Re: Microlight
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- Subject: Re: Microlight
- From: "Pierre Chapuis" <catwell@...>
- Date: 2012年12月18日 16:13:42 +0100
> And everything because you want to write:
>
> map( filter( t, is_odd ), function( _, v ) print( v ) end )
>
> instead of:
>
> for i,v in ipairs( t ) do
> if is_odd( i ) then
> print( v )
> end
> end
I don't know about others but that is probably not a case where I would
use map.
To me things like map and filter come from functional programming and
should behave like functional programming, i.e. operate on a list,
return a list, not modify their input and not have side effects.
My usual implementation of map is this:
local map = function(f,t)
local r = {}
for i=1,#t do r[i] = f(t[i]) end
return r
end
and I use it in cases like this:
local path = table.concat(map(tostring,table),"/")
instead of:
local temp = {}
for i=1,#table do temp[i] = tostring(table[i]) end
local path = table.concat(temp,"/")
Similarly filter would probably not operate on the keys of an
associative array but on the values of a list.
That being said I agree that these primitives are being abused a lot in
Lua. Its style is mostly imperative, embrace it or use a Lisp...
--
Pierre Chapuis