# Internals & Design

**URL:** https://discourse.julialang.org/c/dev/5.md?page=44

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**Page:** 45

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## [What happens if Julia Computing goes away?](https://discourse.julialang.org/t/what-happens-if-julia-computing-goes-away/28136)

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**Author:** [@ninjaaron](https://discourse.julialang.org/u/ninjaaron)\
**Replies:** 18\
**Last updated:** [September 5, 2019, 10:45am UTC](https://discourse.julialang.org/t/what-happens-if-julia-computing-goes-away/28136 "2019-09-05T10:45:41Z")

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So, I’m mostly a private Julia user. I like it very much, and I try to contribute to the community with docs and code, but I’m not really in a situation to purchase anything from Julia Computing. I had a candid conversat…

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## [How does REPL helpmode work?](https://discourse.julialang.org/t/how-does-repl-helpmode-work/28244)

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**Author:** [@tgf314](https://discourse.julialang.org/u/tgf314)\
**Replies:** 2\
**Last updated:** [August 31, 2019, 11:26pm UTC](https://discourse.julialang.org/t/how-does-repl-helpmode-work/28244 "2019-08-31T23:26:30Z")

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If I type the following: using REPL REPL.\_helpmode( "push!" ) I get the following output: :(#= /home/flynn/projects/julia/julia-1.1/usr/share/julia/stdlib/v1.1/REPL/src/docview.jl:40 =# (REPL).@repl Base.TTY(RawFD(0x0…

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## [When to migrate to 1.2-style test-specific dependencies](https://discourse.julialang.org/t/when-to-migrate-to-1-2-style-test-specific-dependencies/28205)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 3\
**Last updated:** [August 30, 2019, 7:11pm UTC](https://discourse.julialang.org/t/when-to-migrate-to-1-2-style-test-specific-dependencies/28205 "2019-08-30T19:11:19Z")

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Are the semantics for test-specific dependencies with test/Project.toml still being finalized? Who should migrate at this point? (eg adventurous users who don’t mind if things break or change, or more conservative ones …

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## [Code isolation side discussion](https://discourse.julialang.org/t/code-isolation-side-discussion/28108)

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**Author:** [@TsurHerman](https://discourse.julialang.org/u/TsurHerman)\
**Replies:** 14\
**Last updated:** [August 29, 2019, 4:19pm UTC](https://discourse.julialang.org/t/code-isolation-side-discussion/28108 "2019-08-29T16:19:03Z")

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It seems to me that: This is a security liability for the language, meaning it can not be used in anything critical. Which is another reason why I think that some form of isolation like I proposed in contextual dispat…

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## [\[Possible Bug?\] Weird behavior with small negative indices in findnext()](https://discourse.julialang.org/t/possible-bug-weird-behavior-with-small-negative-indices-in-findnext/28057)

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**Author:** [@AndrewQuinn2020](https://discourse.julialang.org/u/AndrewQuinn2020)\
**Replies:** 3\
**Last updated:** [August 28, 2019, 12:02pm UTC](https://discourse.julialang.org/t/possible-bug-weird-behavior-with-small-negative-indices-in-findnext/28057 "2019-08-28T12:02:03Z")

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Take a look at this, y’all, and tell me if this is a bug – I’ll step up later this week to fix it and write some @tests for it if so. julia\> versioninfo() Julia Version 1.2.0 Commit c6da87ff4b (2019-08-20 00:03 UTC) Pla…

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## [Python \`collections.ChainMap\` equivalent?](https://discourse.julialang.org/t/python-collections-chainmap-equivalent/27990)

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**Author:** [@singularitti](https://discourse.julialang.org/u/singularitti)\
**Replies:** 4\
**Last updated:** [August 27, 2019, 12:51am UTC](https://discourse.julialang.org/t/python-collections-chainmap-equivalent/27990 "2019-08-27T00:51:30Z")

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Python’s collections.ChainMap class groups multiple dicts or other mappings together to create a single, updateable view. So it is suitable to let user-specified command-line arguments take precedence over environment va…

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## [Nested getproperty requests](https://discourse.julialang.org/t/nested-getproperty-requests/27968)

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**Author:** [@ablaom](https://discourse.julialang.org/u/ablaom)\
**Replies:** 2\
**Last updated:** [August 26, 2019, 6:39am UTC](https://discourse.julialang.org/t/nested-getproperty-requests/27968 "2019-08-26T06:39:47Z")

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I have a use for accessing and setting nested properties of julia objects. To achieve this, I have the code below in a package. I have been reasonably accused of type piracy and wondered: (i) if others agree this is dang…

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## [BigFloat struct size is larger than mpfr\_t](https://discourse.julialang.org/t/bigfloat-struct-size-is-larger-than-mpfr-t/27596)

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**Author:** [@MikaelSlevinsky](https://discourse.julialang.org/u/MikaelSlevinsky)\
**Replies:** 9\
**Last updated:** [August 23, 2019, 11:37pm UTC](https://discourse.julialang.org/t/bigfloat-struct-size-is-larger-than-mpfr-t/27596 "2019-08-23T23:37:50Z")

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The Julia BigFloat struct has an extra field, \_d, compared with the corresponding MPFR type mpfr\_t. This doesn’t affect Base because the additional field is at the end of the type. However, one disadvantage is that sizeo…

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## [Why \`using Makie; lines(rand(5));\` using sysimage generated from precompiles is about 5 times slower than \`compile\_incremental(:Makie, :AbstractPlotting)\`?](https://discourse.julialang.org/t/why-using-makie-lines-rand-5-using-sysimage-generated-from-precompiles-is-about-5-times-slower-than-compile-incremental-makie-abstractplotting/27808)

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**Author:** [@KestutisMa](https://discourse.julialang.org/u/KestutisMa)\
**Replies:** 1\
**Last updated:** [August 23, 2019, 12:47pm UTC](https://discourse.julialang.org/t/why-using-makie-lines-rand-5-using-sysimage-generated-from-precompiles-is-about-5-times-slower-than-compile-incremental-makie-abstractplotting/27808 "2019-08-23T12:47:18Z")

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Makie.lines(rand(5)); is about 5 times slower after Fezzik.brute\_build\_julia() than PackageCompiler.compile\_incremental(:Makie, :AbstractPlotting). In contrast, s = Scene() is same fast. Fezzik uses PackageCompiler…

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## [Fgpa + Julia?](https://discourse.julialang.org/t/fgpa-julia/27780)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 1\
**Last updated:** [August 21, 2019, 9:32pm UTC](https://discourse.julialang.org/t/fgpa-julia/27780 "2019-08-21T21:32:23Z")

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I was pretty excited when I saw this tweet by Keno https://twitter.com/KenoFischer/status/1154865907472183296?s=19 which is showing Julia on Fgpa. And I also see papers like this where FGPA are used to do data work eg …

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## [$ interpolation into :()](https://discourse.julialang.org/t/interpolation-into/27806)

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**Author:** [@bkamins](https://discourse.julialang.org/u/bkamins)\
**Replies:** 4\
**Last updated:** [August 21, 2019, 8:48pm UTC](https://discourse.julialang.org/t/interpolation-into/27806 "2019-08-21T20:48:22Z")

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Consider the following code: julia\> nt = (x=1, y=2) (x = 1, y = 2) julia\> k1 = keys(nt)\[1\] :x julia\> :($k1) :x julia\> :($(keys(nt)\[1\])) :x julia\> nt.:($k1) 1 julia\> nt.:($(keys(nt)\[1\])) ERROR: syntax: invalid synta…

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## [FemtoCleaner.jl needs help for updating to Julia 1.x syntax/features](https://discourse.julialang.org/t/femtocleaner-jl-needs-help-for-updating-to-julia-1-x-syntax-features/27787)

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**Author:** [@XVilka](https://discourse.julialang.org/u/XVilka)\
**Replies:** 0\
**Last updated:** [August 21, 2019, 5:05am UTC](https://discourse.julialang.org/t/femtocleaner-jl-needs-help-for-updating-to-julia-1-x-syntax-features/27787 "2019-08-21T05:05:05Z")

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Overall the project seems abandoned - no updates for a year, PRs are not getting merged and update to Julia 1.x needs your help. See more information at the Issues and Pull Requests repository pages. Would be nice if mai…

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## [Suggest installing un-installed packages](https://discourse.julialang.org/t/suggest-installing-un-installed-packages/27747)

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**Author:** [@tlienart](https://discourse.julialang.org/u/tlienart)\
**Replies:** 4\
**Last updated:** [August 20, 2019, 1:48pm UTC](https://discourse.julialang.org/t/suggest-installing-un-installed-packages/27747 "2019-08-20T13:48:22Z")

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Maybe I’m just lazy and a bit averse to error messages but julia\> using SomePackageThatIDontHave ERROR: ArgumentError: Package SomePackageThatIDontHave not found in current path: - Run \`import Pkg; Pkg.add("SomePackageT…

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## [Pkg3 and standard libraries](https://discourse.julialang.org/t/pkg3-and-standard-libraries/9287)

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**Author:** [@dmbates](https://discourse.julialang.org/u/dmbates)\
**Replies:** 21\
**Last updated:** [August 18, 2019, 6:44am UTC](https://discourse.julialang.org/t/pkg3-and-standard-libraries/9287 "2019-08-18T06:44:14Z")

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Encouraged by a commit message on the main repository I started using Pkg3 on my locally compiled version of master. I am working on revisions to the PDMats package for Julia v0.7 so I begin with using LinearAlgebra w…

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## [\`consttype\` keyword](https://discourse.julialang.org/t/consttype-keyword/27497)

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**Author:** [@gdkrmr](https://discourse.julialang.org/u/gdkrmr)\
**Replies:** 2\
**Last updated:** [August 13, 2019, 12:33pm UTC](https://discourse.julialang.org/t/consttype-keyword/27497 "2019-08-13T12:33:35Z")

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Has this ever been proposed? What about adding a consttype keyword, that forces a value to have a certain type: julia\> consttype x = 3 3 julia\> x = 1.5 Error: x must be of type Int # alternatively convert as in array …

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## [Threading 1.3: Success Story](https://discourse.julialang.org/t/threading-1-3-success-story/27111)

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**Author:** [@tobias.knopp](https://discourse.julialang.org/u/tobias.knopp)\
**Replies:** 16\
**Last updated:** [August 9, 2019, 12:38am UTC](https://discourse.julialang.org/t/threading-1-3-success-story/27111 "2019-08-09T00:38:14Z")

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Dear @jeff.bezanson and @jameson. Just want to share a success story for the new threading infrastructure (1.3 alpha). The focus in your Juliacon talk seemed to be primary on performance but from my perspective a very im…

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## [Canvas in Gtk doesn't work while the loop is running](https://discourse.julialang.org/t/canvas-in-gtk-doesnt-work-while-the-loop-is-running/15398)

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**Author:** [@dsHitman](https://discourse.julialang.org/u/dsHitman)\
**Replies:** 9\
**Last updated:** [August 8, 2019, 8:20am UTC](https://discourse.julialang.org/t/canvas-in-gtk-doesnt-work-while-the-loop-is-running/15398 "2019-08-08T08:20:39Z")

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I’m trying to create a “game of life” with GUI (using Gtk.jl) but while the loop is running the canvas doesn’t work (the Windows is not visible,as if it was minimized) anyone knows why?

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## [\`Base.Printf.ini\_dec\` has a fall-thru issue](https://discourse.julialang.org/t/base-printf-ini-dec-has-a-fall-thru-issue/27247)

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**Author:** [@JeffreySarnoff](https://discourse.julialang.org/u/JeffreySarnoff)\
**Replies:** 1\
**Last updated:** [August 7, 2019, 1:04pm UTC](https://discourse.julialang.org/t/base-printf-ini-dec-has-a-fall-thru-issue/27247 "2019-08-07T13:04:10Z")

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Some of my more precise floating point types do not properly know how to overload Base.Printf.ini\_dec or any of its very close algorithmic partners Printf.fix\_dec Printf.decode\_dec (nor which of those should be given spe…

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## [Release-1.3 branch date approaching: Aug. 15](https://discourse.julialang.org/t/release-1-3-branch-date-approaching-aug-15/27233)

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**Author:** [@jeff.bezanson](https://discourse.julialang.org/u/jeff.bezanson)\
**Replies:** 0\
**Last updated:** [August 6, 2019, 6:04pm UTC](https://discourse.julialang.org/t/release-1-3-branch-date-approaching-aug-15/27233 "2019-08-06T18:04:38Z")

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Hello all, We are targeting Aug. 15 as the feature freeze / branch date for 1.3. This is roughly 4 months after the branch date for 1.2, in keeping with our usual release schedule. If you have any PRs or such that are c…

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## [Custom tuple unpacking](https://discourse.julialang.org/t/custom-tuple-unpacking/27224)

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**Author:** [@manuelma](https://discourse.julialang.org/u/manuelma)\
**Replies:** 1\
**Last updated:** [August 6, 2019, 3:30pm UTC](https://discourse.julialang.org/t/custom-tuple-unpacking/27224 "2019-08-06T15:30:02Z")

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I would like to be able to write something like x, y, z = collect(I) and then have z == collect(I)\[3:end\]. In other words, I’d like to unpack the entire ‘tail’ of I into the last value on the left hand side. I don’t k…

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## [How to implement the Python's \`itertools.tee\` function](https://discourse.julialang.org/t/how-to-implement-the-pythons-itertools-tee-function/27142)

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**Author:** [@singularitti](https://discourse.julialang.org/u/singularitti)\
**Replies:** 3\
**Last updated:** [August 5, 2019, 12:37am UTC](https://discourse.julialang.org/t/how-to-implement-the-pythons-itertools-tee-function/27142 "2019-08-05T00:37:39Z")

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Python’s doc has given a roughly equivalent to its itertools.tee function: def tee(iterable, n=2): it = iter(iterable) deques = \[collections.deque() for i in range(n)\] def gen(mydeque): while True: …

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## [Multi-threaded tasks, external multi-threaded code, avoiding oversubscription](https://discourse.julialang.org/t/multi-threaded-tasks-external-multi-threaded-code-avoiding-oversubscription/26887)

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**Author:** [@oschulz](https://discourse.julialang.org/u/oschulz)\
**Replies:** 2\
**Last updated:** [July 28, 2019, 9:16am UTC](https://discourse.julialang.org/t/multi-threaded-tasks-external-multi-threaded-code-avoiding-oversubscription/26887 "2019-07-28T09:16:38Z")

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Regarding the new tread scheduler and external code that uses threads (discussed a lot at JC19) - just a thought I had, no idea if it’s feasible: What if a partr task could (optionally) request more than one thread? Kin…

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## [Indexing with \`CartesianIndex\`](https://discourse.julialang.org/t/indexing-with-cartesianindex/26615)

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**Author:** [@bkamins](https://discourse.julialang.org/u/bkamins)\
**Replies:** 14\
**Last updated:** [July 23, 2019, 5:52pm UTC](https://discourse.julialang.org/t/indexing-with-cartesianindex/26615 "2019-07-23T17:52:05Z")

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Consider this code: julia\> 1\[\] 1 julia\> 1\[CartesianIndex()\] 1 julia\> Ref(1)\[\] 1 julia\> Ref(1)\[CartesianIndex()\] ERROR: MethodError: no method matching getindex(::Base.RefValue{Int64}, ::CartesianIndex{0}) Is there a…

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## [Extremely long compilation time (\> 2000 sec on Win32)](https://discourse.julialang.org/t/extremely-long-compilation-time-2000-sec-on-win32/26496)

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**Author:** [@devmotion](https://discourse.julialang.org/u/devmotion)\
**Replies:** 13\
**Last updated:** [July 21, 2019, 10:19am UTC](https://discourse.julialang.org/t/extremely-long-compilation-time-2000-sec-on-win32/26496 "2019-07-21T10:19:48Z")

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Hej! I’m observing extremely long compilation times of more than 2000 sec on Appveyor (Win32) for the delay differential equation solver package DelayDiffEq. A week ago, with version 5.7.0 the first test took around 16…

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## [Philosophy on asserts](https://discourse.julialang.org/t/philosophy-on-asserts/26587)

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**Author:** [@lewis](https://discourse.julialang.org/u/lewis)\
**Replies:** 5\
**Last updated:** [July 21, 2019, 5:54am UTC](https://discourse.julialang.org/t/philosophy-on-asserts/26587 "2019-07-21T05:54:45Z")

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Curious what the view on asserts in released, production code is. Working on PR for Pkg.TOML. It has lots of places that trigger assert error on nothing values with a get method: get(x) = (@assert !isnull(x); x). In t…

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## [@sync block drops asynchronous errors in favor of synchronous errors](https://discourse.julialang.org/t/sync-block-drops-asynchronous-errors-in-favor-of-synchronous-errors/26440)

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**Author:** [@Jasha10](https://discourse.julialang.org/u/Jasha10)\
**Replies:** 2\
**Last updated:** [July 17, 2019, 7:25am UTC](https://discourse.julialang.org/t/sync-block-drops-asynchronous-errors-in-favor-of-synchronous-errors/26440 "2019-07-17T07:25:04Z")

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The @sync macro creates an array Any\[\] that is used to keep track of any @async tasks that are created within the (lexically-scoped) @sync block. After the code in the @sync block runs, the Base.sync\_end function is call…

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## [MKL: what are the issues these days?](https://discourse.julialang.org/t/mkl-what-are-the-issues-these-days/18191)

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**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 13\
**Last updated:** [July 16, 2019, 1:17pm UTC](https://discourse.julialang.org/t/mkl-what-are-the-issues-these-days/18191 "2019-07-16T13:17:01Z")

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I understand the JuliaPro does not ship MKL version anymore. There is an explanation of the situation in 2016 by @StefanKarpinski : This is not a technical issue primarily, it’s a legal one. You can easily build Julia w…

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## [Auto-conversion of keyword arguments, status?](https://discourse.julialang.org/t/auto-conversion-of-keyword-arguments-status/26350)

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**Author:** [@oschulz](https://discourse.julialang.org/u/oschulz)\
**Replies:** 2\
**Last updated:** [July 15, 2019, 4:25am UTC](https://discourse.julialang.org/t/auto-conversion-of-keyword-arguments-status/26350 "2019-07-15T04:25:06Z")

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I know there have been some discussions (and issues) about this in the past, but I’m curious what the current position on “auto-conversions for keyword arguments” is. Is that something that will/could be added in future…

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## [Argument order for setindex! and setproperty! not consistent](https://discourse.julialang.org/t/argument-order-for-setindex-and-setproperty-not-consistent/26293)

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**Author:** [@dstarerstor](https://discourse.julialang.org/u/dstarerstor)\
**Replies:** 6\
**Last updated:** [July 14, 2019, 3:04am UTC](https://discourse.julialang.org/t/argument-order-for-setindex-and-setproperty-not-consistent/26293 "2019-07-14T03:04:18Z")

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This is really minor, but I happened to notice that the argument order is not consistent between setindex! and setproperty!. For example, the methods setindex!(A::Array{Any,N} where N, x, i::Int64) in Base at essentials…

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## [Is there a discrepancy betweeen use of :: and \<: in function versus struct definitions](https://discourse.julialang.org/t/is-there-a-discrepancy-betweeen-use-of-and-in-function-versus-struct-definitions/26304)

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**Author:** [@robot-uprising](https://discourse.julialang.org/u/robot-uprising)\
**Replies:** 2\
**Last updated:** [July 13, 2019, 12:04am UTC](https://discourse.julialang.org/t/is-there-a-discrepancy-betweeen-use-of-and-in-function-versus-struct-definitions/26304 "2019-07-13T00:04:54Z")

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for example: function foo(x::Real) … end struct bar{N\<:Real} x::N end Why use :: for function, and \<: for struct? I get an error with: struct bar{N::Real} x::N end

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