Re: Numeric for loop with rationals

["Soni \"They/Them\" L." <fakedme@...>]

On 2018-01-30 12:48 PM, Charles Heywood wrote:
> I am confused on why you think you can't:
>
> Lua 5.3.4  Copyright (C) 1994-2017 Lua.org, PUC-Rio
> > function one() return 1 end
> > function two() return 2 end
> > function ten() return 10 end
> > for i=one(), ten(), two() do print(i) end
> 1
> 3
> 5
> 7
> 9
> >

Lua 5.3.4  Copyright (C) 1994-2017 Lua.org, PUC-Rio
> meta = {__add=function(x, y) return setmetatable({i=x.i + y.i}, meta) 
end, __lt=function(x, y) return x.i < y.i end}
> function one() return setmetatable({i=1}, meta) end
> function two() return setmetatable({i=2}, meta) end
> function ten() return setmetatable({i=10}, meta) end
> for i=one(), two(), ten() do print(i) end
stdin:1: 'for' limit must be a number
stack traceback:
    stdin:1: in main chunk
    [C]: in ?
> local i,j,k=one(), ten(), two() while i < j do print(i) i = i + k end
table: 0x558de8c74080
table: 0x558de8c74200
table: 0x558de8c747b0
table: 0x558de8c74890
table: 0x558de8c74970
> local i,j,k=one(), ten(), two() while i < j do print(i.i) i = i + k end
1
3
5
7
9

Rationals don't work. Only floats and ints do. This sucks.

> On Tue, Jan 30, 2018 at 7:08 AM Soni "They/Them" L. <fakedme@gmail.com 
> <mailto:fakedme@gmail.com>> wrote:
>
>
>
>     On 2018-01-30 11:04 AM, Dirk Laurie wrote:
>     > 2018-01-30 14:55 GMT+02:00 Soni "They/Them" L.
>     <fakedme@gmail.com <mailto:fakedme@gmail.com>>:
>     >>
>     >> On 2018-01-30 10:51 AM, Dirk Laurie wrote:
>     >>> 2018-01-30 14:23 GMT+02:00 Soni "They/Them" L.
>     <fakedme@gmail.com <mailto:fakedme@gmail.com>>:
>     >>>>
>     >>>> On 2018-01-30 06:58 AM, Francisco Olarte wrote:
>     >>>>> On Tue, Jan 30, 2018 at 1:11 AM, Soni "They/Them" L.
>     <fakedme@gmail.com <mailto:fakedme@gmail.com>>
>     >>>>> wrote:
>     >>>>> ...
>     >>>>>> Also, rationals are still numbers. They're just not "Lua
>     numbers"
>     >>>>>> (objects
>     >>>>>> with type(x) == "number"). Any language with operator
>     overloading (e.g.
>     >>>>>> C++)
>     >>>>>> lets me have numeric for with rationals. Except Lua.
>     (Python doesn't
>     >>>>>> have
>     >>>>>> numeric for at all so it doesn't count.)
>     >>>>> C++ does not have numeric for, so it doesn't count either.
>     >>>>>
>     >>>>> Francisco Olarte.
>     >>>>>
>     >>>> for (int i = 0; i < 100; i++) { printf("%d\n", i); }
>     >>>>
>     >>>> Looks like it does, it's just more flexible than Lua's.
>     >>> No 'for' is more flexible than Lua's.
>     >>>
>     >>> for a,b,c,as_many_as_you_like in myiter(anything) do
>     >>> end
>     >>>
>     >> Sorry, C++'s numeric for is more flexible than Lua, because it
>     gives you
>     >> more control over the iteration.
>     >>
>     >> You can also use rational objects which overload < and ++ in
>     C++ numeric
>     >> fors, while you can't in Lua even with __add and __lt.
>     > C/C++ does not have a numeric for, it only has a generic for.
>     >
>     > for (statement_list_1;statement_list_2;statement_list_3) do
>     statement;
>     >
>     > Nothing numeric about that.
>     >
>     > No restriction anywhere, although if statement_list_2 is just an
>     > assignment most compilers will recommend that you put it in
>     > parentheses.
>     >
>
>     We can argue about this all day but if I can do, in C++
>
>     for (type i = min; i < max; i += step) {
>     }
>
>     Why can't I do
>
>     for i=min,max,step do
>     end
>
>     in Lua? They should be equivalent.
>
>     --
>     Disclaimer: these emails may be made public at any given time,
>     with or without reason. If you don't agree with this, DO NOT REPLY.
>
>
> --
> --
> Ryan | Charles <vandor2012@gmail.com <mailto:vandor2012@gmail.com>>
> Software Developer / System Administrator
> https://hashbang.sh

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