Convert Lua source to a C file

#!/usr/bin/env lua

----- lua 5.1 script to convert a lua file into a C file
-----
----- Usage: lua2c foo.lua > lfoo.c     # compiled, so not portable
-----        lua2c -s foo.lua > lfoo.c  # source, and so portable


---------------- general utility functions -------------

function io.contents(filename)
  local f, msg = io.open(filename, 'r')
  if not f then return f, msg end
  local s = assert(f:read '*a')
  f:close()
  return s
end

function os.capture(cmd, raw)
  local f = assert(io.popen(cmd, 'r'))
  local s = assert(f:read('*a'))
  f:close()
  if raw then return s end
  s = string.gsub(s, '^%s+', '')
  s = string.gsub(s, '%s+$', '')
  s = string.gsub(s, '[\n\r]+', ' ')
  return s
end

local quote_me = '[^%w%+%-%=%@%_%/]'
                     -- easier to complement what doesn't need quotes
local strfind = string.find

function os.quote(s)
  if strfind(s, quote_me) or s == '' then
    return "'" .. string.gsub(s, "'", [['"'"']]) .. "'"
  else
    return s
  end
end

function os.runf(...) return os.execute(string.format(...)) end

-------------------------------------------------------
local lua -- program to be loaded (source or binary)

local libname

if arg[1]:find '^-lib' and arg[2] then
  libname = arg[2]
  table.remove(arg, 1)
  table.remove(arg, 1)
end


if arg[1] == '-a' or arg[1] == '-s' then -- don't compile;
                                     -- use ascii source
  table.remove(arg, 1)
  assert(#arg == 1)
  lua = io.contents(arg[1]):gsub('^#!.-\n', '')
else
  assert(#arg == 1)
  local bin = os.capture 'PATH=/bin:$PATH tempfile'
  assert(os.runf('luac -o %s %s', os.quote(bin), os.quote(arg[1])) == 0)
  lua = io.contents(bin)
  os.remove(bin)
end

libname = libname or arg[1]:gsub('.*/', ''):gsub('%.lua$', '')

outfile = io.stdout

------------------------

outfile:write [[
#include <lua.h>
#include <lauxlib.h>

static unsigned char program[] = {
]]

outfile:write '  '

local function printf(...) return outfile:write(string.format(...)) end

local last = lua:len()

for i = 1, last do
  local n = string.byte(lua, i)
  printf('%3d%s', n, i < last and ', ' or '')
  if i % 10 == 0 then printf '\n  ' end
end

printf '\n};\n\n'

outfile:write((([[

int luaload_$lib(lua_State *L) {
  return luaL_loadbuffer(L, (const char*)program, sizeof(program), "@$source");
}

int luaopen_$lib(lua_State *L) {
  if (luaL_loadbuffer(L, (const char*)program, sizeof(program), "@$source"))
    return luaL_error(L, "Internal library '%s' failed to parse", "$lib");
  if (lua_pcall(L, 0, 1, 0))
    return luaL_error(L, "Internal library '%s' failed to run: %s", "$lib",
                      lua_tostring(L, -1));
  if (lua_isnil(L, -1)) {
    lua_pop(L, 1);
    lua_pushboolean(L, 1);
  }
  lua_getglobal(L, "package");   // s: lib package
  lua_getfield(L, -1, "loaded"); // s: lib package loaded
  lua_remove(L, -2);             // s: lib loaded
  lua_pushstring(L, "$lib");     // s: lib loaded libname
  lua_pushvalue(L, -3);          // s: lib loaded libname lib
  lua_settable(L, -3);           // s: lib loaded
  lua_pop(L, 1);                 // s: lib
  return 1;
}
]]):gsub('$(%a+)', { lib = libname, source = arg[1]:gsub('.*/', '') })))