ext_pp.ml

(* OCamlScript compiler
 * Copyright (C) 2015-2016 Bloomberg Finance L.P.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, with linking exception;
 * either version 2.1 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *)

(* Author: Hongbo Zhang  *)



module L = struct 
  let space = " "
  let indent_str = "  "
end

let indent_length = String.length L.indent_str 

type t = {
  output_string : string -> unit;
  output_char : char -> unit; 
  flush : unit -> unit;
  mutable indent_level : int;
  mutable last_new_line : bool; 
  (* only when we print newline, we print the indent *)
}

let from_channel chan = { 
  output_string = (fun  s -> output_string chan s); 
  output_char = (fun c -> output_char chan c);
  flush = (fun _ -> flush chan);
  indent_level = 0 ;
  last_new_line = false;
}


let from_buffer buf = {
  output_string = (fun s -> Buffer.add_string buf s);
  output_char = (fun  c -> Buffer.add_char buf c);
  flush = (fun _ -> ());
  indent_level = 0;
  last_new_line = false;
}

(* If we have [newline] in [s], 
   all indentations will be broken 
   in the future, we can detect this in [s]
 *)
let string t s = 
  t.output_string  s ;
  t.last_new_line <- false

let newline t = 
  if not t.last_new_line then 
    begin
      t.output_char  '\n';
      for i = 0 to t.indent_level - 1 do 
        t.output_string  L.indent_str;
      done;
      t.last_new_line <- true
    end

let force_newline t = 
  t.output_char  '\n';
  for i = 0 to t.indent_level - 1 do 
    t.output_string  L.indent_str;
  done

let space t  = 
  string t L.space

let group t i action = 
  if i = 0 then action ()
  else 
    let old = t.indent_level in
    t.indent_level <- t.indent_level + i;
    Ext_pervasives.finally () action (fun _ -> t.indent_level <- old)

let vgroup = group

let paren t action = 
  string t "(";
  let v = action () in
  string t ")";
  v 

let brace fmt u = 
  string fmt "{";
  (* break1 fmt ; *)
  let v = u () in
  string fmt "}";
  v 

let bracket fmt u = 
  string fmt "[";
  let v = u () in
  string fmt "]";
  v 

let brace_vgroup st n action = 
  string st "{";
  let v = vgroup st n (fun _ -> 
    newline st; 
    let v =  action () in
    v
              ) in
  force_newline st;
  string st "}";
  v

let bracket_vgroup st n action = 
  string st "[";
  let v = vgroup st n (fun _ -> 
    newline st; 
    let v =  action () in
    v
              ) in
  force_newline st;
  string st "]";
  v

let bracket_group st n action = 
  group st n (fun _ -> bracket st action)

let paren_vgroup st n action = 
  string st "(";
  let v = group st n (fun _ -> 
    newline st; 
    let v = action () in
    v
                     ) in
  newline st;
  string st ")";
  v 
let paren_group st n action = group st n (fun _ -> paren st action)

let brace_group st n action = 
  group st n (fun _ -> brace st action )

let indent t n = 
  t.indent_level <- t.indent_level + n 

let flush t () = t.flush ()