Format the output file for Erlang in a nicer way (#3135)gh-1306

For Erlang, format the output in the same way as the 'S' option
does. To achieve this, we use the `beam_listing` module, which is
undocumented but has been stable for many many years.

1 files changed, 3 insertions, 2 deletions

diff --git a/lib/compilers/erlang.js b/lib/compilers/erlang.js
index aa9ebde3f..31018086c 100644
--- a/lib/compilers/erlang.js
+++ b/lib/compilers/erlang.js
@@ -39,8 +39,9 @@ export class ErlangCompiler extends BaseCompiler {
             '-eval',
             '{ok, Input} = init:get_argument(input),' +
                 '{ok, _, Output} = compile:file(Input, [\'S\', binary, no_line_info, report]),' +
-                'Binary = io_lib:format("~p", [Output]),' +
-                `file:write_file("${outputFilename}", list_to_binary(Binary)),` +
+                `{ok,Fd} = file:open("${outputFilename}", [write]),` +
+                'beam_listing:module(Fd, Output),' +
+                'file:close(Fd),' +
                 'halt().',
         ];
     }