# No documentation for DataType
**URL:** https://discourse.julialang.org/t/no-documentation-for-datatype/17497
**Category:** General Usage
**Created:** [November 14, 2018, 12:47am UTC](https://discourse.julialang.org/t/no-documentation-for-datatype/17497 "2018-11-14T00:47:37Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@peters](https://discourse.julialang.org/u/peters)
#### Post date: [November 14, 2018, 12:47am UTC](https://discourse.julialang.org/t/no-documentation-for-datatype/17497/1 "2018-11-14T00:47:37Z")
Surprisingly, I found there is no documentation for DataType. Considering its importance (the supertype of most types), don’t you think it deserves to have some description?
-------------------------- Julia ver.1.0.2
help?\> DataType
search: DataType
No documentation found.
Summary
≡≡≡≡≡≡≡≡≡
mutable struct DataType \<: Type{T}
…
---
### Author:  [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)
#### Post date: [November 14, 2018, 7:32am UTC](https://discourse.julialang.org/t/no-documentation-for-datatype/17497/2 "2018-11-14T07:32:54Z")
> [@peters](#):
>
> I found there is no documentation for DataType.
There is, you just didn’t find it. [Reflection and introspection · The Julia Language](https://docs.julialang.org/en/v1/devdocs/reflection/#Reflection-and-introspection-1) documents the layout and fields, which is probably all you need to know, unless you are working on Julia’s internals.
> [@peters](#):
>
> don’t you think it deserves to have some description?
The manual talks about it rather early: [Types · The Julia Language](https://docs.julialang.org/en/v1/manual/types/#Declared-Types-1)
Please don’t assume that all the documentation is in docstrings. A lot of it is, but conceptual issues that transcend particular types or methods are easier to document in the manual.
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### Author:  [@peters](https://discourse.julialang.org/u/peters)
#### Post date: [November 15, 2018, 4:58am UTC](https://discourse.julialang.org/t/no-documentation-for-datatype/17497/3 "2018-11-15T04:58:44Z")
@Tamas_Papp. I read the document and it was helpful. Thanks.
One nice feature of Julia is you can learn the language quickly using RERL so I still think even a brief docstring for DataType can be useful. For instance, I can see UnionAll has the following one so why not for DataType?
UnionAll
A union of types over all values of a type parameter. UnionAll is used
to describe parametric types where the values of some parameters are
not known.
---
### Author:  [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)
#### Post date: [November 15, 2018, 8:34am UTC](https://discourse.julialang.org/t/no-documentation-for-datatype/17497/4 "2018-11-15T08:34:10Z")
> [@peters](#):
>
> even a brief docstring for DataType can be useful
Certainly — I was merely pointing out the documentation. Perhaps you could make a [make a PR](https://github.com/JuliaLang/julia/blob/master/CONTRIBUTING.md#modifying-an-existing-docstring-in-base).