Re: [Lua-users-stdlib] Upheaval (blame Jamie Webb!)

[Jamie W. <j...@jm...>]

On Monday 02 February 2004 10:29, Reuben Thomas wrote:
> > Naming: yeah, dunno. Arity: I decided it made sense only for commutative
> > operators to be variadic.
>
> Whereas in e.g. APL they all are, and you get alternating differences with
> -. I'm not sure what's worse: providing variadic / (what is that for?) or
> not providing it (why doesn't my code work suddenly when I replace + with
> /?).

How about:

["/"] = function(a,b,c) assert(c == nil, "/ is binary only") return a/b end

At least you get a meaningful error that way.

> Seems a bit contrived. If you wanted those that had attribute foo < 4,
> you'd still need to make a function.

small = std.filter(std.compose(std.bind(std.op[">"], 4), std.getter("foo")), 
objects)

Seriously though, I realise it's not very general, but I have found it useful. 
I suppose it just depends on how large you want the library to end up.

> > Say I want to call method swizzle(5) on each of a list of (maybe
> > polymorphic) objects:
> >
> > results = std.map(std.method("swizzle", 5), objects)
>
> And again, that only works with constant values. If you wanted to call
> swizzle(self.foo+self.bar), again, you'd need a function.

method() is to methods what bind() is to functions (bind_method() lies 
somewhere in the middle). I don't see how you can claim that one is useful 
but not the other. Personally, I use them both about equally, and from my 
libary use only map() more frequently.

If I wanted self.foo+self.bar, then yes, I'd probably write a function (or 
make a swizzle_foo_bar() method). But in general where the values are not 
constant:

results = std.map(std.method("swizzle"), objects, params)

 -- Jamie Webb