148398267); ([2; 0], 0.677137905076);
([2], 0.218621887745); ([1; 0], 0.781378112255); ([1], 0.322862094924);
([0], 0.45851601733); ([], 0.)]
There is a function called UTop.set_margin_function:
μ> #typeof "UTop.set_margin_function";;
val UTop.set_margin_function : (LTerm_geom.size -> int option) -> unit
Here is a simplistic example usage:
μ> UTop.set_margin_function (fun _ -> Some 150);;
After this point utop will use about 150 columns for printing out the results.
Here is an example session (shell + utop):
> utop -version
The universal toplevel for OCaml, version 1.19.3, compiled for OCaml version 4.04.1
> cat ~/.ocamlinit
(* Added by OPAM. *)
let () =
try Topdirs.dir_directory (Sys.getenv "OCAML_TOPLEVEL_PATH")
with Not_found -> ()
;;
> cat ~/.utoprc
cat: .utoprc: No such file or directory
> utop
utop # gen_nat_list 1 50;; (* gen_nat_list is some test function *)
- : int list =
[1; 2; 3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17; 18; 19; 20; 21; 22;
23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41;
42; 43; 44; 45; 46; 47; 48; 49; 50]
utop # UTop.set_margin_function (fun _ -> Some 150);;
utop # gen_nat_ist 1 50;;
- : int list =
[1; 2; 3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17; 18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39;
40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 50]