Re: Why do we have ipairs?

[Axel Kittenberger <axkibe@...>]

But a switch statement in most script languages (like in _javascript_) is syntactic sugar for if/else! That has always been the argument from the Lua team to why there is no switch statement in Lua. Not like for example in C where it is in fact a computed goto.

On Wed, Jun 11, 2014 at 10:23 AM, Andrew Starks <andrew.starks@trms.com> wrote:

On Wed, Jun 11, 2014 at 1:42 AM, Axel Kittenberger <axkibe@gmail.com> wrote:

Iterators are not bound to for loops.

for k, v in ipairs( t )

do

    print(k, v )

end

is syntactic sugar for:

local it = ipairs( t )

local k, v = it( t, 0 )

while k ~= nil

do

    print(k, v )

    k, v = it( t, k )

end

is syntactic sugar for:

local it = ipairs( t )

local k, v

k, v = it( t, 0 )

::loop::

print(k, v )

k, v = it( t, k )

if( k ~= nil )

then

    goto loop

end

I think that in order for one thing to be the "syntactic sugar" of another, they need to do the same thing, not just have the same outcome. A switch statement wouldn't be sugar for an if/else. A "repeat until" loop isn't sugar for a while loop or a for loop. They over lap, and perhaps one can do without the other if at least one is present. They are not sugar.

Examples of sugar:

local x

x = function(...)

 --do stuff

  return x(...)

end

--is sugar for

local function x(...)

 ...

`local x:y(args)` is sugar for `local x.y(x, args)` 

`{ foo = "bar"}` is sugar for `{ ["foo"] = "bar"}`

--Andrew