Re: Syntax addition: with ... do
[
Date Prev][
Date Next][
Thread Prev][
Thread Next]
[
Date Index]
[
Thread Index]
- Subject: Re: Syntax addition: with ... do
- From: Jerome Vuarand <jerome.vuarand@...>
- Date: 2010年1月13日 17:00:29 +0100
2006年9月18日 Hugh O'Byrne <hobyrne@gmail.com>:
> On 9/15/06, Jerome Vuarand <jerome.vuarand@ubisoft.com> wrote:
>>
>> You can try something like that :
>>
>> -- Start of Lua ----------------------------
>> with = function(context)
>> ...
>> end
>>
>> endwith = function()
>> ...
>> end
>>
>> -- You can then write
>> with (object) do
>> name=parent.name..name
>> end
>> endwith()
>>
>> -- End of Lua ------------------------------
>>
>> Globals can still be accessed directly if not overriden in object, or
>> through _G inconditionnaly. Endwith is the only syntactic drawback, you have
>> to explictly restore the environment. As the do/end is not necessary, you
>> can just write:
>>
>> with (object)
>> name=parent.name..name
>> endwith()
>
> Even that could be encapsulated. Something like:
>
> function withblock (context, function)
> with (context)
> function()
> endwith()
> end
>
> used like:
>
> withblock (object, function () name = parent.name..name end)
>
> - Syntax may be a bit rusty, but it's possible to automate the restoration
> of the environment in this way. I guess maybe the identifier 'function' is
> not allowed within function, there may be some other caveats too.
>
> Hugh O'Byrne.
>
>
I'm resurecting an old thread (thanks to Hugh's mail about
netiquette), but the original poster request is now nicely solved by
Lua 5.2 (the keyword being 'in' rather than 'with').