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- Subject: Re: Why do we have ipairs?
- From: Sean Conner <sean@...>
- Date: Wed, 25 Jun 2014 13:21:03 -0400
It was thus said that the Great David Demelier once stated:
> Le 11 juin 2014 10:30, "Axel Kittenberger" <axkibe@gmail.com> a écrit :
> >
> > But a switch statement in most script languages (like in Javascript) is
> syntactic sugar for if/else! That has always been the argument from the Lua
> team to why there is no switch statement in Lua. Not like for example in C
> where it is in fact a computed goto.
> >
>
> Unfortunately it still does not explain why there is no continue in Lua but
> break exists. This is one of my major hate.
This is a topic that pops up from time to time, such as back in 2010:
http://lua-users.org/lists/lua-l/2010-02/msg00491.html
The result seems to be that continue in the presence of repeat/until is
undefined. The example given:
repeat
if cond then continue end
local t = 1
...
until t == 4
"continue" will skip ahead to the conditional, but when cond is true, then t
is undefined (locals in the repeat/until scope don't go out of scope until
after the until statement). You might say that's okay, t returns nil, but
what about this?
repeat
if cond then continue end
x = { y = { t = 1 }
...
until x.y.t == 4
you'll error out with an undefined reference (contrived, yes). That was
apparently enough of a concern to keep continue out of Lua.
-spc
- References:
- Re: Why do we have ipairs?, Coda Highland
- Re: Why do we have ipairs?, Thiago L.
- Re: Why do we have ipairs?, Daurnimator
- Re: Why do we have ipairs?, Thiago L.
- Re: Why do we have ipairs?, Axel Kittenberger
- Re: Why do we have ipairs?, Jay Carlson
- Re: Why do we have ipairs?, Axel Kittenberger
- Re: Why do we have ipairs?, Andrew Starks
- Re: Why do we have ipairs?, Axel Kittenberger
- Re: Why do we have ipairs?, David Demelier