Re: _SELF and _SUPER
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- Subject: Re: _SELF and _SUPER
- From: Duane Leslie <parakleta@...>
- Date: Sun, 7 Aug 2016 19:53:46 +1000
> On 7 Aug 2016, at 06:36, Sean Conner <sean@conman.org> wrote:
>
> It was thus said that the Great Soni L. once stated:
>>
>>> On 06/08/16 05:30 PM, Sean Conner wrote:
>>> You just need a Y-combinator:
>>>
>>> function Y(f)
>>> local function g(...) return f(g,...) end
>>> return g
>>> end
>>>
>>> print(Y(function(rec, x)
>>> if x < 2 then
>>> return 1
>>> else
>>> return x * rec(x-1)
>>> end
>>> end)(5))
>>>
>>> That will allow you to call an anonymous function recurively from within
>>> the anonymous function. No need for _SELF in this case.
>>
>> That doesn't solve the dynamic variable indexing issue.
>
> Oh, I'm sorry I failed to read your mind again. I thought that was what
> _SUPER was for. I'm so sorry you have to reject MY ATTEMPT to give you
> something you could use and grovel that I have to have your proposal
> explained to me like I'm five.
>
> -spc (Why do I even bother?)
I appreciated the explanation. I like learning ways to 'upgrade' a language with clever syntactic sugar without having to change the underlying language. It gives the option to use much more powerful paradigms within a simpler language.
I personally think this _SELF/_SUPER thing comes unravelled with the requirement that it support dynamic variable lookups. That adds an overhead to the runtime which I don't agree with. If it was only statically declared lookups then it could be easily implemented as a custom parser that would actually generate standard byte-code.
I miss that metalua didn't make the jump to 5.2/5.3, I'm often tempted to bring it up to date but for now I still find it easier to just modify the parser directly. I think if metalua was current a lot of these feature requests could just be resolved with a metalua script.