# Internals & Design

**URL:** https://discourse.julialang.org/c/dev/5.md?no_subcategories=false&page=10

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**Page:** 11

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## [IRCE appreciation and gripes (inductive range check elimination)](https://discourse.julialang.org/t/irce-appreciation-and-gripes-inductive-range-check-elimination/111822)

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**Author:** [@foobar\_lv2](https://discourse.julialang.org/u/foobar_lv2)\
**Replies:** 3\
**Last updated:** [March 19, 2024, 4:54pm UTC](https://discourse.julialang.org/t/irce-appreciation-and-gripes-inductive-range-check-elimination/111822 "2024-03-19T16:54:47Z")

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IRCE is an LLVM pass that aims to loop unswitch range checks. As such, its goal is to reduce the performance impact of bounds checks – especially missing @inbounds should no longer prevent vectorization. To give a simpl…

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## [Borrow checker with GC fallback?](https://discourse.julialang.org/t/borrow-checker-with-gc-fallback/111798)

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**Author:** [@Tarny\_GG\_Channie](https://discourse.julialang.org/u/Tarny_GG_Channie)\
**Replies:** 4\
**Last updated:** [March 19, 2024, 4:12pm UTC](https://discourse.julialang.org/t/borrow-checker-with-gc-fallback/111798 "2024-03-19T16:12:39Z")

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GC incurs some overhead. It’d be nice if we don’t have to GC everything. In some cases, we can detect exactly when the memory needs to be freed at compile time. If so, would it be a good idea? Julia is a language that wa…

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## [Where should Julia feature requests go?](https://discourse.julialang.org/t/where-should-julia-feature-requests-go/102835)

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**Author:** [@gdalle](https://discourse.julialang.org/u/gdalle)\
**Replies:** 41\
**Last updated:** [March 18, 2024, 10:34am UTC](https://discourse.julialang.org/t/where-should-julia-feature-requests-go/102835 "2024-03-18T10:34:32Z")

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The PR by @Sukera on a new issue template triggered a wider discussion about what GitHub issues are for, and how they should be used in the Julia language repo. On the aspect of feature requests, @viralbshah said the fol…

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## [Manual type inference of hand-written IRCode](https://discourse.julialang.org/t/manual-type-inference-of-hand-written-ircode/106356)

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**Author:** [@Tomas\_Pevny](https://discourse.julialang.org/u/Tomas_Pevny)\
**Replies:** 10\
**Last updated:** [March 15, 2024, 8:02am UTC](https://discourse.julialang.org/t/manual-type-inference-of-hand-written-ircode/106356 "2024-03-15T08:02:19Z")

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Hello, i am trying to write something like Petite Zygote by manipulating Core.Compiler.IRCode to get sense, how it works. I am considering that as a part of survey, if I should show it to students, where the compiler in…

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## [How to use julia parser out of julia](https://discourse.julialang.org/t/how-to-use-julia-parser-out-of-julia/111438)

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**Author:** [@hsolerkalinovski](https://discourse.julialang.org/u/hsolerkalinovski)\
**Replies:** 8\
**Last updated:** [March 11, 2024, 11:16pm UTC](https://discourse.julialang.org/t/how-to-use-julia-parser-out-of-julia/111438 "2024-03-11T23:16:00Z")

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Hello, and thanks for dedicating your time at reading my question, even if you can’t help em regarding it. For the couple past months, I’ve been enrolled in a project where I must analyze code change patterns in open so…

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## [\`Libdl.dlopen\` versus \`dlfcn.h\`'s \`dlopen\`](https://discourse.julialang.org/t/libdl-dlopen-versus-dlfcn-h-s-dlopen/111331)

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**Author:** [@goretkin](https://discourse.julialang.org/u/goretkin)\
**Replies:** 3\
**Last updated:** [March 8, 2024, 1:26pm UTC](https://discourse.julialang.org/t/libdl-dlopen-versus-dlfcn-h-s-dlopen/111331 "2024-03-08T13:26:12Z")

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On my system, I see // Build with // \`gcc test\_libpython.c -ldl\` #include \<stdio.h\> #include \<dlfcn.h\> int main() { void\* handle = dlopen("/usr/lib/x86\_64-linux-gnu/libpython3.10.so.1.0", RTLD\_LAZY | RTLD\_DEEPBIND…

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## [Generated functions and reflection](https://discourse.julialang.org/t/generated-functions-and-reflection/111301)

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**Author:** [@willtebbutt](https://discourse.julialang.org/u/willtebbutt)\
**Replies:** 1\
**Last updated:** [March 7, 2024, 9:49pm UTC](https://discourse.julialang.org/t/generated-functions-and-reflection/111301 "2024-03-07T21:49:50Z")

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Why is it the case that reflection is not permitted from within generated functions? (I know that e.g. Zygote does it, but I get the impression that’s frowned upon). I had a search through old posts but can’t find a clea…

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## [Linear relationship between Xoshiro tasks](https://discourse.julialang.org/t/linear-relationship-between-xoshiro-tasks/110454)

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**Author:** [@foobar\_lv2](https://discourse.julialang.org/u/foobar_lv2)\
**Replies:** 29\
**Last updated:** [March 6, 2024, 4:39pm UTC](https://discourse.julialang.org/t/linear-relationship-between-xoshiro-tasks/110454 "2024-03-06T16:39:36Z")

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Cool, I didn’t see that! Quite sweet addition to my initial unprincipled PR. However, I fear that your construction is somewhat broken. The problem is that you can easily construct task trees that imply linear relatio…

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## [Naming of ScopedValues](https://discourse.julialang.org/t/naming-of-scopedvalues/110747)

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**Author:** [@mnemnion](https://discourse.julialang.org/u/mnemnion)\
**Replies:** 26\
**Last updated:** [March 7, 2024, 7:29pm UTC](https://discourse.julialang.org/t/naming-of-scopedvalues/110747 "2024-03-07T19:29:41Z")

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A bit off topic, but it confuses me that my old friend from Lisp, the \*dynamic-variable\*, is called ScopedValue in Julia. I gather that’s what they’re called in Java? My gripe is that what differs between lexical scope…

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## [Expose credential methods from LibGit2 in Pkg.jl](https://discourse.julialang.org/t/expose-credential-methods-from-libgit2-in-pkg-jl/111261)

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**Author:** [@lklein](https://discourse.julialang.org/u/lklein)\
**Replies:** 0\
**Last updated:** [March 6, 2024, 9:11pm UTC](https://discourse.julialang.org/t/expose-credential-methods-from-libgit2-in-pkg-jl/111261 "2024-03-06T21:11:49Z")

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LibGit2 offers some opportunities to Manage credentials explicitly (SSHCredential and UserPasswordCredential for example). Has there ever been made any effort to expose those to the user of Pkg.jl? Or if not does anyone…

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## [Build Julia with debug files](https://discourse.julialang.org/t/build-julia-with-debug-files/111131)

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**Author:** [@Luc\_W](https://discourse.julialang.org/u/Luc_W)\
**Replies:** 0\
**Last updated:** [March 4, 2024, 12:33pm UTC](https://discourse.julialang.org/t/build-julia-with-debug-files/111131 "2024-03-04T12:33:52Z")

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Is there a way to enable generating debug info with the release build. I know that you can build a debug version in cygwin with “make -j 4 debug” but this will append “-debug” to julia.exe and some dll’s. I tried removin…

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## [Why are self-referential struct parameters impossible?](https://discourse.julialang.org/t/why-are-self-referential-struct-parameters-impossible/110982)

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**Author:** [@mnemnion](https://discourse.julialang.org/u/mnemnion)\
**Replies:** 19\
**Last updated:** [March 2, 2024, 11:46pm UTC](https://discourse.julialang.org/t/why-are-self-referential-struct-parameters-impossible/110982 "2024-03-02T23:46:18Z")

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Neither of these compiles: struct Tree{V\<:Any,T\<:Union{Tree,Nothing}} value::V left::T right::T end struct Tree{V,T} where {V\<:Any,T\<:Union{Tree,Nothing}} value::V left::T right::T end It m…

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## [\`in\` vs \`=\` in loop expressions](https://discourse.julialang.org/t/in-vs-in-loop-expressions/110569)

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**Author:** [@Mason](https://discourse.julialang.org/u/Mason)\
**Replies:** 3\
**Last updated:** [February 25, 2024, 2:34am UTC](https://discourse.julialang.org/t/in-vs-in-loop-expressions/110569 "2024-02-25T02:34:22Z")

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Continuing the discussion from Supporting syntax \`x not in y\` as alias for \`!(x in y)\`: While I agree, I will note that the parser disagrees with you, and literally does treat in as syntactic sugar for = in loop expres…

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## [Reason for duplicated llvm code in pseudo-vtable](https://discourse.julialang.org/t/reason-for-duplicated-llvm-code-in-pseudo-vtable/110719)

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**Author:** [@wheeheee](https://discourse.julialang.org/u/wheeheee)\
**Replies:** 7\
**Last updated:** [February 25, 2024, 11:45pm UTC](https://discourse.julialang.org/t/reason-for-duplicated-llvm-code-in-pseudo-vtable/110719 "2024-02-25T23:45:45Z")

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Apologies if this is answered somewhere else, but I couldn’t find it. I have the following two functions; testvt is intended to do some sort of dispatch, while remaining type-stable: @noinline f(x, a, b, c, ::Val{N}) w…

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## [LXM splittable prng](https://discourse.julialang.org/t/lxm-splittable-prng/110501)

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**Author:** [@jar1](https://discourse.julialang.org/u/jar1)\
**Replies:** 5\
**Last updated:** [February 23, 2024, 10:42pm UTC](https://discourse.julialang.org/t/lxm-splittable-prng/110501 "2024-02-23T22:42:29Z")

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Continuing the discussion from Linear relationship between Xoshiro tasks: Just in case it’s interesting, Guy Steele who worked on SplitMix has come up with a newer algorithm. Talk: https://www.youtube.com/watch?v=OXurC…

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## [Supporting syntax \`x not in y\` as alias for \`!(x in y)\`](https://discourse.julialang.org/t/supporting-syntax-x-not-in-y-as-alias-for-x-in-y/110146)

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**Author:** [@fingolfin](https://discourse.julialang.org/u/fingolfin)\
**Replies:** 48\
**Last updated:** [February 23, 2024, 7:01am UTC](https://discourse.julialang.org/t/supporting-syntax-x-not-in-y-as-alias-for-x-in-y/110146 "2024-02-23T07:01:17Z")

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One thing I like in Python is that they allow writing x not in y instead of !(x in y). To me this results in code that is much easier to read (obviously this is subjective). I wonder if it would be possible to support t…

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## [Julia Pragma Macros](https://discourse.julialang.org/t/julia-pragma-macros/110532)

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**Author:** [@mnemnion](https://discourse.julialang.org/u/mnemnion)\
**Replies:** 4\
**Last updated:** [February 21, 2024, 7:33pm UTC](https://discourse.julialang.org/t/julia-pragma-macros/110532 "2024-02-21T19:33:22Z")

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Continuing the discussion from Ifelse vs ternary with tuples: Julia has a few “pragma macros” already and I agree more would be nice. The current collection, such as @inline and @inbounds/@boundscheck, focus on compil…

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## [Inferring MethodInstance from code\_llvm](https://discourse.julialang.org/t/inferring-methodinstance-from-code-llvm/110330)

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**Author:** [@dyatunin](https://discourse.julialang.org/u/dyatunin)\
**Replies:** 5\
**Last updated:** [February 20, 2024, 3:51am UTC](https://discourse.julialang.org/t/inferring-methodinstance-from-code-llvm/110330 "2024-02-20T03:51:38Z")

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I am trying to track down some performance issues by tracing through the output of code\_llvm. Whenever the LLVM code contains a call to a Julia function, I would like to figure out which MethodInstance of that function i…

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## [Did Logging lose colors on Julia 1.11?](https://discourse.julialang.org/t/did-logging-lose-colors-on-julia-1-11/110416)

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**Author:** [@mkitti](https://discourse.julialang.org/u/mkitti)\
**Replies:** 1\
**Last updated:** [February 19, 2024, 7:27pm UTC](https://discourse.julialang.org/t/did-logging-lose-colors-on-julia-1-11/110416 "2024-02-19T19:27:25Z")

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My log messages seem to have lost their color. Is this happening for anyone else on nightly?

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## [RFC: Some Ideas to Tackle #15276 - performance of captured variables in closures](https://discourse.julialang.org/t/rfc-some-ideas-to-tackle-15276-performance-of-captured-variables-in-closures/95260)

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**Author:** [@uniment](https://discourse.julialang.org/u/uniment)\
**Replies:** 65\
**Last updated:** [February 16, 2024, 8:56pm UTC](https://discourse.julialang.org/t/rfc-some-ideas-to-tackle-15276-performance-of-captured-variables-in-closures/95260 "2024-02-16T20:56:29Z")

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Naïvely written Julia should be performant. It shouldn’t take memorizing a 35-page manual to reliably beat Matlab. Unless more performance footguns are removed, it’s impossible for a package ecosystem to be performant. F…

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## [1.11 feature freeze, February 12th](https://discourse.julialang.org/t/1-11-feature-freeze-february-12th/109759)

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**Author:** [@kristoffer.carlsson](https://discourse.julialang.org/u/kristoffer.carlsson)\
**Replies:** 1\
**Last updated:** [February 16, 2024, 9:22am UTC](https://discourse.julialang.org/t/1-11-feature-freeze-february-12th/109759 "2024-02-16T09:22:19Z")

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Heads up: this is to let people know that if they have any PRs that they really want to get into Julia 1.11, the feature freeze for the 1.11 release will be on Monday, February 12th. There is some leeway with PRs that h…

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## [Julia never stops compiling for new recursive Vector types](https://discourse.julialang.org/t/julia-never-stops-compiling-for-new-recursive-vector-types/110232)

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**Author:** [@mnemnion](https://discourse.julialang.org/u/mnemnion)\
**Replies:** 18\
**Last updated:** [February 15, 2024, 8:21pm UTC](https://discourse.julialang.org/t/julia-never-stops-compiling-for-new-recursive-vector-types/110232 "2024-02-15T20:21:54Z")

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This is… unexpected behavior. I feel like inference should give up at some point. julia\> w = \[1\]; @time for i = 1:100 global w = \[w\] end 0.227547 seconds (466.23 k allocations: 31.348 MiB, 1.52% gc tim…

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## [.. broadcast object property](https://discourse.julialang.org/t/broadcast-object-property/47104)

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**Author:** [@Lincoln\_Hannah](https://discourse.julialang.org/u/Lincoln_Hannah)\
**Replies:** 41\
**Last updated:** [February 15, 2024, 8:21am UTC](https://discourse.julialang.org/t/broadcast-object-property/47104 "2024-02-15T08:21:52Z")

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A few years back I requested … be used to broadcast object property over array of objects. If A.x is property x of object A. Then Array\_of\_A…x is an array of the x properties of the A objects. Was told … was al…

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## [Narrowing typed globals](https://discourse.julialang.org/t/narrowing-typed-globals/110177)

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**Author:** [@Dan](https://discourse.julialang.org/u/Dan)\
**Replies:** 1\
**Last updated:** [February 13, 2024, 11:06pm UTC](https://discourse.julialang.org/t/narrowing-typed-globals/110177 "2024-02-13T23:06:33Z")

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When locking a non-concrete type to a global, it may be reasonable to allow narrowing the locked type to a subtype. Consider: julia\> s::Number = 3 3 julia\> s::Int64 = 5 ERROR: cannot set type for global Main.s. It alr…

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## [What are the pros and cons of row/column major ordering?](https://discourse.julialang.org/t/what-are-the-pros-and-cons-of-row-column-major-ordering/110045)

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**Author:** [@leespen1](https://discourse.julialang.org/u/leespen1)\
**Replies:** 10\
**Last updated:** [February 13, 2024, 4:53pm UTC](https://discourse.julialang.org/t/what-are-the-pros-and-cons-of-row-column-major-ordering/110045 "2024-02-13T16:53:10Z")

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I understand that because matrices in Julia are stored in column major order, it is best to iterate over them in column major order. What is less clear to me is why one would want to store matrices in column major order…

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## [Internals of types and how they hash](https://discourse.julialang.org/t/internals-of-types-and-how-they-hash/109998)

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**Author:** [@mnemnion](https://discourse.julialang.org/u/mnemnion)\
**Replies:** 10\
**Last updated:** [February 9, 2024, 8:30pm UTC](https://discourse.julialang.org/t/internals-of-types-and-how-they-hash/109998 "2024-02-09T20:30:05Z")

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Yes, that makes a lot more sense, occurred to me that one could just do that after I posted. I presume that Base.hash(T::DataType, h) uses the immutable parts of the DataType struct? It would kind of have to. That woul…

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## [Pkg.jl: Splitting the default environment in two](https://discourse.julialang.org/t/pkg-jl-splitting-the-default-environment-in-two/109950)

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**Author:** [@jar1](https://discourse.julialang.org/u/jar1)\
**Replies:** 1\
**Last updated:** [February 8, 2024, 8:41pm UTC](https://discourse.julialang.org/t/pkg-jl-splitting-the-default-environment-in-two/109950 "2024-02-08T20:41:07Z")

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It’s useful to have an environment that’s inherited, for things like Revise.jl and OhMyREPL.jl. It’s also useful to have an environment that’s activated by default when running julia, for quick interactive sessions. Cur…

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## [Memory aliasing rules and reinterpret](https://discourse.julialang.org/t/memory-aliasing-rules-and-reinterpret/109875)

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**Author:** [@foobar\_lv2](https://discourse.julialang.org/u/foobar_lv2)\
**Replies:** 8\
**Last updated:** [February 7, 2024, 9:22pm UTC](https://discourse.julialang.org/t/memory-aliasing-rules-and-reinterpret/109875 "2024-02-07T21:22:14Z")

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I wanted to ask about the julia aliasing rules for memory accesses. Unfortunately, the docs are not super clear about that, e.g. Julia currently uses LLVM’s Type Based Alias Analysis. To find the comments that documen…

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## [Left and right division for strings](https://discourse.julialang.org/t/left-and-right-division-for-strings/109839)

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**Author:** [@jar1](https://discourse.julialang.org/u/jar1)\
**Replies:** 25\
**Last updated:** [February 7, 2024, 8:32pm UTC](https://discourse.julialang.org/t/left-and-right-division-for-strings/109839 "2024-02-07T20:32:03Z")

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For numbers and matrices, we have x \* y / y == x and x \\ (x \* y) == y. Since we have \* for strings, we could implement / and \\ for strings too: "abcd" / "cd" == "ab" "ab" \\ "abcd" == "cd" AFAICT, it would be algebraic…

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## [How can we maintain easy generics in the face of demand for a “safe” language?](https://discourse.julialang.org/t/how-can-we-maintain-easy-generics-in-the-face-of-demand-for-a-safe-language/109734)

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**Author:** [@Tarny\_GG\_Channie](https://discourse.julialang.org/u/Tarny_GG_Channie)\
**Replies:** 25\
**Last updated:** [February 7, 2024, 6:01pm UTC](https://discourse.julialang.org/t/how-can-we-maintain-easy-generics-in-the-face-of-demand-for-a-safe-language/109734 "2024-02-07T18:01:05Z")

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Julia is moving in the direction of having a static sub-language and even things like enforceable interface/etc. However, if we are not VERY careful, we can lose one big advantage that Julia has, easy generic. Duck typi…

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