Create the following as Module:Foo:
local p, mt = {}, {}
function mt.__call(t, frame)
return 'Hello from the __call metamethod'
end
p.main = setmetatable({}, mt)
return pFrom the sandbox, =p.main(mw.getCurrentFrame()) correctly displays "Hello from the __call metamethod". From wikitext, however, {{#invoke:Foo|main}} displays a script error that p.main isn't a function.
Version: unspecified
Severity: trivial
What would be the advantage of allowing #invoke to call a table via the __call metamethod, instead of just using a function?
Functions seem like they would be much less confusing to on-wiki module authors than tables-that-can-be-called.
Take this module, for example:
local p = {}
p.continents = {
na = { area = 24490000, pop = 542056000 },
sa = { area = 17840000, pop = 392555000 },
antarctica = { area = 13720000, pop = 4490 }
}
p.oceans = {
atlantic = { area = 82400000, volume = 323600000 },
pacific = { area = 165250000, volume = 714000000 }
}
local mt = {}
function mt.__call(t, frame)
for _,v in ipairs(frame.args) do
t = t[v]
end
return t
end
for _,v in pairs(p) do
setmetatable(v, mt)
end
return p
This module allows other modules to retrieve data via "foo = p.continents.na.area", and wikitext to retrieve data via "{{#invoke:Foo|continents|na|area}}".
OTOH, you could as easily write that with a function getContinent, and at the same time avoid confusing people into thinking they could do "{{#invoke:Foo|bar|baz}}" for any random table that is included in 'p'.
For that matter, returning random tables in 'p' may not be the greatest idea; see bug 48393 for example.