Re: proposal: state machine syntax also usable for continue /nested break

["Stuart P. Bentley" <stuart@...>]

?What about a loop like this one:

for _,vv in pairs(t) do
   for _,v in pairs(vv) do
       break :_: end
   end
end

As much as I hate magic-ing up the declaration of local variables (allowing 
you to break to the next statement after the local was declared?), re-using 
those semantics would make the answer pretty clear (the inner one). The 
downside here is that you wouldn't be able to refer ahead to labels (since 
locals aren't visible before they're declared), but you could fake it:

for i=1,100 do
 local continue=false
 if not continue then
   --snip loop content--
   --continue scenario
   continue=true
   break i
 end
end

-----Original Message----- 
From: David Manura
Sent: Thursday, January 27, 2011 9:09 PM Newsgroups: 
gmane.comp.lang.lua.general
To: Lua mailing list
Subject: Re: proposal: state machine syntax also usable for continue /nested 
break

On Fri, Jan 28, 2011 at 12:03 AM, David Manura <dm.lua@math2.org> wrote:
> I don't local variables can completely replace labels in the above
> proposal (as opposed to [1]).  However, my above suggestion for
> implicitly naming variables could incorporate the loop variable name
> in the label.  Therefore, :forfor: could be replaced with :kk: .

err, correction: don't -> don't think; naming variables -> naming
labels.  In other words, this would be consistent with the proposed
semantics:

for kk, vv in pairs(tt) do
  for k, v in pairs(t) do
    if condition1 then break end    -- same as `break :k:`
    if condition2 then break :continue: end
    if condition3 then break :redo: end
    if condition4 then break :kk: end
  end
end