NEWS.md

Julia v1.6 Release Notes

New language features

• Types written with where syntax can now be used to define constructors, e.g. (Foo{T} where T)(x) = ....
• <-- and <--> are now available as infix operators, with the same precedence and associativity as other arrow-like operators ([#36666]).

Language changes

Compiler/Runtime improvements

• All platforms can now use @executable_path within jl_load_dynamic_library(). This allows executable-relative paths to be embedded within executables on all platforms, not just MacOS, which the syntax is borrowed from. ([#35627])
• Constant propogation now occurs through keyword arguments ([#35976])
• The precompilation cache is now created atomically ([#36416]). Invoking n Julia processes simultaneously may create n temporary caches.

Command-line option changes

• There is no longer a concept of "home project": starting julia --project=dir is now exactly equivalent to starting julia and then doing pkg> activate $dir and julia --project is exactly equivalent to doing that where dir = Base.current_project(). In particular, this means that if you do pkg> activate after starting julia with the --project option (or with JULIA_PROJECT set) it will take you to the default active project, which is @v1.5 unless you have modified LOAD_PATH. ([#36434])

Multi-threading changes

Build system changes

• Windows Installer now has the option to 'Add Julia to Path'. To unselect this option from the commandline simply remove the tasks you do not want to be installed: e.g. ./julia-installer.exe /TASKS="desktopicon,startmenu,addtopath", adds a desktop icon, a startmenu group icon, and adds Julia to system PATH.

New library functions

• New function Base.kron! and corresponding overloads for various matrix types for performing Kronecker product in-place. ([#31069]).
• New function Base.Threads.foreach(f, channel::Channel) for multithreaded Channel consumption. ([#34543]).
• New function Base.readeach(io, T) for iteratively performing read(io, T). ([#36150])
• Iterators.map is added. It provides another syntax Iterators.map(f, iterators...) for writing (f(args...) for args in zip(iterators...)), i.e. a lazy map ([#34352]).
• New function sincospi for simultaneously computing sinpi(x) and cospi(x) more efficiently ([#35816]).

New library features

• The redirect_* functions can now be called on IOContext objects.

Standard library changes

• The nextprod function now accepts tuples and other array types for its first argument ([#35791]).
• The function isapprox(x,y) now accepts the norm keyword argument also for numeric (i.e., non-array) arguments x and y ([#35883]).
• view, @view, and @views now work on AbstractStrings, returning a SubString when appropriate ([#35879]).
• All AbstractUnitRange{<:Integer}s now work with SubString, view, @view and @views on strings ([#35879]).
• sum, prod, maximum, and minimum now support init keyword argument ([#36188], [#35839]).
• unique(f, itr; seen=Set{T}()) now allows you to declare the container type used for keeping track of values returned by f on elements of itr ([#36280]).
• Libdl has been moved to Base.Libc.Libdl, however it is still accessible as an stdlib ([#35628]).
• first and last functions now accept an integer as second argument to get that many leading or trailing elements of any iterable ([#34868]).
• intersect on CartesianIndices now returns CartesianIndices instead of Vector{<:CartesianIndex} ([#36643]).

LinearAlgebra

• New method LinearAlgebra.issuccess(::CholeskyPivoted) for checking whether pivoted Cholesky factorization was successful ([#36002]).
• UniformScaling can now be indexed into using ranges to return dense matrices and vectors ([#24359]).
• New function LinearAlgebra.BLAS.get_num_threads() for getting the number of BLAS threads. ([#36360])
• (+)(::UniformScaling) is now defined, making +I a valid unary operation. ([#36784])

Markdown

Random

REPL

• The AbstractMenu extension interface of REPL.TerminalMenus has been extensively overhauled. The new interface does not rely on global configuration variables, is more consistent in delegating printing of the navigation/selection markers, and provides improved support for dynamic menus. These changes are compatible with the previous (deprecated) interface, so are non-breaking.

  The new API offers several enhancements:

  • Menus are configured in their constructors via keyword arguments
  • For custom menu types, the new Config and MultiSelectConfig replace the global CONFIG Dict
  • request(menu; cursor=1) allows you to control the initial cursor position in the menu (defaults to first item)
  • MultiSelectMenu allows you to pass a list of initially-selected items with the selected keyword argument
  • writeLine was deprecated to writeline, and writeline methods are not expected to print the cursor indicator. The old writeLine continues to work, and any of its method extensions should print the cursor indicator as before.
  • printMenu has been deprecated to printmenu, and it both accepts a state input and returns a state output that controls the number of terminal lines erased when the menu is next refreshed. This plus related changes makes printmenu work properly when the number of menu items might change depending on user choices.
  • numoptions, returning the number of items in the menu, has been added as an alternative to implementing options
  • suppress_output (primarily a testing option) has been added as a keyword argument to request, rather than a configuration option

• Windows REPL now supports 24-bit colors, by correctly interpreting virtual terminal escapes.

SparseArrays

• Display large sparse matrices with a Unicode "spy" plot of their nonzero patterns, and display small sparse matrices by an Matrix-like 2d layout of their contents.

Dates

• Quarter period is defined ([#35519]).

Statistics

Sockets

Distributed

UUIDs

• Change uuid1 and uuid4 to use Random.RandomDevice() as default random number generator ([#35872]).
• Added parse(::Type{UUID}, ::AbstractString) method

Deprecated or removed

External dependencies

Tooling Improvements