Patrick R. Michaud a écrit :
I've put together a draft with my ideas and design for
(re-)implementing lexicals in Parrot -- now available at
http://www.pmichaud.com/perl6/lexical.txt .
It's a first draft and might be a bit confusing in places,
but overall I think it's a far cleaner design than the
current implementation but also handles the vast bulk of
what we need (or can be made to do so easily).
Anyway, comments greatly appreciated.
Currently, the bigger issue in Lua on Parrot is lexical or upvalue in
Lua jargon (the reason for Lua on Parrot is not really Lua).
The following Lua code doesn't give the expected result (from
languages/lua/t/closure.t) :
a = {}
local x = 20
for i=1,10 do
local y = 0
a[i] = function () y=y+1; return x+y end
end
print(a[1]())
print(a[1]())
print(a[2]())
--[[
The loop creates ten closures (that is, ten instances of
the anonymous function). Each of these closures uses
a different y variable, while all of them share the same x.
]]
With the current Parrot, I never found a way to do it.
So, I'll be happy if this revisiting handles this issue.
François.
Pm
