# Why is Base.OneTo not exported?

**URL:** <https://discourse.julialang.org/t/why-is-base-oneto-not-exported/56976>\
**Category:** New to Julia\
**Tags:** question\
**Created:** [March 11, 2021, 9:36pm UTC](https://discourse.julialang.org/t/why-is-base-oneto-not-exported/56976 "2021-03-11T21:36:36Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![nsajko](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nsajko/32/221187_2.png) [@nsajko](https://discourse.julialang.org/u/nsajko)\
**Post date:** [March 11, 2021, 9:36pm UTC](https://discourse.julialang.org/t/why-is-base-oneto-not-exported/56976/1 "2021-03-11T21:36:36Z")

</div>

It’s quite weird (and somewhat worrying) how I can’t refer to `Base.OneTo` as just `OneTo`:

```julia
$ julia
               _
   _ _ _(_)_ | Documentation: https://docs.julialang.org
  (_) | (_) (_) |
   _ _ _| |_ __ _ | Type "?" for help, "]?" for Pkg help.
  | | | | | | |/ _` | |
  | | |_| | | | (_| | | Version 1.5.3 (2020-11-09)
 _/ |\ __'_|_|_|\__'_| |
|__/ |

julia> OneTo
ERROR: UndefVarError: OneTo not defined
Stacktrace:
 [1] top-level scope
 [2] run_repl(::REPL.AbstractREPL, ::Any) at /build/julia/src/julia-1.5.3/usr/share/julia/stdlib/v1.5/REPL/src/REPL.jl:288

julia> Base.OneTo
Base.OneTo

julia> StepRangeLen # Another Base resident
StepRangeLen

julia> using Base

julia> OneTo
ERROR: UndefVarError: OneTo not defined
Stacktrace:
 [1] top-level scope
 [2] run_repl(::REPL.AbstractREPL, ::Any) at /build/julia/src/julia-1.5.3/usr/share/julia/stdlib/v1.5/REPL/src/REPL.jl:288

```

Is this for backwards compatibility with user programs that may have used the name `OneTo` in older programs? Is `Base.OneTo` experimental? The documentation does not give me that impression.

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**Author:** ![Mason](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mason/32/2423_2.png) [@Mason](https://discourse.julialang.org/u/Mason)\
**Post date:** [March 11, 2021, 9:42pm UTC](https://discourse.julialang.org/t/why-is-base-oneto-not-exported/56976/2 "2021-03-11T21:42:05Z")

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There’s very little reason for it to be exported. the vast majority of the time you’re fine with `1:n` rather than `OneTo(n)`. If you ever find yourself needing `OneTo`, you can just do

```julia
using Base: OneTo

```

`Base.OneTo` is not new or experimental.

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<div class="post-metadata">

**Author:** ![nsajko](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nsajko/32/221187_2.png) [@nsajko](https://discourse.julialang.org/u/nsajko)\
**Post date:** [March 11, 2021, 9:43pm UTC](https://discourse.julialang.org/t/why-is-base-oneto-not-exported/56976/3 "2021-03-11T21:43:38Z")

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Are there other such features that are meant for the public and documented, but not exported?

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<div class="post-metadata">

**Author:** ![mkitti](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mkitti/32/12459_2.png) [@mkitti](https://discourse.julialang.org/u/mkitti)\
**Post date:** [March 11, 2021, 11:13pm UTC](https://discourse.julialang.org/t/why-is-base-oneto-not-exported/56976/4 "2021-03-11T23:13:23Z")

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I recently proposed exporting it’s lowercase cousin `oneto`. You may be interested in the discussion in that closed PR:  
[https://github.com/JuliaLang/julia/pull/39242](https://github.com/JuliaLang/julia/pull/39242)

A related PR is returning `Base.OneTo` from `range(; stop)` or `range(; length)` where `stop` or `length` are given as the only keyword argument:  
[https://github.com/JuliaLang/julia/pull/39241](https://github.com/JuliaLang/julia/pull/39241)

A more controversial idea is to implement `range(stop::Integer) = Base.OneTo(stop)` where a single positional argument is interpreted as `stop`. This would be analogous to `range(stop)` in Python except that it would start with `1` and include `stop`, which is to be expected due to 1-based indexing.

The main argument against making `Base.OneTo` accessible is that you can get almost the same result and performance from a standard `UnitRange` (e.g. `1:5`) as @Mason pointed out and is analyzed in depth in #39242 . The one positional argument form also seems inconsistent with other positional argument forms of `range`.

That said I think the single keyword forms of `range` present a reasonable solution that is unambiguous and exposes an efficient code path in a natural way to users.

---

<div class="post-metadata">

**Author:** ![mkitti](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mkitti/32/12459_2.png) [@mkitti](https://discourse.julialang.org/u/mkitti)\
**Post date:** [March 11, 2021, 11:37pm UTC](https://discourse.julialang.org/t/why-is-base-oneto-not-exported/56976/5 "2021-03-11T23:37:24Z")

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To actually answer this question about whether there are documented unexported symbols in `Base`, here is some code:

```julia
julia> unexported_symbols_in_base = setdiff(names(Base, all = true), names(Base))

julia> meta = Base.Docs.meta(Base);

julia> hasdoc(s) = haskey(meta, Base.Docs.Binding(Base,s))
hasdoc (generic function with 1 method)

julia> filter(hasdoc,unexported_symbols_in_base)
135-element Array{Symbol,1}:
 Symbol("@irrational")
 Symbol("@kwdef")
 Symbol("@locals")
 Symbol("@propagate_inbounds")
 Symbol("@pure")
 :AbstractLock
 :AlwaysLockedST
 :AsyncCollector
 :AsyncCondition
 :AsyncGenerator
 :BottomRF
 :CFunction
 :CodeUnits
 :CyclePadding
 :EnvDict
 :Event
 :FilteringRF
 :Fix1
 :Fix2
 :FlatteningRF
 :Generator
 :GenericCondition
 :IdentityUnitRange
 :ImmutableDict
 :IteratorEltype
 :IteratorSize
 :LogicalIndex
 :MappingRF
 :OneTo
...

```