Re: proposal: state machine syntax also usable for continue /nested break
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- Subject: Re: proposal: state machine syntax also usable for continue /nested break
- From: "Stuart P. Bentley" <stuart@...>
- Date: 2011年1月28日 01:08:08 -0800
?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