# How to write a macro to export all instances of an enum type
**URL:** https://discourse.julialang.org/t/how-to-write-a-macro-to-export-all-instances-of-an-enum-type/73137
**Category:** General Usage
**Tags:** question, macros, metaprogramming, enum
**Created:** [December 15, 2021, 11:35am UTC](https://discourse.julialang.org/t/how-to-write-a-macro-to-export-all-instances-of-an-enum-type/73137 "2021-12-15T11:35:02Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@paalon](https://discourse.julialang.org/u/paalon)
#### Post date: [December 15, 2021, 11:35am UTC](https://discourse.julialang.org/t/how-to-write-a-macro-to-export-all-instances-of-an-enum-type/73137/1 "2021-12-15T11:35:02Z")
A module has an enum type `A` and I want to export all its instances `instances(A)`.
I want to write a macro `@export_instances` like
```julia
module MyModule
export A
@enum A a b c
@export_instances A
# `export a, b, c`
end # module
```
I have read [Julia documentation’s metaprogramming page](https://docs.julialang.org/en/v1/manual/metaprogramming/) and [Export enum - #4 by mathieu17g](https://discourse.julialang.org/t/export-enum/5396/4). I was able to implement the following function to return the expression to export all instances of an enum type `T`.
```julia
function export_instances(T)
:(export $(Symbol.(instances(T))...))
end
```
Then, I have tried to write the desired macro but can’t. How do I?
---
### Author:  [@paalon](https://discourse.julialang.org/u/paalon)
#### Post date: [December 20, 2021, 4:31am UTC](https://discourse.julialang.org/t/how-to-write-a-macro-to-export-all-instances-of-an-enum-type/73137/2 "2021-12-20T04:31:36Z")
Alex Arslan taught me on the Julia Slack
```julia
module Thing
macro exportinstances(enum)
eval = GlobalRef(Core, :eval)
return :($eval($ __module__ , Expr(:export, map(Symbol, instances($enum))...)))
end
@enum Fruit apple banana
@enuminstances Fruit
end # module
```
---
### Author:  [@PGS62](https://discourse.julialang.org/u/PGS62)
#### Post date: [September 22, 2022, 8:45am UTC](https://discourse.julialang.org/t/how-to-write-a-macro-to-export-all-instances-of-an-enum-type/73137/3 "2022-09-22T08:45:58Z")
That was very useful, though I think the penultimate line of the solution should read:
```julia
@exportinstances Fruit
```