Re: about the next version

[Roberto Ierusalimschy <roberto@...>]

> Perhaps I missed something, or compability isn't a concern: (?)

It is. Our idea is to provide a compatibility file, in Lua, that build
the old library on top of the new one. Most of its work is simply renaming:

   sin = math.sin
   cos = math.cos
   ...

A few functions need a real "implementation". Follows attached a sketch of
this file.

-- Roberto

-------------------------------------------------------------------
-- Real globals
-- _ALERT
-- _ERRORMESSAGE
-- _VERSION
-- _G
-- assert
-- error
-- metatable
-- next
-- print
-- require
-- tonumber
-- tostring
-- type
-- unpack

-------------------------------------------------------------------
-- collectgarbage
-- gcinfo

-- globals

-- call   -> protect(f, err)
-- loadfile
-- loadstring

-- rawget
-- rawset

-- getargs = Main.getargs ??


function do_ (f, err)
  if not f then print(err); return end
  local a,b = pcall(nil, f)
  if not a then print(b); return nil
  else return b or true
  end
end

function dostring(s) return do_(loadstring(s)) end
function dofile(f) return do_(loadfile(f)) end

-------------------------------------------------------------------
-- Table library
foreach = tab.foreach
foreachi = tab.foreachi
getn = tab.getn
tinsert = tab.insert
tremove = tab.remove
sort = tab.sort

-------------------------------------------------------------------
-- Debug library
debug = dbg.debug
getinfo = dbg.getinfo
getlocal = dbg.getlocal
setcallhook = dbg.setcallhook
setlinehook = dbg.setlinehook
setlocal = dbg.setlocal

-------------------------------------------------------------------
-- math library (change to radians?)
abs = math.abs
acos = math.acos
asin = math.asin
atan = math.atan
atan2 = math.atan2
ceil = math.ceil
cos = math.cos
deg = math.deg
exp = math.exp
floor = math.floor
frexp = math.frexp
ldexp = math.ldexp
log = math.log
log10 = math.log10
max = math.max
min = math.min
mod = math.mod
PI = math.pi
--??? pow = math.pow  
rad = math.rad
random = math.random
randomseed = math.randomseed
sin = math.sin
sqrt = math.sqrt
tan = math.tan

-------------------------------------------------------------------
-- string library
strbyte = str.byte
strchar = str.char
concat = str.concat
strfind = str.find
format = str.format
gsub = str.gsub
strlen = str.len
strlower = str.lower
strrep = str.rep
strsub = str.sub
strupper = str.upper

-------------------------------------------------------------------
-- os library
clock = os.clock
date = os.date
difftime = os.difftime
execute = os.execute --?
exit = os.exit
getenv = os.getenv
remove = os.remove
rename = os.rename
setlocale = os.setlocale
time = os.time
tmpname = os.tmpname

-------------------------------------------------------------------
-- compatibility only
local g = globals
getglobal = function (n) return g()[n] end
setglobal = function (n,v) g()[n] = v end

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

local io, tab = io, tab

-- IO library (files)
_STDIN = io.stdin
_STDERR = io.stderr
_STDOUT = io.stdout
_INPUT = io.stdin
_OUTPUT = io.stdout
seek = io.stdin.seek   -- sick ;-)
tmpfile = io.tmpfile
closefile = io.close
openfile = io.open

function flush (f)
  if f then f:flush()
  else _OUTPUT:flush()
  end
end

function readfrom (name)
  if name == nil then
    local f, err, cod = io.close(_INPUT)
    _INPUT = io.stdin
    return f, err, cod
  else
    local f, err, cod = io.open(name, "r")
    _INPUT = f or _INPUT
    return f, err, cod
  end
end

function writeto (name)
  if name == nil then
    local f, err, cod = io.close(_OUTPUT)
    _OUTPUT = io.stdout
    return f, err, cod
  else
    local f, err, cod = io.open(name, "w")
    _OUTPUT = f or _OUTPUT
    return f, err, cod
  end
end

function appendto (name)
  local f, err, cod = io.open(name, "a")
  _OUTPUT = f or _OUTPUT
  return f, err, cod
end

function read (...)
  local f = _INPUT
  if type(arg[1]) == 'userdata' then
    f = tab.remove(arg, 1)
  end
  return f:read(unpack(arg))
end

function write (...)
  local f = _OUTPUT
  if type(arg[1]) == 'userdata' then
    f = tab.remove(arg, 1)
  end
  return f:write(unpack(arg))
end