Metalua: adding runtime type-checking in Lua, a tutorial

[Fabien <fleutot+lua@...>]

Hi,

A new Meatlua tutorial is available, which shows through a concrete example how to write a language extension. It introduces runtime type-checking into Metalua, allowing to write things such as:

----------------------------------
function sum (x :: list(number)) :: number
  local s = 0
  for _, n in ipairs (x) do s = s + n end
  return s
end

list = {1, 2, 3, 4, 5}
list_sum = sum (list)
print ("Sum value:", list_sum)
----------------------------------

(I chose '::' rather than ':', because I really wasn't interested into handling ambiguities between type assertions and method invocations)

The tutorial is available at 
http://luaforge.net/docman/view.php/227/164/tutorial.typecheck.pdf, and the corresponding sources at http://luaforge.net/docman/view.php/227/165/tutorial.typecheck.src.tgz

Feedbacks welcome.

-- 
Fabien Fleutot
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