not for the faint of heart

regexes.d

import std.file, std.regex, std.stdio, std.string;

void main(string[] args)
{
  if (args.length != 2)
    return ;

  auto text = readText(args[1]);

  /+
    opening brace setup
  +/
  enum opening_brace_pattern = `((?:%-(%s|%))[^\n]*)\n\t*\{`;

  enum opening_brace_with_newline_keywords    = ["func", "for" ];
  enum opening_brace_without_newline_keywords = ["if"  , "else"];

  enum opening_brace_with_newline_Regex    = regex(format(opening_brace_pattern, opening_brace_with_newline_keywords   ));
  enum opening_brace_without_newline_Regex = regex(format(opening_brace_pattern, opening_brace_without_newline_keywords));

  /+
    opening brace regex
  +/
  text = replaceAll(text, opening_brace_with_newline_Regex,    "$1 {\n");
  text = replaceAll(text, opening_brace_without_newline_Regex, "$1 {  ");

  /+
    one line setup
  +/
  enum one_line_if_regex   = regex(`(if[^{\n]*)\n([^\n]+)(\n{2}\t+)else`);
  enum one_line_else_regex = regex(`(else[^{\n]*)\n([^\n]+)\n(\t+)\}`   );

  /+
    one line regex
  +/
  text = replaceAll(text, one_line_if_regex,   "$1 {\n$2\n$3} else"  );
  text = replaceAll(text, one_line_else_regex, "$1 {\n$2\n$3\t}\n$3}");

  write(text);
  File(format("%s2.go", args[1][0 .. $ - 3]), "w").write(text);
}