Re: On adding type information to a dynamically typed language

[Ulrich Schmidt <u.sch.zw@...>]

Am 20.09.2017 um 13:28 schrieb Luiz Henrique de Figueiredo:
> local types = {
> "nil", "boolean", "number", "string", "table", "function", "userdata", "thread",
> }
>
> is = {}
>
> for _,t in pairs(types) do
> 	is[t] = function (v)
> 			if type(v)~=t then
> 				error(t.." expected, got "..type(v),2)
> 			end
> 			return v
> 		end
> end
>
> function f() end
> x=2
> s="a"
> s=2
> f (is.number (x), is.string (s))

I like it! But i still i dont like any prefix solution / funtion call 
for this task. I would like to write in my sources something like:
  f(x.string(), y.number())
or better:
  f(x.string, y.number)
hence we have to modify the metatables for all data types. Each 
metatable needs only 1 method: string() for string metatable, number() 
for number metatable and so on. This function should return the value 
itself. If i call for instance x.string() on a number value, the method 
is undefined and a error is raised.

May be i dont see the drawbacks of this idea?

Ulrich.