Re: Default parameter values
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- Subject: Re: Default parameter values
- From: dyngeccetor8 <dyngeccetor8@...>
- Date: Sat, 2 Dec 2017 14:23:49 +0300
On 11/30/2017 02:37 PM, Dirk Laurie wrote:
> Does a patch that allows the clumsy idiom
>
> function(a,b,c)
> a = a or 0
> c = c or 1
>
> to be replaced by
>
> function(a=0,b,c=1)
>
> already exist?
>
Well, if I was frustrated I'd try to write wrapper function for such things:
local wrap =
function(f, defaults)
-- assert_function(f)
-- assert_table(defaults)
local result =
function(...)
local args = table.pack(...)
local n = math.max(args.n, defaults.n)
for i = 1, n do
args[i] = args[i] or defaults[i]
end
return f(table.unpack(args, 1, n))
end
return result
end
local core =
function(a, b, c)
print(a, b, c)
end
local wrapped_core = wrap(core, {0, nil, 1, n = 3})
wrapped_core()
-- Martin