Allows to print nested boxes, lists, arrays, tables in several formats,
including:

• text (assuming monospace font)

• HTML (using tyxml )

• LaTeX (not implemented yet)

Documentation

See https://c-cube.github.io/printbox/

Build

Ideally, use opam:

$ opam install printbox printbox-text

Manually:

$ make install

A few examples

importing the module

# #require "printbox";;
# #require "printbox-text";;

# module B = PrintBox;;
module B = PrintBox

simple box

# let box = B.(hlist [ text "hello"; text "world"; ]);;
val box : B.t = <abstr>

# PrintBox_text.output stdout box;;
hello│world
- : unit = ()

less simple boxes

# let box =
  B.(hlist
  [ text "I love\nto\npress\nenter";
    grid_text [| [|"a"; "bbb"|];
    [|"c"; "hello world"|] |]
  ])
  |> B.frame;;
val box : B.t = <abstr>

# PrintBox_text.output stdout box;;
┌──────┬─┬───────────┐
│I love│a│bbb        │
│to    ├─┼───────────┤
│press │c│hello world│
│enter │ │           │
└──────┴─┴───────────┘
- : unit = ()

printing a table

# let square n =
  (* function to make a square *)
  Array.init n
    (fun i -> Array.init n (fun j -> B.sprintf "(%d,%d)" i j))
  |> B.grid ;;
val square : int -> B.t = <fun>

# let sq = square 5;;
val sq : B.t = <abstr>
# PrintBox_text.output stdout sq;;
(0,0)│(0,1)│(0,2)│(0,3)│(0,4)
─────┼─────┼─────┼─────┼─────
(1,0)│(1,1)│(1,2)│(1,3)│(1,4)
─────┼─────┼─────┼─────┼─────
(2,0)│(2,1)│(2,2)│(2,3)│(2,4)
─────┼─────┼─────┼─────┼─────
(3,0)│(3,1)│(3,2)│(3,3)│(3,4)
─────┼─────┼─────┼─────┼─────
(4,0)│(4,1)│(4,2)│(4,3)│(4,4)
- : unit = ()

frame

Why not put a frame around this? That's easy.

# let sq2 = square 3 |> B.frame ;;
val sq2 : B.t = <abstr>

# PrintBox_text.output stdout sq2;;
┌─────┬─────┬─────┐
│(0,0)│(0,1)│(0,2)│
├─────┼─────┼─────┤
│(1,0)│(1,1)│(1,2)│
├─────┼─────┼─────┤
│(2,0)│(2,1)│(2,2)│
└─────┴─────┴─────┘
- : unit = ()

tree

We can also create trees and display them using indentation:

# let tree =
  B.tree (B.text "root")
    [ B.tree (B.text "a") [B.text "a1\na1"; B.text "a2\na2\na2"];
      B.tree (B.text "b") [B.text "b1\nb1"; B.text "b2"; B.text "b3"];
    ];;
val tree : B.t = <abstr>

# PrintBox_text.output stdout tree;;
root
├─a
│ ├─a1
│ │ a1
│ └─a2
│   a2
│   a2
└─b
  ├─b1
  │ b1
  ├─b2
  └─b3
- : unit = ()

Installing the pretty-printer in the toplevel

PrintBox_text contains a Format-compatible pretty-printer that
can be used as a default printer for boxes.

# #install_printer PrintBox_text.pp;;
# PrintBox.(frame @@ frame @@ init_grid ~line:3 ~col:2 (fun ~line:i ~col:j -> sprintf "%d.%d" i j));;
- : B.t =
┌─────────┐
│┌───┬───┐│
││0.0│0.1││
│├───┼───┤│
││1.0│1.1││
│├───┼───┤│
││2.0│2.1││
│└───┴───┘│
└─────────┘
# #remove_printer PrintBox_text.pp;;

Note that this pretty-printer plays nicely with Format boxes:

# let b = PrintBox.(frame @@ hlist [text "a\nb"; text "c"]);;
val b : B.t = <abstr>
# Format.printf "some text %a around@." PrintBox_text.pp b;;
some text ┌─┬─┐
          │a│c│
          │b│ │
          └─┴─┘ around
- : unit = ()

Also works with basic styling on text now:

# let b2 = PrintBox.(
    let style = Style.(fg_color Red) in
  frame @@ hlist [text_with_style style "a\nb"; text "c"]);;
val b2 : B.t = <abstr>
# Format.printf "some text %a around@." (PrintBox_text.pp_with ~style:true) b2;;
some text ┌─┬─┐
          │a│c│
          │b│ │
          └─┴─┘ around
- : unit = ()

# let b3 = PrintBox.(
    let style = Style.(fg_color Red) in
    frame @@ grid_l [
      [text_with_style style "a\nb";
       line_with_style Style.(set_bold true @@ bg_color Green) "OH!"];
      [text "c"; text "ballot"];
    ])
val b3 : PrintBox.t = <abstr>
utop [1]: print_endline @@ PrintBox_text.to_string b3;;

gives .

Handling unicode

Unicode (utf8) text is handled.

# let b =
  PrintBox.(frame @@
    hlist [
      vlist[text "oï ωεird nums:\nπ/2\nτ/4";
        tree (text "0")[text "1"; tree (text "ω") [text "ω²"]]];
      frame @@ vlist [text "sum=Σ_i a·xᵢ²\n—————\n1+1"; text "Ōₒ\nÀ"]]);;
val b : B.t = <abstr>

# print_endline @@ PrintBox_text.to_string b;;
┌──────────────┬───────────────┐
│oï ωεird nums:│┌─────────────┐│
│π/2           ││sum=Σ_i a·xᵢ²││
│τ/4           ││—————        ││
├──────────────┤│1+1          ││
│0             │├─────────────┤│
│├─1           ││Ōₒ           ││
│└─ω           ││À            ││
│  └─ω²        │└─────────────┘│
└──────────────┴───────────────┘
- : unit = ()

HTML output (with tyxml)

Assuming you have loaded printbox-html somehow:

let out = open_out "/tmp/foo.html";;
output_string out (PrintBox_html.to_string_doc (square 5));;

which prints some HTML in the file foo.html.
Note that trees are printed in HTML using nested lists, and
that PrintBox_html.to_string_doc will insert some javascript to
make sub-lists fold/unfold on click (this is useful to display very large
trees compactly and exploring them incrementally).