lib/readline.nit

   1 # This file is part of NIT (http://www.nitlanguage.org).
   2 #
   3 # Copyright 2016 Frédéric Vachon <fredvac@gmail.com>
   4 #
   5 # Licensed under the Apache License, Version 2.0 (the "License");
   6 # you may not use this file except in compliance with the License.
   7 # You may obtain a copy of the License at
   8 #
   9 #     http://www.apache.org/licenses/LICENSE-2.0
  10 #
  11 # Unless required by applicable law or agreed to in writing, software
  12 # distributed under the License is distributed on an "AS IS" BASIS,
  13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14 # See the License for the specific language governing permissions and
  15 # limitations under the License.
  16
  17 # GNU readline library wrapper
  18 module readline is ldflags "-lreadline"
  19
  20 in "C" `{
  21         #include <readline/readline.h>
  22         #include <readline/history.h>
  23 `}
  24
  25 private fun native_readline(prompt: NativeString): NativeString `{
  26         return readline(prompt);
  27 `}
  28
  29 private fun native_add_history(data: NativeString) `{
  30         if (data == NULL) return;
  31         add_history(data);
  32 `}
  33
  34 # Set emacs keybindings mode
  35 fun set_vi_mode `{ rl_editing_mode = 0; `}
  36
  37 # Set emacs keybindings mode
  38 fun set_emacs_mode `{ rl_editing_mode = 1; `}
  39
  40 # Use the GNU Library readline function
  41 # Returns `null` if EOF is read
  42 # If `with_history` is true, it will save all commands in the history except
  43 # empty strings and white characters strings
  44 fun readline(message: String, with_history: nullable Bool): nullable String do
  45         var line = native_readline(message.to_cstring)
  46         if line.address_is_null then return null
  47
  48         var nit_str = line.to_s
  49
  50         if with_history != null and with_history then
  51                 if nit_str.trim != "" then native_add_history(line)
  52         end
  53
  54         return nit_str
  55 end
  56
  57 # Adds the data String to the history no matter what it contains
  58 fun add_history(data: String) do native_add_history data.to_cstring