# What are the limitations of completion in the REPL?
**URL:** https://discourse.julialang.org/t/what-are-the-limitations-of-completion-in-the-repl/78944
**Category:** General Usage
**Tags:** repl
**Created:** [April 3, 2022, 1:54pm UTC](https://discourse.julialang.org/t/what-are-the-limitations-of-completion-in-the-repl/78944 "2022-04-03T13:54:14Z")
**Posts on this page:** 12
**Page:** 1
### Author:  [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)
#### Post date: [April 3, 2022, 1:54pm UTC](https://discourse.julialang.org/t/what-are-the-limitations-of-completion-in-the-repl/78944/1 "2022-04-03T13:54:14Z")
The manual states “Tab completion can also help completing fields:”, using the example of UUIDs.
However, I recently found that some symbols are not completed ([Where is sparse ldlt? - #2 by skleinbo](https://discourse.julialang.org/t/where-is-sparse-ldlt/78929/2)).
So, does anyone know what are the limitations and how does the completion work (or does not?)?
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### Author:  [@Sukera](https://discourse.julialang.org/u/Sukera)
#### Post date: [April 3, 2022, 2:34pm UTC](https://discourse.julialang.org/t/what-are-the-limitations-of-completion-in-the-repl/78944/2 "2022-04-03T14:34:00Z")
REPL completion works by looking up what symbols are associated with the object in front of the dot. If a symbol is not part of those associated symbols, completion can’t know about it on its own. In your example, SuiteSparse is extending a function from another module, in this case LinearAlgebra, which means the `ldlt` symbol is not associated with the module `SuiteSparse` in the first place, resulting in there not being completion for it.
It’s also not trivial to just make that available anyway, since `ldlt` doesn’t exist from the POV of the `SuiteSparse` module in the first place. Writing `SuiteSparse.ldlt` would have to reference `LinearAlgebra.ldlt`, which seems very confusing to me.
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### Author:  [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)
#### Post date: [April 3, 2022, 3:45pm UTC](https://discourse.julialang.org/t/what-are-the-limitations-of-completion-in-the-repl/78944/3 "2022-04-03T15:45:28Z")
So are you saying that the completion can only look up functions, not methods?
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### Author:  [@Sukera](https://discourse.julialang.org/u/Sukera)
#### Post date: [April 3, 2022, 10:12pm UTC](https://discourse.julialang.org/t/what-are-the-limitations-of-completion-in-the-repl/78944/4 "2022-04-03T22:12:39Z")
No, not exactly. Both the function and the method live in `LinearAlgebra`, the text resulting in the method is just “physically” written in `SuiteSparse`. REPL completion can look up things that actually end up as part of `SuiteSparse`, which the method defined for `ldlt` doesn’t.
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### Author:  [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)
#### Post date: [April 3, 2022, 10:27pm UTC](https://discourse.julialang.org/t/what-are-the-limitations-of-completion-in-the-repl/78944/5 "2022-04-03T22:27:19Z")
How did you come to that conclusion? I can see `ldlt` in [https://github.com/JuliaSparse/SuiteSparse.jl/blob/f31dc2e45c9edd2f9969c336a440c9aca13d6e44/src/cholmod.jl#L1336](https://github.com/JuliaSparse/SuiteSparse.jl/blob/f31dc2e45c9edd2f9969c336a440c9aca13d6e44/src/cholmod.jl#L1336)
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### Author:  [@Sukera](https://discourse.julialang.org/u/Sukera)
#### Post date: [April 3, 2022, 10:40pm UTC](https://discourse.julialang.org/t/what-are-the-limitations-of-completion-in-the-repl/78944/6 "2022-04-03T22:40:32Z")
> [@PetrKryslUCSD](#):
>
> How did you come to that conclusion?
It’s imported here:
>
which means that the `ldlt` you link extends that function with a new method instead of creating an entirely different function.
You can also run `SuiteSparse.ldlt === LinearAlgebra.ldlt` to check that they’re the same.
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### Author:  [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)
#### Post date: [April 3, 2022, 10:42pm UTC](https://discourse.julialang.org/t/what-are-the-limitations-of-completion-in-the-repl/78944/7 "2022-04-03T22:42:24Z")
Right, but still, the method is defined in CHOLMOD. Is that not visible to the completion mechanism?
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### Author:  [@Sukera](https://discourse.julialang.org/u/Sukera)
#### Post date: [April 3, 2022, 10:47pm UTC](https://discourse.julialang.org/t/what-are-the-limitations-of-completion-in-the-repl/78944/8 "2022-04-03T22:47:19Z")
No, REPL completion doesn’t know (or care) where things are written in a file, only whether they’re part of the resulting module or not. Files in general are not nearly as important in julia as in other languages like python - they’re not coupled to the module structure or what’s reachable from them in code per se.
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### Author:  [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)
#### Post date: [April 3, 2022, 10:59pm UTC](https://discourse.julialang.org/t/what-are-the-limitations-of-completion-in-the-repl/78944/9 "2022-04-03T22:59:51Z")
I understand that (I think), but the method is defined in a module. Shouldn’t it be visible in the module then?
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### Author:  [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)
#### Post date: [April 4, 2022, 3:07am UTC](https://discourse.julialang.org/t/what-are-the-limitations-of-completion-in-the-repl/78944/10 "2022-04-04T03:07:27Z")
Okay, here is an example:
```julia
julia> include("m1.jl")
Main.m1
julia> include("m2.jl")
Main.m2
julia> Main.m2.
eval f include
julia> Main.m2.f
f (generic function with 2 methods)
julia> Main.m1.
eval f include
julia> Main.m1.f
f (generic function with 2 methods)
shell> cat m1.jl m2.jl
module m1
export f
function f(x::Float64)
x*4
end
end
module m2
import ..m1: f
export f
function f(x::Int64)
f(Float64(x))
end
end
```
As you can see, completion suggests function methods for `f` from both module `m1` and module `m2`, even though `m2` only defines a method for `f`. Isn’t that the same situation as for `ldlt`?
Edit: With a submodule.
```julia
julia> include("m3.jl")
WARNING: replacing module m3.
Main.m3
julia> Main.m3.
eval include subm3
julia> Main.m3.subm3.
eval f include
julia> Main.m3.subm3.f
f (generic function with 2 methods)
shell> cat m3.jl
module m3
module subm3
import ...m1: f
export f
function f(x::Int64)
f(Float64(x))
end
end
end
```
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### Author:  [@Sukera](https://discourse.julialang.org/u/Sukera)
#### Post date: [April 4, 2022, 6:10am UTC](https://discourse.julialang.org/t/what-are-the-limitations-of-completion-in-the-repl/78944/11 "2022-04-04T06:10:57Z")
> [@PetrKryslUCSD](#):
>
> Shouldn’t it be visible in the module then?
This is where the distinction between “where it’s written” and “where it’s associated with/where the method belongs” lies. It’s _written_ in that file, yes, but that doesn’t necessarily mean that it semantically belongs to that module. It’s similar to when you do
```julia
module B
# empty module
end
# Here B.C doesn't work
module A
using ..B
@eval B const C = 1
end
# After this, B.C works
```
You wouldn’t expect `A.C` to work, right? The same goes for `ldlt` of `SuiteSparse`.
> [@PetrKryslUCSD](#):
>
> As you can see, completion suggests function methods for `f` from both module `m1` and module `m2` , even though `m2` only defines a method for `f` . Isn’t that the same situation as for `ldlt` ?
No, because in you’re example you’re reexporting `f` from `m2`, which associates the name with `m2` as well (and `m1` of course already has `f` associated with it). This is not the case for `SuiteSparse` - the method is not reexported (the reason for which is possibly due to the method [only being added conditionally](https://github.com/JuliaSparse/SuiteSparse.jl/blob/f31dc2e45c9edd2f9969c336a440c9aca13d6e44/src/SuiteSparse.jl#L27-L31)).
The same goes for your `submodule` example. The submodule `subm3` reexports `f` (which happens independently of being placed in `m3`) and thus has the name available, while `m3` itself does not. It doesn’t know about any `f` (function or methods) at all - it only knows about the name `subm3`.
---
### Author:  [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)
#### Post date: [April 4, 2022, 1:31pm UTC](https://discourse.julialang.org/t/what-are-the-limitations-of-completion-in-the-repl/78944/12 "2022-04-04T13:31:31Z")
Of course, the `export` is the key. You are right.