# Infix macros and tuple valued function broadcasting
**URL:** https://discourse.julialang.org/t/infix-macros-and-tuple-valued-function-broadcasting/33002
**Category:** General Usage
**Tags:** question, proposal
**Created:** [January 5, 2020, 7:22pm UTC](https://discourse.julialang.org/t/infix-macros-and-tuple-valued-function-broadcasting/33002 "2020-01-05T19:22:29Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@Jakub\_Wronowski](https://discourse.julialang.org/u/Jakub_Wronowski)
#### Post date: [January 5, 2020, 7:22pm UTC](https://discourse.julialang.org/t/infix-macros-and-tuple-valued-function-broadcasting/33002/1 "2020-01-05T19:22:29Z")
Hello 🙂
I am using modular arithmetic extensively and there are two things that I am missing:
1. Possibility to define infix macro. I’d like to use syntax like this:
> x = H .\* Y @mod 17
and @mod macro would translate the whole expression to
> x = mod.(H .\* Y, 17)
1. Broadcasting functions that return tuples should return tuple of array, not array of tuples
> julia\> A = [2,4,5];
> julia\> x = divrem.(A, 3)
> 3-element Array{Tuple{Int64,Int64},1}:
> (0, 2)
> (1, 1)
> (1, 2)
I’d prefer to use syntax like this:
> x, r = divrem.(A, 3)
It’s not a big deal, cause i can do:
> x, r = div.(A, 3), rem.(A, 3)
Anyway, tuple of arrays make more sense for me here and I am not the only one bothered by this behaviour: [Bug with divrem?](https://discourse.julialang.org/t/bug-with-divrem/3976)
---
### Author:  [@longemen3000](https://discourse.julialang.org/u/longemen3000)
#### Post date: [January 5, 2020, 8:01pm UTC](https://discourse.julialang.org/t/infix-macros-and-tuple-valued-function-broadcasting/33002/2 "2020-01-05T20:01:59Z")
Welcome to JuliaLang Discourse!
In the first one, what about broadcasting `%`?
```julia
x=[30, 31,32]
x .% 17
```
About the second one, broadcasting spits a result of similar size as the input, so giving two arrays comes against this. Maybe using an alternative option?
```julia
a1 = similar(x)
a2 = similar(x)
for i in eachindex(x)
a1[i], a2[i] =divrem(x[i], 17)
end
```
---
### Author:  [@Jakub\_Wronowski](https://discourse.julialang.org/u/Jakub_Wronowski)
#### Post date: [January 5, 2020, 8:20pm UTC](https://discourse.julialang.org/t/infix-macros-and-tuple-valued-function-broadcasting/33002/3 "2020-01-05T20:20:55Z")
Hi @longemen3000 , thanks for the answer!
I am afraid that mod and % (rem) are two different mathematical operations - differences occur for negative numbers and it affects algorithms I am working on. I can implement ‘mod’ with ‘rem’, but I want to keep things simple, that’s why I am looking for alternative syntax.
Your answer gave me an idea - I’ll try to define custom infix operator that is doing ‘mod’ and I’ll broadcast result array with it.
The second suggestion is good, cause it scans x array once, probably I will do something similar inside a helper method.
---
### Author:  [@longemen3000](https://discourse.julialang.org/u/longemen3000)
#### Post date: [January 5, 2020, 8:42pm UTC](https://discourse.julialang.org/t/infix-macros-and-tuple-valued-function-broadcasting/33002/4 "2020-01-05T20:42:22Z")
Another option is to use an struct and overload an infix operator,here is a quick draft
```julia
struct Mod <: Integer
n::Int
end
Base.:%(a::Real, b::Mod) = mod(a, b.n)
x .% Mod(17)
```
As a bonus, it looks like your proposal
---
### Author:  [@Jakub\_Wronowski](https://discourse.julialang.org/u/Jakub_Wronowski)
#### Post date: [January 5, 2020, 9:02pm UTC](https://discourse.julialang.org/t/infix-macros-and-tuple-valued-function-broadcasting/33002/5 "2020-01-05T21:02:47Z")
I think it’s confusing to reuse % for ‘mod’.
I found that there are plenty not used infix operator symbols to use, check ‘prec-times’ list.
>
> ⨸(a, b) = mod(a, b)
> A = [-5, 5, 3, -2]
> res = (2 .+ A .\* 2) .⨸ 3
works well for me.
Thanks!
---
### Author:  [@Jakub\_Wronowski](https://discourse.julialang.org/u/Jakub_Wronowski)
#### Post date: [January 5, 2020, 9:17pm UTC](https://discourse.julialang.org/t/infix-macros-and-tuple-valued-function-broadcasting/33002/6 "2020-01-05T21:17:09Z")
And I like the idea of Mod struct. Using operator from ‘prec-plus’ list allows to skip parentheses.
> struct Mod{T\<:Integer} \<: Integer n::T end
> ⧺(a, b::Mod) = mod(a, b.n)
> A = [-5, 5, 3, -2]
> res = 2 .+ A .\* 2 .⧺Mod(3)