Skip to content

Convenience functions for vals #23658

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
bramtayl wants to merge 6 commits into from
Closed

Convenience functions for vals #23658

Changes from 1 commit
Commits
Show all changes
6 commits
Select commit Hold shift + click to select a range
b97506e
Convenience functions for vals
bramtayl Sep 10, 2017
f92e7cc
Added tests
bramtayl Sep 11, 2017
51d7a1d
Undid tests for wrong PR [ci-skip]
bramtayl Sep 11, 2017
fa2e6ee
Addressed comments
bramtayl Sep 11, 2017
ce19d8f
Added tests
bramtayl Sep 11, 2017
d5d1b58
Update operators.jl
bramtayl Sep 11, 2017
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
14 changes: 14 additions & 0 deletions base/essentials.jl
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -601,6 +601,20 @@ end

Val(x) = (@_pure_meta; Val{x}())

eltype(::Val{T}) where T = T
Copy link
Copy Markdown
Member

@ararslan ararslan Sep 10, 2017

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This isn't correct. T can be Array{S,N}, in which case eltype(Val{Array{S,N}}) should be S. I'd instead make this eltype(::Val{T}) where {T} = eltype(T).

Copy link
Copy Markdown
Contributor Author

@bramtayl bramtayl Sep 10, 2017

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Hmm maybe eltype isn't the right name for what I want. I just want a function that will turn Val{:a}() into :a

Copy link
Copy Markdown
Contributor

@GregPlowman GregPlowman Sep 11, 2017

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

However, might be consistent with this:

Julia-0.7.0-DEV> x = Vector{Array{Int,3}}()
0-element Array{Array{Int64,3},1}

Julia-0.7.0-DEV> eltype(x)
Array{Int64,3}

Copy link
Copy Markdown
Member

@JeffBezanson JeffBezanson Sep 11, 2017

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Val isn't a collection or the type of a collection so eltype is not appropriate here.

Copy link
Copy Markdown
Contributor Author

@bramtayl bramtayl Sep 11, 2017

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I mean I could just leave it out this PR, or choose another name? devalue?


(&)(v1::Val{true}, v2::Val{true}) = Val{true}()
(&)(v1::Val, v2::Val) = Val{false}()
Copy link
Copy Markdown
Contributor

@TotalVerb TotalVerb Sep 10, 2017

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

these methods seem to cover too many possibilities; I'd suggest to just write out all four combinations


(|)(v1::Val{false}, v2::Val{false}) = Val{false}()
(|)(v1::Val, v2::Val) = Val{true}()

!(::Val{false}) = Val{true}()
!(::Val{true}) = Val{false}()

ifelse(switch::Val{false}, new, old) = old
ifelse(switch::Val{true}, new, old) = new

# used by interpolating quote and some other things in the front end
function vector_any(@nospecialize xs...)
n = length(xs)
Expand Down
⚡