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Patrick Donnelly <batrick@batbytes.com> wrote:
> For some slightly early "It's Friday" discussion, what do you use the
> __call metamethod for? Discuss your favorite hacks, strange problems
> solved, code golf hole-in-ones, etc.
Here’s one that somebody suggestsed for a module of mine. The module is
named split, and the primary method is also split. So if you require it in
a conventional way, you get this:
local split = require "split"
local record = "foo,bar,bizz,buzz"
local fields = split.split(record)
To avoid the redundancy, he suggested packaging the module this way:
return setmetatable({
split = split;
-- various other methods
},{
__call = function(_, ...)
return split(...)
end
})
So now a user can require the module as normal, but call split using the
module alone. I didn’t do it at the time—I thought that it was too magic
and unnecessary since it’s easy for a user to assign the method to whatever
short name they like when they require the module.
But now I’m curious: is this pattern common in other Lua modules? I don’t
think I’ve seen it, but perhaps I haven’t seen enough.
Best, P
--
We have not been faced with the need to satisfy someone else's
requirements, and for this freedom we are grateful.
Dennis Ritchie and Ken Thompson, The UNIX Time-Sharing System