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On 23/02/17 01:46 PM, Soni L. wrote:



On 23/02/17 01:44 PM, Soni L. wrote:



On 23/02/17 01:39 PM, Egor Skriptunoff wrote:
On Sun, Feb 19, 2017 at 12:20 AM, Soni L. <fakedme@gmail.com <mailto:fakedme@gmail.com>> wrote: 

    local notnil = require "notnil".notnil

    local function f(x)
      x = notnil ^ x
    end

    assert(pcall(f, 1))
    assert(not pcall(f, nil))
Unfortunately, this is not extendable to chained annotations like the following: 

local function f(x, y, z)
  notnil ^ x ^ y ^ z
  -- do something
end

due to right-associativity of "annotation operator"
Fortunately, that's a syntax error anyway. And what was it supposed to return? x? y? z? It can't return all 3.
And keep in mind, right-associativity is what lets you chain annotations in the first place. 



Let's say you want a typechecked annotation, using typecheck[1]:
local myann = apow.annotation ^ typecheck.checked ^ function(self, target) end
Not that this particular case is useful (it'll return nil if there's a type error, but won't return an error message), but you wouldn't be able to do this with left-associativity. 

[1] http://marc.info/?l=lua-l&m=148755896416687&w=2

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