# Pretty macroexpand in Base?
**URL:** https://discourse.julialang.org/t/pretty-macroexpand-in-base/47132
**Category:** General Usage
**Created:** [September 23, 2020, 12:20pm UTC](https://discourse.julialang.org/t/pretty-macroexpand-in-base/47132 "2020-09-23T12:20:31Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@johnmyleswhite](https://discourse.julialang.org/u/johnmyleswhite)
#### Post date: [September 23, 2020, 12:20pm UTC](https://discourse.julialang.org/t/pretty-macroexpand-in-base/47132/1 "2020-09-23T12:20:31Z")
Whenever I talk to someone about macros, I always suggest they start by looking at the expansion of the macro. But the default expansion isn’t super readable because of LineNumberNode’s, gensyms, etc.
So I almost always end up using MacroTools.prettify:
```julia
MacroTools.prettify(@macroexpand @everywhere x = 1)
```
Should Base Julia have the equivalent of this composition in it? It seems like it could make macros more accessible.
---
### Author:  [@tomerarnon](https://discourse.julialang.org/u/tomerarnon)
#### Post date: [September 23, 2020, 12:25pm UTC](https://discourse.julialang.org/t/pretty-macroexpand-in-base/47132/2 "2020-09-23T12:25:39Z")
Agreed! I’ll just add that I sometimes prefer
```julia
MacroTools.prewalk(rmlines, @macroexpand @everywhere x = 1)
```
to see the original variable names (even if they’re mangled) as this can give a much better idea of what’s going on for larger macros. A way to get the original symbols (unmangled) would be even better…
---
### Author:  [@fredrikekre](https://discourse.julialang.org/u/fredrikekre)
#### Post date: [September 23, 2020, 1:10pm UTC](https://discourse.julialang.org/t/pretty-macroexpand-in-base/47132/3 "2020-09-23T13:10:42Z")
> [@tomerarnon](#):
>
> ` MacroTools.prewalk(rmlines, @macroexpand @everywhere x = 1)`
This looks equivalent to `Base.remove_linenums!` unless I am missing something? It should be pretty trivial to support a kwarg to `@macroexpand` that just remove linenumbers (similar to e.g. `@code_llvm` which has `debuginfo` as a kwarg).
---
### Author:  [@tomerarnon](https://discourse.julialang.org/u/tomerarnon)
#### Post date: [September 23, 2020, 1:16pm UTC](https://discourse.julialang.org/t/pretty-macroexpand-in-base/47132/4 "2020-09-23T13:16:26Z")
Nice, I didn’t know there was already a way to do it in Base!
> [@fredrikekre](#):
>
> support a kwarg to `@macroexpand` that just remove linenumbers
This sounds great. Arguably the “brief” printout is more commonly needed than the verbose one, so maybe `brief=true` should even be the default?
---
### Author:  [@mcabbott](https://discourse.julialang.org/u/mcabbott)
#### Post date: [September 23, 2020, 1:16pm UTC](https://discourse.julialang.org/t/pretty-macroexpand-in-base/47132/5 "2020-09-23T13:16:35Z")
The MacroTools version catches some line-numbers that the Base one misses:
```julia
julia> Base.remove_linenums!(@macroexpand1 @assert 1 == @view A[1])
:(if 1 == #= REPL[57]:1 =# @view(A[1])
nothing
else
Base.throw(Base.AssertionError("1 == #= REPL[57]:1 =# @view(A[1])"))
end)
julia> MacroTools.prewalk(rmlines, @macroexpand1 @assert 1 == @view A[1])
:(if 1 == @view(A[1])
nothing
else
Base.throw(Base.AssertionError("1 == #= REPL[58]:1 =# @view(A[1])"))
end)
```
---
### Author:  [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)
#### Post date: [September 23, 2020, 1:22pm UTC](https://discourse.julialang.org/t/pretty-macroexpand-in-base/47132/6 "2020-09-23T13:22:05Z")
I think that the best solution is to make MacroTools a standard library (ideally after stdlib version numbers are decoupled from Julia proper).
It has a lot of useful functionality, and is practically indispensable for working with macros in Julia.
---
### Author:  [@simeonschaub](https://discourse.julialang.org/u/simeonschaub)
#### Post date: [September 23, 2020, 1:22pm UTC](https://discourse.julialang.org/t/pretty-macroexpand-in-base/47132/7 "2020-09-23T13:22:59Z")
Yes, it doesn’t strip out `LineNumberNode`s from `macrocall` expressions. I think `rmlines` actually replaces those with `nothing`.