# Pass variable value to macro inside a for loop
**URL:** https://discourse.julialang.org/t/pass-variable-value-to-macro-inside-a-for-loop/2879
**Category:** General Usage
**Created:** [March 26, 2017, 12:40am UTC](https://discourse.julialang.org/t/pass-variable-value-to-macro-inside-a-for-loop/2879 "2017-03-26T00:40:37Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@djsegal](https://discourse.julialang.org/u/djsegal)
#### Post date: [March 26, 2017, 12:40am UTC](https://discourse.julialang.org/t/pass-variable-value-to-macro-inside-a-for-loop/2879/1 "2017-03-26T00:40:37Z")
I’m trying to get the following lines of code to work, but @export\_all\_files keeps getting a symbol with:
- the value `loaded_folder`
- instead of the folder it should be loaded (i.e. `src` or `config/initializers`)
Why is that happening?
* * *
```julia
loaded_folders = ["src", "config/initializers"]
for loaded_folder in loaded_folders
loaded_folder = "$(pwd())/$loaded_folder"
Julz.include_all_files(loaded_folder)
Julz.@export_all_files loaded_folder
end
```
yields the error
```julia
ERROR: LoadError: UndefVarError: loaded_folder not defined
```
---
### Author:  [@yuyichao](https://discourse.julialang.org/u/yuyichao)
#### Post date: [March 26, 2017, 12:51am UTC](https://discourse.julialang.org/t/pass-variable-value-to-macro-inside-a-for-loop/2879/2 "2017-03-26T00:51:54Z")
Macro expansion happens at parse time so no it’s impossible to get the value of `loaded_folder` in the macro. You can either use a function, or expand to a piece of code that uses it at runtime (possibly by calling functions), or use `eval` to splice in the value and expand the macro at runtime.
---
### Author:  [@djsegal](https://discourse.julialang.org/u/djsegal)
#### Post date: [March 26, 2017, 1:04am UTC](https://discourse.julialang.org/t/pass-variable-value-to-macro-inside-a-for-loop/2879/3 "2017-03-26T01:04:22Z")
> [@yuyichao](#):
>
> use eval to splice in the value and expand the macro at runtime
What do you mean by this?
That seems like the most matter-of-fact answer
---
### Author:  [@yuyichao](https://discourse.julialang.org/u/yuyichao)
#### Post date: [March 26, 2017, 1:19am UTC](https://discourse.julialang.org/t/pass-variable-value-to-macro-inside-a-for-loop/2879/4 "2017-03-26T01:19:11Z")
`@eval Julz.@export_all_files $loaded_folder` or `eval(:(Julz.@export_all_files $loaded_folder))`. Obviously only works in global scope.