Skip to content

Latest commit

 

History

History
1376 lines (1054 loc) · 71 KB

NEWS.md

File metadata and controls

1376 lines (1054 loc) · 71 KB
Raw

Julia v0.7.0 Release Notes

New language features

  • Local variables can be tested for being defined using the new @isdefined variable macro (#22281).

  • Destructuring in function arguments: when an expression such as (x, y) is used as a function argument name, the argument is unpacked into local variables x and y as in the assignment (x, y) = arg ([#6614]).

  • Custom infix operators can now be defined by appending Unicode combining marks, primes, and sub/superscripts to other operators. For example, +̂ₐ″ is parsed as an infix operator with the same precedence as + ([#22089]).

Language changes

  • The syntax for parametric methods, function f{T}(x::T), has been changed to function f(x::T) where {T} (#11310).

  • The syntax 1.+2 is deprecated, since it is ambiguous: it could mean either 1 .+ 2 (the current meaning) or 1. + 2 (#19089).

  • In string and character literals, backslash \ may no longer precede unrecognized escape characters (#22800).

  • Juxtaposing binary, octal, and hexadecimal literals is deprecated, since it can lead to confusing code such as 0xapi == 0xa * pi ([#16356]).

  • Declaring arguments as x::ANY to avoid specialization has been replaced by @nospecialize x. (#22666).

  • Keyword argument default values are now evaluated in successive scopes --- the scope for each expression includes only previous keyword arguments, in left-to-right order (#17240).

  • The parsing of 1<<2*3 as 1<<(2*3) is deprecated, and will change to (1<<2)*3 in a future version (#13079).

  • { } expressions now use braces and bracescat as expression heads instead of cell1d and cell2d, and parse similarly to vect and vcat (#8470).

  • Nested if expressions that arise from the keyword elseif now use elseif as their expression head instead of if (#21774).

  • let blocks now parse the same as for loops; the first argument is either an assignment or block of assignments, and the second argument is a block of statements (#21774).

  • Parsed and lowered forms of type definitions have been synchronized with their new keywords (#23157). Expression heads are renamed as follows:

    • type => struct

    • bitstype => primitive (order of arguments is also reversed, to match syntax)

    • composite_type => struct_type

    • bits_type => primitive_type

  • The global keyword now only introduces a new binding if one doesn't already exist in the module. This means that assignment to a global (global sin = 3) may now throw the error: "cannot assign variable Base.sin from module Main", rather than emitting a warning. Additionally, the new bindings are now created before the statement is executed. For example, f() = (global sin = "gluttony"; nothing) will now resolve which module contains sin eagerly, rather than delaying that decision until f is run. (#22984).

  • Dispatch rules have been simplified: method matching is now determined exclusively by subtyping; the rule that method type parameters must also be captured has been removed. Instead, attempting to access the unconstrained parameters will throw an UndefVarError. Linting in package tests is recommended to confirm that the set of methods which might throw UndefVarError when accessing the static parameters (need_to_handle_undef_sparam = Set{Any}(m.sig for m in Test.detect_unbound_args(Base, recursive=true))) is equal (==) to some known set (expected = Set()). (#23117)

  • const declarations on local variables were previously ignored. They now give a warning, so that this syntax can be disallowed or given a new meaning in a future version ([#5148]).

  • Placing an expression after catch, as in catch f(x), is deprecated. Use catch; f(x) instead ([#19987]).

  • In for i = ..., if a local variable i already existed it would be overwritten during the loop. This behavior is deprecated, and in the future for loop variables will always be new variables local to the loop ([#22314]). The old behavior of overwriting an existing variable is available via for outer i = ....

  • In for i in x, x used to be evaluated in a new scope enclosing the for loop. Now it is evaluated in the scope outside the for loop.

  • Variable bindings local to while loop bodies are now freshly allocated on each loop iteration, matching the behavior of for loops.

  • Prefix & for by-reference arguments to ccall has been deprecated in favor of Ref argument types ([#6080]).

  • All line numbers in ASTs are represented by LineNumberNodes; the :line expression head is no longer used. QuoteNodes are also consistently used for quoted symbols instead of the :quote expression head (though :quote Exprs are still used for quoted expressions) ([#23885]).

Breaking changes

This section lists changes that do not have deprecation warnings.

  • getindex(s::String, r::UnitRange{Int}) now throws UnicodeError if last(r) is not a valid index into s ([#22572]).

  • ntuple(f, n::Integer) throws ArgumentError if n is negative. Previously an empty tuple was returned (#21697).

  • Juxtaposing string literals (e.g. "x"y) is now a syntax error (#20575).

  • Macro calls with for expressions are now parsed as generators inside function argument lists (#18650). Examples:

    • sum(@inbounds a[i] for i = 1:n) used to give a syntax error, but is now parsed as sum(@inbounds(a[i]) for i = 1:n).

    • sum(@m x for i = 1:n end) used to parse the argument to sum as a 2-argument call to macro @m, but now parses it as a generator plus a syntax error for the dangling end.

  • @__DIR__ returns the current working directory rather than nothing when not run from a file (#21759).

  • @__FILE__ and @__DIR__ return information relative to the file that it was parsed from, rather than from the task-local SOURCE_PATH global when it was expanded.

  • All macros receive an extra argument __source__::LineNumberNode which describes the parser location in the source file for the @ of the macro call. It can be accessed as a normal argument variable in the body of the macro. This is implemented by inserting an extra leading argument into the Expr(:macrocall, :@name, LineNumberNode(...), args...) surface syntax. (#21746)

  • Passing the same keyword argument multiple times is now a syntax error (#16937).

  • getsockname on a TCPSocket now returns the locally bound address and port of the socket. Previously the address of the remote endpoint was being returned (#21825).

  • Using ARGS within the ~/.juliarc.jl or within a .jl file loaded with --load will no longer contain the script name as the first argument. Instead the script name will be assigned to PROGRAM_FILE. (#22092)

  • The format for a ClusterManager specifying the cookie on the command line is now --worker=<cookie>. --worker <cookie> will not work as it is now an optional argument.

  • The representation of CartesianRange has changed to a tuple-of-AbstractUnitRanges; the start and stop fields are no longer present. Use first(R) and last(R) to obtain start/stop. (#20974)

  • The Diagonal, Bidiagonal, Tridiagonal and SymTridiagonal type definitions have changed from Diagonal{T}, Bidiagonal{T}, Tridiagonal{T} and SymTridiagonal{T} to Diagonal{T,V<:AbstractVector{T}}, Bidiagonal{T,V<:AbstractVector{T}}, Tridiagonal{T,V<:AbstractVector{T}} and SymTridiagonal{T,V<:AbstractVector{T}} respectively (#22718, #22925, #23035, [#23154]).

  • When called with an argument that contains NaN elements, findmin and findmax now return the first NaN found and its corresponding index. Previously, NaN elements were ignored. The new behavior matches that of min, max, minimum, and maximum.

  • isapprox(x,y) now tests norm(x-y) <= max(atol, rtol*max(norm(x), norm(y))) rather than norm(x-y) <= atol + ..., and rtol defaults to zero if an atol > 0 is specified ([#22742]).

  • Spaces are no longer allowed between @ and the name of a macro in a macro call (#22868).

  • Juxtaposition of a non-literal with a macro call (x@macro) is no longer valid syntax (#22868).

  • On a cluster, all files are now loaded from the local file system rather than node 1 (#22588). To load the same file everywhere from node 1, one possible alternative is to broadcast a call to include_string: @everywhere include_string(Main, $(read("filename", String)), "filename"). Improving upon this API is left as an opportunity for packages.

  • randperm(n) and randcycle(n) now always return a Vector{Int} (independent of the type of n). Use the corresponding mutating functions randperm! and randcycle! to control the array type (#22723).

  • Worker-worker connections are setup lazily for an :all_to_all topology. Use keyword arg lazy=false to force all connections to be setup during a addprocs call. (#22814)

  • In joinpath(a, b) on Windows, if the drive specifications of a and b do not match, joinpath now returns b instead of throwing an ArgumentError. joinpath(path...) is defined to be left associative, so if any argument has a drive path which does not match the drive of the join of the preceding paths, the prior ones are dropped. ([#20912])

  • ^(A::AbstractMatrix{<:Integer}, p::Integer) now throws a DomainError if p < 0, unless A == one(A) or A == -one(A) (same as for ^(A::Integer, p::Integer)) ([#23366]).

  • ^(A::AbstractMatrix{<:Integer}, p::Integer) now promotes the element type in the same way as ^(A::Integer, p::Integer). This means, for instance, that [1 1; 0 1]^big(1) will return a Matrix{BigInt} instead of a Matrix{Int} ([#23366]).

  • The element type of the input is now preserved in unique. Previously the element type of the output was shrunk to fit the union of the type of each element in the input. (#22696)

  • The promote function now raises an error if its arguments are of different types and if attempting to convert them to a common type fails to change any of their types. This avoids stack overflows in the common case of definitions like f(x, y) = f(promote(x, y)...) ([#22801]).

  • findmin, findmax, indmin, and indmax used to always return linear indices. They now return CartesianIndexes for all but 1-d arrays, and in general return the keys of indexed collections (e.g. dictionaries) ([#22907]).

  • The openspecfun library is no longer built and shipped with Julia, as it is no longer used internally (#22390).

  • All loaded packges used to have bindings in Main (e.g. Main.Package). This is no longer the case; now bindings will only exist for packages brought into scope by typing using Package or import Package ([#17997]).

  • slicedim(b::BitVector, 1, x) now consistently returns the same thing that b[x] would, consistent with its documentation. Previously it would return a BitArray{0} for scalar x ([#20233]).

  • The rules for mixed-signedness integer arithmetic (e.g. Int32(1) + UInt64(1)) have been simplified: if the arguments have different sizes (in bits), then the type of the larger argument is used. If the arguments have the same size, the unsigned type is used ([#9292]).

  • All command line arguments passed via -e, -E, and -L will be executed in the order given on the command line ([#23665]).

Library improvements

  • The functions strip, lstrip and rstrip now return SubString (#22496).

  • The functions strwidth and charwidth have been merged into textwidth([#20816]).

  • The functions base and digits digits now accept a negative base (like ndigits did) (#21692).

  • The function randn now accepts complex arguments (Complex{T <: AbstractFloat}) (#21973).

  • The function rand can now pick up random elements from strings, associatives and sets (#22228, #21960, #18155, #22224).

  • Method lists are now printed as a numbered list. In addition, the source code of a method can be opened in an editor by entering the corresponding number in the REPL and pressing ^Q (#22007).

  • getpeername on a TCPSocket returns the address and port of the remote endpoint of the TCP connection (#21825).

  • resize! and sizehint! methods no longer over-reserve memory when the requested array size is more than double of its current size (#22038).

  • The crc32c function for CRC-32c checksums is now exported (#22274).

  • The output of versioninfo is now controlled with keyword arguments (#21974).

  • The function LibGit2.set_remote_url now always sets both the fetch and push URLs for a git repo. Additionally, the argument order was changed to be consistent with the git command line tool (#22062).

  • logspace now accepts a base keyword argument to specify the base of the logarithmic range. The base defaults to 10 (#22310).

  • Added unique! which is an inplace version of unique (#20549).

  • @test isequal(x, y) and @test isapprox(x, y) now prints an evaluated expression when the test fails (#22296).

  • Uses of Val{c} in Base has been replaced with Val{c}(), which is now easily accessible via the @pure constructor Val(c). Functions are defined as f(::Val{c}) = ... and called by f(Val(c)). Notable affected functions include: ntuple, Base.literal_pow, sqrtm, lufact, lufact!, qrfact, qrfact!, cholfact, cholfact!, _broadcast!, reshape, cat and cat_t.

  • A new @macroexpand1 macro for non recursive macro expansion (#21662).

  • Chars can now be concatenated with Strings and/or other Chars using * (#22532).

  • Diagonal, Bidiagonal, Tridiagonal and SymTridiagonal are now parameterized on the type of the wrapped vectors, allowing Diagonal, Bidiagonal, Tridiagonal and SymTridiagonal matrices with arbitrary AbstractVectors (#22718, #22925, #23035, [#23154]).

  • Mutating versions of randperm and randcycle have been added: randperm! and randcycle! (#22723).

  • BigFloat random numbers can now be generated ([#22720]).

  • REPL Undo via Ctrl-/ and Ctrl-_

  • New function equalto(x), which returns a function that compares its argument to x using isequal ([#23812]).

Compiler/Runtime improvements

  • The inlining heuristic now models the approximate runtime cost of a method (using some strongly-simplifying assumptions). Functions are inlined unless their estimated runtime cost substantially exceeds the cost of setting up and issuing a subroutine call. (#22210, #22732)

Deprecated or removed

  • The keyword immutable is fully deprecated to struct, and type is fully deprecated to mutable struct (#19157, #20418).

  • Indexing into multidimensional arrays with more than one index but fewer indices than there are dimensions is no longer permitted when those trailing dimensions have lengths greater than 1. Instead, reshape the array or add trailing indices so the dimensionality and number of indices match ([#14770], [#23628]).

  • writecsv(io, a; opts...) has been deprecated in favor of writedlm(io, a, ','; opts...) ([#23529]).

  • The method srand(rng, filename, n=4) has been deprecated (#21359).

  • readcsv(io[, T::Type]; opts...) has been deprecated in favor of readdlm(io, ','[, T]; opts...) ([#23530]).

  • The cholfact/cholfact! methods that accepted an uplo symbol have been deprecated in favor of using Hermitian (or Symmetric) views (#22187, #22188).

  • isposdef(A::AbstractMatrix, UL::Symbol) and isposdef!(A::AbstractMatrix, UL::Symbol) have been deprecated in favor of isposdef(Hermitian(A, UL)) and isposdef!(Hermitian(A, UL)) respectively (#22245).

  • The bkfact/bkfact! methods that accepted uplo and issymmetric symbols have been deprecated in favor of using Hermitian (or Symmetric) views (#22605).

  • The function current_module is deprecated and replaced with @__MODULE__ (#22064). This caused the deprecation of some reflection methods (such as macroexpand and isconst), which now require a module argument. And it caused the bugfix of other default arguments to use the Main module (including whos, which).

  • The Operators module is deprecated. Instead, import required operators explicitly from Base, e.g. import Base: +, -, *, / (#22251).

  • Bindings to the FFTW library have been removed from Base. The DFT framework for building FFT implementations is now in AbstractFFTs.jl, the bindings to the FFTW library are in FFTW.jl, and the Base signal processing functions which used FFTs are now in DSP.jl (#21956).

  • The corrected positional argument to cov has been deprecated in favor of a keyword argument with the same name (#21709).

  • Omitting spaces around the ? and the : tokens in a ternary expression has been deprecated. Ternaries must now include some amount of whitespace, e.g. x ? a : b rather than x?a:b (#22523 and #22712).

  • ? can no longer be used as an identifier name (#22712)

  • The method replace(s::AbstractString, pat, r, count) with count <= 0 is deprecated in favor of replace(s::AbstractString, pat, r, typemax(Int)) (#22325).

  • read(io, type, dims) is deprecated to read!(io, Array{type}(dims)) (#21450).

  • read(::IO, ::Ref) is now a method of read!, since it mutates its Ref argument (#21592).

  • Bidiagonal constructors now use a Symbol (:U or :L) for the upper/lower argument, instead of a Bool or a Char (#22703).

  • Bidiagonal, Tridiagonal and SymTridiagonal constructors that automatically converted the input vectors to the same type are deprecated in favor of explicit conversion (#22925, #23035, [#23154].

  • Calling nfields on a type to find out how many fields its instances have is deprecated. Use fieldcount instead. Use nfields only to get the number of fields in a specific object (#22350).

  • fieldnames now operates only on types. To get the names of fields in an object, use fieldnames(typeof(x)) (#22350).

  • InexactError, DomainError, and OverflowError now take arguments. InexactError(func::Symbol, type, -3) now prints as "ERROR: InexactError: func(type, -3)", DomainError(val, [msg]) prints as "ERROR: DomainError with val:\nmsg", and OverflowError(msg) prints as "ERROR: OverflowError: msg". (#20005, #22751, #22761)

  • The operating system identification functions: is_linux, is_bsd, is_apple, is_unix, and is_windows, have been deprecated in favor of Sys.islinux, Sys.isbsd, Sys.isapple, Sys.isunix, and Sys.iswindows, respectively (#22182).

  • The forms of read, readstring, and eachline that accepted both a Cmd object and an input stream are deprecated. Use e.g. read(pipeline(stdin, cmd)) instead (#22762).

  • The unexported type AbstractIOBuffer has been renamed to GenericIOBuffer (#17360 #22796).

  • Remaining vectorized methods over SparseVectors, particularly floor, ceil, trunc, round, and most common transcendental functions such as exp, log, and sin variants, have been deprecated in favor of dot-syntax (#22961).

  • The method String(io::IOBuffer) is deprecated to String(take!(copy(io))) (#21438).

  • The function readstring is deprecated in favor of read(io, String) (#22793)

  • The function showall is deprecated. Showing entire values is the default, unless an IOContext specifying :limit=>true is in use (#22847).

  • issubtype has been deprecated in favor of <: (which used to be an alias for issubtype).

  • Calling write on non-isbits arrays is deprecated in favor of explicit loops or serialize (#6466).

  • The default juliarc.jl file on Windows has been removed. Now must explicitly include the full path if you need access to executables or libraries in the JULIA_HOME directory, e.g. joinpath(JULIA_HOME, "7z.exe") for 7z.exe (#21540).

  • sqrtm has been deprecated in favor of sqrt ([#23504]).

  • expm has been deprecated in favor of exp (#23233).

  • logm has been deprecated in favor of log ([#23505]).

  • Calling union with no arguments is deprecated; construct an empty set with an appropriate element type using Set{T}() instead (#23144).

  • Vectorized DateTime, Date, and format methods have been deprecated in favor of dot-syntax (#23207).

  • Base.cpad has been removed; use an appropriate combination of rpad and lpad instead (#23187).

  • ctranspose and ctranspose! have been deprecated in favor of adjoint and adjoint!, respectively ([#23235]).

  • filter and filter! on dictionaries now pass a single key=>value pair to the argument function, instead of two arguments ([#17886]).

  • rol, rol!, ror, and ror! have been deprecated in favor of specialized methods for circshift/circshift! (#23404).

  • Base.SparseArrays.SpDiagIterator has been removed ([#23261]).

  • The tuple-of-types form of cfunction, cfunction(f, returntype, (types...)), has been deprecated in favor of the tuple-type form cfunction(f, returntype, Tuple{types...}) ([#23066]).

  • diagm(A::SparseMatrixCSC) has been deprecated in favor of spdiagm(sparsevec(A)) ([#23341]).

  • diagm(A::BitMatrix) has been deprecated, use diagm(vec(A)) instead ([#23373]).

  • ℯ (written as \mscre<TAB> or \euler<TAB>) is now the only (by default) exported name for Euler's number, and the type has changed from Irrational{:e} to Irrational{:ℯ} ([#23427]).

  • The mathematical constants π, pi, ℯ, e, γ, eulergamma, catalan, φ and golden have been have been moved from Base to a new module; Base.MathConstants. Only π, pi and ℯ are now exported by default from Base ([#23427]).

  • eu (previously an alias for ℯ) has been deprecated in favor of ℯ (or MathConstants.e) ([#23427]).

  • GMP.gmp_version(), GMP.GMP_VERSION, GMP.gmp_bits_per_limb(), and GMP.GMP_BITS_PER_LIBM have been renamed to GMP.version(), GMP.VERSION, GMP.bits_per_libm(), and GMP.BITS_PER_LIBM, respectively. Similarly, MPFR.get_version(), has been renamed to MPFR.version() ([#23323]). Also, LinAlg.LAPACK.laver() has been renamed to LinAlg.LAPACK.version() and now returns a VersionNumber.

  • select, select!, selectperm and selectperm! have been renamed respectively to partialsort, partialsort!, partialsortperm and partialsortperm! ([#23051]).

  • The Range abstract type has been renamed to AbstractRange ([#23570]).

  • map on dictionaries previously operated on key=>value pairs. This behavior is deprecated, and in the future map will operate only on values ([#5794]).

  • Automatically broadcasted + and - for array + scalar, scalar - array, and so-on have been deprecated due to inconsistency with linear algebra. Use .+ and .- for these operations instead.

  • isleaftype is deprecated in favor of a simpler predicate isconcrete. Concrete types are those that might equal typeof(x) for some x; isleaftype includes some types for which this is not true. If you are certain you need the old behavior, it is temporarily available as Base._isleaftype ([#17086]).

  • contains(eq, itr, item) is deprecated in favor of any with a predicate ([#23716]).

  • Constructors for LibGit2.UserPasswordCredentials and LibGit2.SSHCredentials which take a prompt_if_incorrect argument are deprecated. Instead, prompting behavior is controlled using the allow_prompt keyword in the LibGit2.CredentialPayload constructor ([#23690]).

  • gradient is deprecated and will be removed in the next release ([#23816]).

  • The timing functions tic, toc, and toq are deprecated in favor of @time and @elapsed ([#17046]).

  • Methods of findfirst, findnext, findlast, and findprev that accept a value to search for are deprecated in favor of passing a predicate ([#19186], [#10593]).

  • find functions now operate only on booleans by default. To look for non-zeros, use x->x!=0 or !iszero ([#23120]).

Command-line option changes

  • New option --warn-overwrite={yes|no} to control the warning for overwriting method definitions. The default is no ([#23002]).

  • New option --banner={yes,no} allows suppressing or forcing the printing of the startup banner, overriding the default behavior (banner in REPL, no banner otherwise). The --quiet option implies --banner=no even in REPL mode but can be overridden by passing --quiet together with --banner=yes (#23342).

  • The option --precompiled has been renamed to --sysimage-native-code ([#23054]).

  • The option --compilecache has been renamed to --compiled-modules ([#23054]).

Julia v0.6.0 Release Notes

New language features

  • New type system capabilities (#8974, #18457)

    • Type parameter constraints can refer to previous parameters, e.g. type Foo{R<:Real, A<:AbstractArray{R}}. Can also be used in method definitions.

    • New syntax Array{T} where T<:Integer, indicating a union of types over all specified values of T (represented by a UnionAll type). This provides behavior similar to parametric methods or typealias, but can be used anywhere a type is accepted. This syntax can also be used in method definitions, e.g. function inv(M::Matrix{T}) where T<:AbstractFloat. Anonymous functions can have type parameters via the syntax ((x::Array{T}) where T<:Real) -> 2x.

    • Implicit type parameters, e.g. Vector{<:Real} is equivalent to Vector{T} where T<:Real, and similarly for Vector{>:Int} (#20414).

    • Much more accurate subtype and type intersection algorithms. Method sorting and identification of equivalent and ambiguous methods are improved as a result.

Language changes

  • "Inner constructor" syntax for parametric types is deprecated. For example, in this definition:

    type Foo{T,S<:Real}
    x
    Foo(x) = new(x)
end

    the syntax Foo(x) = new(x) actually defined a constructor for Foo{T,S}, i.e. the case where the type parameters are specified. For clarity, this definition now must be written as Foo{T,S}(x) where {T,S<:Real} = new(x) (#11310, #20308).

  • The keywords used to define types have changed (#19157, #20418).

    • immutable changes to struct

    • type changes to mutable struct

    • abstract changes to abstract type ... end

    • bitstype 32 Char changes to primitive type Char 32 end

    In 0.6, immutable and type are still allowed as synonyms without a deprecation warning.

  • Multi-line and single-line nonstandard command literals have been added. A nonstandard command literal is like a nonstandard string literal, but the syntax uses backquotes (`) instead of double quotes, and the resulting macro called is suffixed with _cmd. For instance, the syntax q`xyz` is equivalent to @q_cmd "xyz" (#18644).

  • Nonstandard string and command literals can now be qualified with their module. For instance, Base.r"x" is now parsed as Base.@r_str "x". Previously, this syntax parsed as an implicit multiplication (#18690).

  • For every binary operator ⨳, a .⨳ b is now automatically equivalent to the broadcast call (⨳).(a, b). Hence, one no longer defines methods for .* etcetera. This also means that "dot operations" automatically fuse into a single loop, along with other dot calls f.(x) (#17623). Similarly for unary operators (#20249).

  • Newly defined methods are no longer callable from the same dynamic runtime scope they were defined in (#17057).

  • isa is now parsed as an infix operator with the same precedence as in (#19677).

  • @. is now parsed as @__dot__, and can be used to add dots to every function call, operator, and assignment in an expression (#20321).

  • The identifier _ can be assigned, but accessing its value is deprecated, allowing this syntax to be used in the future for discarding values (#9343, #18251, #20328).

  • The typealias keyword is deprecated, and should be replaced with Vector{T} = Array{T,1} or a const assignment (#20500).

  • Experimental feature: x^n for integer literals n (e.g. x^3 or x^-3) is now lowered to Base.literal_pow(^, x, Val{n}), to enable compile-time specialization for literal integer exponents (#20530, #20889).

Breaking changes

This section lists changes that do not have deprecation warnings.

  • readline, readlines and eachline return lines without line endings by default. You must use readline(s, chomp=false), etc. to get the old behavior where returned lines include trailing end-of-line character(s) (#19944).

  • Strings no longer have a .data field (as part of a significant performance improvement). Use Vector{UInt8}(str) to access a string as a byte array. However, allocating the Vector object has overhead. You can also use codeunit(str, i) to access the ith byte of a String. Use sizeof(str) instead of length(str.data), and pointer(str) instead of pointer(str.data) (#19449).

  • Operations between Float16 and Integers now return Float16 instead of Float32 (#17261).

  • Keyword arguments are processed left-to-right: if the same keyword is specified more than once, the rightmost occurrence takes precedence (#17785).

  • The lgamma(z) function now uses a different (more standard) branch cut for real(z) < 0, which differs from log(gamma(z)) by multiples of 2π in the imaginary part (#18330).

  • broadcast now handles tuples, and treats any argument that is not a tuple or an array as a "scalar" (#16986).

  • broadcast now produces a BitArray instead of Array{Bool} for functions yielding a boolean result. If you want Array{Bool}, use broadcast! or .= (#17623).

  • Operations like .+ and .* on Range objects are now generic broadcast calls (see above) and produce an Array. If you want a Range result, use + and *, etcetera (#17623).

  • broadcast now treats Ref (except for Ptr) arguments as 0-dimensional arrays (#18965).

  • broadcast now handles missing data (Nullables) allowing operations to be lifted over mixtures of Nullables and scalars, as if the Nullable were like an array with zero or one element (#16961, #19787).

  • The runtime now enforces when new method definitions can take effect (#17057). The flip-side of this is that new method definitions should now reliably actually take effect, and be called when evaluating new code (#265).

  • The array-scalar methods of /, \, *, +, and - now follow broadcast promotion rules. (Likewise for the now-deprecated array-scalar methods of div, mod, rem, &, |, and xor; see "Deprecated or removed" below.) (#19692).

  • broadcast!(f, A) now calls f() for each element of A, rather than doing fill!(A, f()) (#19722).

  • rmprocs now throws an exception if requested workers have not been completely removed before waitfor seconds. With a waitfor=0, rmprocs returns immediately without waiting for worker exits.

  • quadgk has been moved from Base into a separate package (#19741).

  • The Collections module has been removed, and all functions defined therein have been moved to the DataStructures package (#19800).

  • The RepString type has been moved to the LegacyStrings.jl package.

  • In macro calls with parentheses, e.g. @m(a=1), assignments are now parsed as = expressions, instead of as kw expressions (#7669).

  • When used as an infix operator, ~ is now parsed as a call to an ordinary operator with assignment precedence, instead of as a macro call (#20406).

  • (µ "micro" and ɛ "latin epsilon") are considered equivalent to the corresponding Greek characters in identifiers. \varepsilon now tab-completes to U+03B5 (greek small letter epsilon) (#19464).

  • retry now inputs the keyword arguments delays and check instead of n and max_delay. The previous functionality can be achieved setting delays to ExponentialBackOff (#19331).

  • transpose(::AbstractVector) now always returns a RowVector view of the input (which is a special 1×n-sized AbstractMatrix), not a Matrix, etc. In particular, for v::AbstractVector we now have (v.').' === v and v.' * v is a scalar (#19670).

  • Parametric types with "unspecified" parameters, such as Array, are now represented as UnionAll types instead of DataTypes (#18457).

  • Union types have two fields, a and b, instead of a single types field. The empty type Union{} is represented by a singleton of type TypeofBottom (#18457).

  • The type NTuple{N} now refers to tuples where every element has the same type (since it is shorthand for NTuple{N,T} where T). To get the old behavior of matching any tuple, use NTuple{N,Any} (#18457).

  • FloatRange has been replaced by StepRangeLen, and the internal representation of LinSpace has changed. Aside from changes in the internal field names, this leads to several differences in behavior (#18777):

    • Both StepRangeLen and LinSpace can represent ranges of arbitrary object types---they are no longer limited to floating-point numbers.

    • For ranges that produce Float64, Float32, or Float16 numbers, StepRangeLen can be used to produce values with little or no roundoff error due to internal arithmetic that is typically twice the precision of the output result.

    • To take advantage of this precision, linspace(start, stop, len) now returns a range of type StepRangeLen rather than LinSpace when start and stop are FloatNN. LinSpace(start, stop, len) always returns a LinSpace.

    • StepRangeLen(a, step, len) constructs an ordinary-precision range using the values and types of a and step as given, whereas range(a, step, len) will attempt to match inputs a::FloatNN and step::FloatNN to rationals and construct a StepRangeLen that internally uses twice-precision arithmetic. These two outcomes exhibit differences in both precision and speed.

  • A=>B expressions are now parsed as calls instead of using => as the expression head (#20327).

  • The count function no longer sums non-boolean values (#20404)

  • The generic getindex(::AbstractString, ::AbstractVector) method's signature has been tightened to getindex(::AbstractString, ::AbstractVector{<:Integer}). Consequently, indexing into AbstractStrings with non-AbstractVector{<:Integer} AbstractVectors now throws a MethodError in the absence of an appropriate specialization. (Previously such cases failed less explicitly with the exception of AbstractVector{Bool}, which now throws an ArgumentError noting that logical indexing into strings is not supported.) (#20248)

  • Bessel, Hankel, Airy, error, Dawson, eta, zeta, digamma, inverse digamma, trigamma, and polygamma special functions have been moved from Base to the SpecialFunctions.jl package (#20427). Note that airy, airyx and airyprime have been deprecated in favor of more specific functions (airyai, airybi, airyaiprime, airybiprimex, airyaix, airybix, airyaiprimex, airybiprimex) (#18050).

  • When a macro is called in the module in which that macro is defined, global variables in the macro are now correctly resolved in the macro definition environment. Breakage from this change commonly manifests as undefined variable errors that do not occur under 0.5. Fixing such breakage typically requires sprinkling additional escs in the offending macro (#15850).

  • write on an IOBuffer now returns a signed integer in order to be consistent with other buffers (#20609).

  • The <:Integer division fallback /(::Integer, ::Integer), which formerly inappropriately took precedence over other division methods for some mixed-integer-type division calls, has been removed (#19779).

  • @async, @spawn, @spawnat, @fetch and @fetchfrom no longer implicitly localize variables. Previously, the expression would be wrapped in an implicit let block (#19594).

  • parse no longer accepts IPv4 addresses including leading zeros, octal, or hexadecimal. Convert IPv4 addresses including octal or hexadecimal to decimal, and remove leading zeros in decimal addresses (#19811).

  • Closures shipped for remote execution via @spawn or remotecall now automatically serialize globals defined under Main. For details, please refer to the paragraph on "Global variables" under the "Parallel computing" chapter in the manual (#19594).

  • homedir now determines the user's home directory via libuv's uv_os_homedir, rather than from environment variables (#19636).

  • Workers now listen on an ephemeral port assigned by the OS. Previously workers would listen on the first free port available from 9009 (#21818).

Library improvements

  • A new @views macro was added to convert a whole expression or block of code to use views for all slices (#20164).

  • max, min, and related functions (minmax, maximum, minimum, extrema) now return NaN for NaN arguments (#12563).

  • oneunit(x) function to return a dimensionful version of one(x) (which is clarified to mean a dimensionless quantity if x is dimensionful) (#20268).

  • The chop and chomp functions now return a SubString (#18339).

  • Numbered stackframes printed in stacktraces can now be opened in an editor by entering the corresponding number in the REPL and pressing ^Q (#19680).

  • The REPL now supports something called prompt pasting (#17599). This activates when pasting text that starts with julia>  into the REPL. In that case, only expressions starting with julia>  are parsed, the rest are removed. This makes it possible to paste a chunk of code that has been copied from a REPL session without having to scrub away prompts and outputs. This can be disabled or enabled at will with Base.REPL.enable_promptpaste(::Bool).

  • The function print_with_color can now take a color represented by an integer between 0 and 255 inclusive as its first argument (#18473). For a number-to-color mapping, please refer to this chart. It is also possible to use numbers as colors in environment variables that customizes colors in the REPL. For example, to get orange warning messages, simply set ENV["JULIA_WARN_COLOR"] = 208. Please note that not all terminals support 256 colors.

  • The function print_with_color no longer prints text in bold by default (#18628). Instead, the function now take a keyword argument bold::Bool which determines whether to print in bold or not. On some terminals, printing a color in non bold results in slightly darker colors being printed than when printing in bold. Therefore, light versions of the colors are now supported. For the available colors see the help entry on print_with_color.

  • The default text style for REPL input and answers has been changed from bold to normal (#11250). They can be changed back to bold by setting the environment variables JULIA_INPUT_COLOR and JULIA_ANSWER_COLOR to "bold". For example, one way of doing this is adding ENV["JULIA_INPUT_COLOR"] = :bold and ENV["JULIA_ANSWER_COLOR"] = :bold to the .juliarc.jl file. See the manual section on customizing colors for more information.

  • The default color for info messages has been changed from blue to cyan (#18442), and for warning messages from red to yellow (#18453). This can be changed back to the original colors by setting the environment variables JULIA_INFO_COLOR to "blue" and JULIA_WARN_COLOR to "red".

  • Iteration utilities that wrap iterators and return other iterators (enumerate, zip, rest, countfrom, take, drop, cycle, repeated, product, flatten, partition) have been moved to the module Base.Iterators (#18839).

  • BitArrays can now be constructed from arbitrary iterables, in particular from generator expressions, e.g. BitArray(isodd(x) for x = 1:100) (#19018).

  • hcat, vcat, and hvcat now work with UniformScaling objects, so you can now do e.g. [A I] and it will concatenate an appropriately sized identity matrix (#19305).

  • New accumulate and accumulate! functions were added, which generalize cumsum and cumprod. Also known as a scan operation (#18931).

  • reshape now allows specifying one dimension with a Colon() (:) for the new shape, in which case that dimension's length will be computed such that its product with all the other dimensions is equal to the length of the original array (#19919).

  • The new to_indices function provides a uniform interface for index conversions, taking an array and a tuple of indices as arguments and returning a tuple of integers and/or arrays of supported scalar indices. It will throw an ArgumentError for any unsupported indices, and the returned arrays should be iterated over (and not indexed into) to support more efficient logical indexing (#19730).

    • Using colons (:) to represent a collection of indices is deprecated. They now must be explicitly converted to a specialized array of integers with the to_indices function.    As a result, the type of SubArrays that represent views over colon indices has changed.

    • Logical indexing is now more efficient. Logical arrays are converted by to_indices to a lazy, iterable collection of indices that doesn't support indexing. A deprecation provides indexing support with O(n) lookup.

    • The performance of indexing with CartesianIndexes is also improved in many situations.

  • A new titlecase function was added, to capitalize the first character of each word within a string (#19469).

  • any and all now always short-circuit, and mapreduce never short-circuits (#19543). That is, not every member of the input iterable will be visited if a true (in the case of any) or false (in the case of all) value is found, and mapreduce will visit all members of the iterable.

  • Additional methods for ones and zeros functions were added to support the same signature as the similar function (#19635).

  • count now has a count(itr) method equivalent to count(identity, itr) (#20403).

  • Methods for map and filter with Nullable arguments have been implemented; the semantics are as if the Nullable were a container with zero or one elements (#16961).

  • New @test_warn and @test_nowarn macros were added in the Base.Test module to test for the presence or absence of warning messages (#19903).

  • logging can now be used to redirect info, warn, and error messages either universally or on a per-module/function basis (#16213).

  • New function Base.invokelatest(f, args...) to call the latest version of a function in circumstances where an older version may be called instead (e.g. in a function calling eval) (#19784).

  • A new iszero(x) function was added, to quickly check whether x is zero (or is all zeros, for an array) (#19950).

  • notify now returns a count of tasks woken up (#19841).

  • A new nonstandard string literal raw"..." was added, for creating strings with no interpolation or unescaping (#19900).

  • A new Dates.Time type was added that supports representing the time of day with up to nanosecond resolution (#12274).

  • Raising one or negative one to a negative integer power formerly threw a DomainError. One raised to any negative integer power now yields one, negative one raised to any negative even integer power now yields one, and negative one raised to any negative odd integer power now yields negative one. Similarly, raising true to any negative integer power now yields true rather than throwing a DomainError (#18342).

  • A new @macroexpand macro was added as a convenient alternative to the macroexpand function (#18660).

  • invoke now supports keyword arguments (#20345).

  • A new ConjArray type was added, as a wrapper type for lazy complex conjugation of arrays. Currently, it is used by default for the new RowVector type only, and enforces that both transpose(vec) and ctranspose(vec) are views not copies (#20047).

  • rem now accepts a RoundingMode argument via rem(x, y, r::RoundingMode), yielding x - y*round(x/y, r) without intermediate rounding. In particular, rem(x, y, RoundNearest) yields a value in the interval [-abs(y)/2, abs(y)/2]), which corresponds to the IEE754 remainder function. Similarly, rem2pi(x, r::RoundingMode) now exists as well, yielding rem(x, 2pi, r::RoundingMode) but with greater accuracy (#10946).

  • map[!] and broadcast[!] now have dedicated methods for sparse/structured vectors/matrices. Specifically, map[!] and broadcast[!] over combinations including one or more SparseVector, SparseMatrixCSC, Diagonal, Bidiagonal, Tridiagonal, or SymTridiagonal, and any number of broadcast scalars, Vectors, or Matrixs, now efficiently yield SparseVectors or SparseMatrixs as appropriate (#19239, #19371, #19518, #19438, #19690, #19724, #19926, #19934, #20009).

  • The operators ! and ∘ (\circ<tab> at the REPL and in most code editors) now respectively perform predicate function negation and function composition. For example, map(!iszero, (0, 1)) is now equivalent to map(x -> !iszero(x), (0, 1)) and map(uppercase ∘ hex, 250:255) is now equivalent to map(x -> uppercase(hex(x)), 250:255) (#17155).

  • enumerate now supports the two-argument form enumerate(::IndexStyle, iterable). This form allows specification of the returned indices' style. For example, enumerate(IndexLinear, iterable) yields linear indices and enumerate(IndexCartesian, iterable) yields cartesian indices (#16378).

  • Jump to first/last history entries in the REPL via "Alt-<" and "Alt->" (#22829).

Compiler/Runtime improvements

  • ccall is now implemented as a macro, removing the need for special code-generator support for Intrinsics (#18754).

  • ccall gained limited support for a llvmcall calling-convention. This can replace many uses of llvmcall with a simpler, shorter declaration (#18754).

  • All Intrinsics are now Builtin functions instead and have proper error checking and fall-back static compilation support (#18754).

Deprecated or removed

  • ipermutedims(A::AbstractArray, p) has been deprecated in favor of permutedims(A, invperm(p)) (#18891).

  • Linear indexing is now only supported when there is exactly one non-cartesian index provided. Allowing a trailing index at dimension d to linearly access the higher dimensions from array A (beyond size(A, d)) has been deprecated as a stricter constraint during bounds checking. Instead, reshape the array such that its dimensionality matches the number of indices (#20079).

  • Multimedia.@textmime "mime" has been deprecated. Instead define Multimedia.istextmime(::MIME"mime") = true (#18441).

  • isdefined(a::Array, i::Int) has been deprecated in favor of isassigned (#18346).

  • The three-argument SubArray constructor (which accepts dims::Tuple as its third argument) has been deprecated in favor of the two-argument equivalent (the dims::Tuple argument being superfluous) (#19259).

  • is has been deprecated in favor of === (which used to be an alias for is) (#17758).

  • Ambiguous methods for addition and subtraction between UniformScalings and Numbers, for example (+)(J::UniformScaling, x::Number), have been deprecated in favor of unambiguous, explicit equivalents, for example J.λ + x (#17607).

  • num and den have been deprecated in favor of numerator and denominator respectively (#19233,#19246).

  • delete!(ENV::EnvHash, k::AbstractString, def) has been deprecated in favor of pop!(ENV, k, def). Be aware that pop! returns k or def, whereas delete! returns ENV or def (#18012).

  • infix operator $ has been deprecated in favor of infix ⊻ or function xor (#18977).

  • The single-argument form of write (write(x), with implicit STDOUT output stream), has been deprecated in favor of the explicit equivalent write(STDOUT, x) (#17654).

  • Dates.recur has been deprecated in favor of filter (#19288)

  • A number of ambiguous convert operations between Numbers (especially Reals) and Date, DateTime, and Period types have been deprecated in favor of unambiguous convert and explicit constructor calls. Additionally, ambiguous colon construction of <:Period ranges without step specification, for example Dates.Hour(1):Dates.Hour(2), has been deprecated in favor of such construction including step specification, for example Dates.Hour(1):Dates.Hour(1):Dates.Hour(2) (#19920).

  • cummin and cummax have been deprecated in favor of accumulate (#18931).

  • The Array constructor syntax Array(T, dims...) has been deprecated in favor of the forms Array{T,N}(dims...) (where N is known, or particularly Vector{T}(dims...) for N = 1 and Matrix{T}(dims...) for N = 2), and Array{T}(dims...) (where N is not known). Likewise for SharedArrays (#19989).

  • sumabs and sumabs2 have been deprecated in favor of sum(abs, x) and sum(abs2, x), respectively. maxabs and minabs have similarly been deprecated in favor of maximum(abs, x) and minimum(abs, x). Likewise for the in-place counterparts of these functions (#19598).

  • The array-reducing form of isinteger (isinteger(x::AbstractArray)) has been deprecated in favor of all(isinteger, x) (#19925).

  • produce, consume and iteration over a Task object have been deprecated in favor of using Channels for inter-task communication (#19841).

  • The negate keyword has been deprecated from all functions in the Dates adjuster API (adjust, tonext, toprev, Date, Time, and DateTime). Instead use predicate function negation via the ! operator (see Library Improvements) (#20213).

  • @test_approx_eq x y has been deprecated in favor of @test isapprox(x,y) or @test x ≈ y (#4615).

  • Matrix() and Matrix{T}() have been deprecated in favor of the explicit forms Matrix(0, 0) and Matrix{T}(0, 0) (#20330).

  • Vectorized functions have been deprecated in favor of dot syntax (#17302, #17265, #18558, #19711, #19712, #19791, #19802, #19931, #20543, #20228).

  • All methods of character predicates (isalnum, isalpha, iscntrl, isdigit, isnumber, isgraph, islower, isprint, ispunct, isspace, isupper, isxdigit) that accept AbstractStrings have been deprecated in favor of all. For example, isnumber("123") should now be expressed all(isnumber, "123") (#20342).

  • A few names related to indexing traits have been changed: LinearIndexing and linearindexing have been deprecated in favor of IndexStyle. LinearFast has been deprecated in favor of IndexLinear, and LinearSlow has been deprecated in favor of IndexCartesian (#16378).

  • The two-argument forms of map (map!(f, A)) and asyncmap! (asyncmap!(f, A)) have been deprecated in anticipation of future semantic changes (#19721).

  • unsafe_wrap(String, ...) has been deprecated in favor of unsafe_string (#19449).

  • zeros and ones methods accepting an element type as the first argument and an array as the second argument, for example zeros(Float64, [1, 2, 3]), have been deprecated in favor of equivalent methods with the second argument instead the size of the array, for example zeros(Float64, size([1, 2, 3])) (#21183).

  • Base.promote_eltype_op has been deprecated (#19669, #19814, #19937).

  • isimag has been deprecated (#19949).

  • The tuple-of-types form of invoke, invoke(f, (types...), ...), has been deprecated in favor of the tuple-type form invoke(f, Tuple{types...}, ...) (#18444).

  • Base._promote_array_type has been deprecated (#19766).

  • broadcast_zpreserving has been deprecated (#19533, #19720).

  • Methods allowing indexing of tuples by AbstractArrays with more than one dimension have been deprecated. (Indexing a tuple by such a higher-dimensional AbstractArray should yield a tuple with more than one dimension, but tuples are one-dimensional.) (#19737).

  • @test_approx_eq a b has been deprecated in favor of @test a ≈ b (or, equivalently, @test ≈(a, b) or @test isapprox(a, b)). @test_approx_eq_eps has been deprecated in favor of new @test syntax: @test now supports the syntax @test f(args...) key=val ... for @test f(args..., key=val...). This syntax allows, for example, writing @test a ≈ b atol=c in place of @test ≈(a, b, atol=c) (and hence @test_approx_eq_eps a b c) (#19901).

  • takebuf_array has been deprecated in favor of take!, and takebuf_string(x) has been deprecated in favor of String(take!(x)) (#19088).

  • convert methods from Diagonal and Bidiagonal to subtypes of AbstractTriangular have been deprecated (#17723).

  • Base.LinAlg.arithtype has been deprecated. If you were using arithtype within a promote_op call, instead use promote_op(Base.LinAlg.matprod, Ts...). Otherwise, consider defining equivalent functionality locally (#18218).

  • Special characters (#{}()[]<>|&*?~;) should now be quoted in commands. For example, `export FOO=1\;` should replace `export FOO=1;` and `cd $dir '&&' $thingie` should replace `cd $dir && $thingie` (#19786).

  • Zero-argument Channel constructors (Channel(), Channel{T}()) have been deprecated in favor of equivalents accepting an explicit Channel size (Channel(2), Channel{T}(2)) (#18832).

  • The zero-argument constructor MersenneTwister() has been deprecated in favor of the explicit MersenneTwister(0) (#16984).

  • Base.promote_type(op::Type, Ts::Type...) has been removed as part of an overhaul of broadcast's promotion mechanism. If you need the functionality of that Base.promote_type method, consider defining it locally via Core.Inference.return_type(op, Tuple{Ts...}) (#18642).

  • bitbroadcast has been deprecated in favor of broadcast, which now produces a BitArray instead of Array{Bool} for functions yielding a boolean result (#19771).

  • To complete the deprecation of histogram-related functions, midpoints has been deprecated. Instead use the StatsBase.jl package's midpoints function (#20058).

  • Passing a type argument to LibGit2.cat has been deprecated in favor of a simpler, two-argument method for LibGit2.cat (#20435).

  • The LibGit2.owner function for finding the repository which owns a given Git object has been deprecated in favor of LibGit2.repository (#20135).

  • The LibGit2.GitAnyObject type has been renamed to LibGit2.GitUnknownObject to clarify its intent (#19935).

  • The LibGit2.GitOid type has been renamed to LibGit2.GitHash for clarity (#19878).

  • Finalizing LibGit2 objects with finalize has been deprecated in favor of using close (#19660).

  • Parsing string dates from a Dates.DateFormat object has been deprecated as part of a larger effort toward faster, more extensible date parsing (#20952).

Command-line option changes

  • In polly builds (USE_POLLY := 1), the new flag --polly={yes|no} controls whether @polly declarations are respected. (With --polly=no, @polly declarations are ignored.) This flag is also available in non-polly builds (USE_POLLY := 0), but has no effect (#18159).