Re: orif
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- Subject: Re: orif
- From: Sean Conner <sean@...>
- Date: 2015年8月14日 19:42:28 -0400
It was thus said that the Great Soni L. once stated:
> (Copypasted from
> https://gist.github.com/SoniEx2/99882fa8d5a0740339b0#the-orif-idea )
>
> The orif Idea
> =============
>
> orif (possible operators: `|if`, `orif`, `or if`, ...) is a construct that
> allows if statements with **explicit** fall-through.
It's an interesting idea, but I'm still unsure if I like the name "orif"
or not. I don't really like it, but I can't come up with a better name.
But, if it's a switch with a fallthrough case you are missing (and
frankly, I really haven't missed it that much in Lua), what about the
following?
-- ----------------------------
-- You need this function
-- ----------------------------
function switch(key,case,otherwise)
otherwise = otherwise or function() return nil end
if not case[key] then
return otherwise(case,key)
else
return case[key](case,key)
end
end
-- ----------------------------
-- And now you can do this
-- ----------------------------
flag = false
i = 2
switch(i,
{
function() flag = true end,
function(case) case[1]() print(flag) end,
},
function() print "Unknown!" end
)
It's about the same syntatical overhead of a C or Java switch statement,
but it does allow fallthrough (or the effect thereof). And it can be used
in an expression context (take THAT, C!).
-spc (Did not expect this to be so easy ... )