# What are everyone's style for documenting types (used for containers or for dispatch-only/"traits")?

**URL:** <https://discourse.julialang.org/t/what-are-everyones-style-for-documenting-types-used-for-containers-or-for-dispatch-only-traits/101991>\
**Category:** Internals & Design\
**Tags:** documentation\
**Created:** [July 23, 2023, 10:57pm UTC](https://discourse.julialang.org/t/what-are-everyones-style-for-documenting-types-used-for-containers-or-for-dispatch-only-traits/101991 "2023-07-23T22:57:54Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![RoyW](https://avatars.discourse-cdn.com/v4/letter/r/e9bcb4/32.png) [@RoyW](https://discourse.julialang.org/u/RoyW)\
**Post date:** [July 23, 2023, 10:57pm UTC](https://discourse.julialang.org/t/what-are-everyones-style-for-documenting-types-used-for-containers-or-for-dispatch-only-traits/101991/1 "2023-07-23T22:57:54Z")

</div>

I’m trying to document my Julia packages not necessarily to the style of Base, but so that it communicates the ideas fast to serious users who have a basic training with Julia but have prior programming or even software development experience. Please let me know below how you’d document the following:

Suppose you have a Holy-trait, which I understand is a data type that triggers different types of dispatch

```julia
abstract type ConstraintType end
struct NoConstraints <: ConstraintType end
struct AffineConstraints <: ConstraintType end
struct BoxConstraints <: end

function runsolver(c::ConstraintType, other_stuff...)

    runspecializedsolver(c, other_stuff...)
end

function runspecializedsolver(c::BoxConstraints, other_stuff...)
    # code.
end

function runspecializedsolver(c::NoConstraints, other_stuff...)
    # code.
end

```

I used to not include the types here in the public API when I use Documenter.jl to build the docs. However, in cases like this one, the user of this package might actually need to know what `ConstraintType ` is, because it is mentioned in the documentation of `runsolver()`s public API. In this case, I’d like to at least explain that `ConstraintType ` is a supertype of `BoxConstraints`, and one should really call `BoxConstraints` or `AffineConstraints` in their code before they call `runsolver()`.

I’ve resorted to just doing

```julia
"""
abstract type ConstraintType end
"""
abstract type ConstraintType end

# etc.

```

for all the types, which is quite a bit of boiler plate documentation code. I understand Julia users can always just do `?ConstraintType` in the Julia REPL and get equivalent auto-generated like the ones I’m using, but this would not make it to the public API page generated by Documenter.jl.

I’m interested in hearing what others here would do.