write gcc preprocessed headers to lua module

ffipp.lua

#!/usr/bin/luajit
--[[
ffipp
David Hollander 2012
MIT License
Preprocess C Headers into LuaJIT modules
]]

local CMD = 'gcc -E'
local BASE = '/usr/include/'
local HEAD = '--[[\nGenerated by ffipp at '..os.date('%H:%M %Y.%m.%d')..' '..'\n'
local HEAD2 = ']]\nlocal ffi = require "ffi"\nffi.cdef[[\n'
local TAIL = ']]\n'
local FILTER = function(line) return line end --line:gsub('^%s+','') end
local ti, tc = table.insert, table.concat

local function dump(des, ...)
  local list, set = {...}, {}
  assert(#list>0, 'ffipp: No headers specified')
  for i,v in ipairs(list) do list[i] = BASE..v; set[list[i]] = true end
  local list_str = tc(list, ' ')
  local lua_head = HEAD .. list_str .. '\n' .. HEAD2
  local output = assert(io.open(des,'w'), 'ffipp: Cannot write to: '..des)
  local input = assert(io.popen(CMD..' '..list_str), 'ffipp: Cannot popen: '..CMD)
  output:write(lua_head)

  --local save
  local save = true 
  for l in input:lines() do
    local incsrc = l:match '^#.-"(.-)"'
    if incsrc then --save = set[incsrc]
    elseif save and l~='' then output:write(FILTER(l),'\n') end
  end
  output:write(TAIL)
  output:flush()
  output:close()
end

-- INPUT
--
return (...) and dump(...) or {dump=dump}

Example:
./ffipp out.lua openssl/ssl.h