# General Usage

**URL:** https://discourse.julialang.org/c/usage/6.md?page=19

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**Page:** 20

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## [Extract unique types between two Tuples at compile time](https://discourse.julialang.org/t/extract-unique-types-between-two-tuples-at-compile-time/135476)

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**Author:** [@albertomercurio](https://discourse.julialang.org/u/albertomercurio)\
**Replies:** 10\
**Last updated:** [February 9, 2026, 7:20pm UTC](https://discourse.julialang.org/t/extract-unique-types-between-two-tuples-at-compile-time/135476 "2026-02-09T19:20:56Z")

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Hello, I have two Tuples x and y containing objects of different types. I now want to create at compile time a list containing only the unique types. I have tried this function test2(x::T1, y::T2) where {T1 \<: Tuple, T…

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## [How to avoid runtime-dispatch in loop](https://discourse.julialang.org/t/how-to-avoid-runtime-dispatch-in-loop/135517)

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**Author:** [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)\
**Replies:** 7\
**Last updated:** [February 9, 2026, 6:22pm UTC](https://discourse.julialang.org/t/how-to-avoid-runtime-dispatch-in-loop/135517 "2026-02-09T18:22:59Z")

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If i have a vector of different objects it is inherently an abstract type. How can I still avoid runtime-dispatch when looping over it? abstract type AbstractFoo end mutable struct Foo1 \<: AbstractFoo k::Float64 end m…

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## [PackageCompiler.jl: What is it doing and how do I use it correctly?](https://discourse.julialang.org/t/packagecompiler-jl-what-is-it-doing-and-how-do-i-use-it-correctly/135530)

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**Author:** [@abraemer](https://discourse.julialang.org/u/abraemer)\
**Replies:** 3\
**Last updated:** [February 8, 2026, 5:51pm UTC](https://discourse.julialang.org/t/packagecompiler-jl-what-is-it-doing-and-how-do-i-use-it-correctly/135530 "2026-02-08T17:51:11Z")

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Today I was playing with PackageCompiler.jl (PC) because I am wondering whether it could play a role in reducing startup times (sparked by the recent discussions about the worsening of Julia startup times ref). During m…

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## [I think a bug in Symbolics package, but not sure](https://discourse.julialang.org/t/i-think-a-bug-in-symbolics-package-but-not-sure/135521)

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**Author:** [@ejolson](https://discourse.julialang.org/u/ejolson)\
**Replies:** 2\
**Last updated:** [February 7, 2026, 9:55am UTC](https://discourse.julialang.org/t/i-think-a-bug-in-symbolics-package-but-not-sure/135521 "2026-02-07T09:55:29Z")

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I try the code using Symbolics D(f,x)=expand\_derivatives(Differential(x)(f)) @variables H,S,r1 K1=10000.0; K2=6000.0; a1=0.5; a2=0.5; r2=0.25; dHdt(H,S)=r1\*H\*(1-(a1\*S+H)/K1) dSdt(H,S)=r2\*S\*(1-(S+a2\*H)/K2) f(H,S)=dHdt(H,…

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## [Could not resolve this error: "ERROR: expected package \`DyadInterface \[99806f68\]\` to be registered"](https://discourse.julialang.org/t/could-not-resolve-this-error-error-expected-package-dyadinterface-99806f68-to-be-registered/135519)

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**Author:** [@pandeysudan27](https://discourse.julialang.org/u/pandeysudan27)\
**Replies:** 1\
**Last updated:** [February 7, 2026, 1:44am UTC](https://discourse.julialang.org/t/could-not-resolve-this-error-error-expected-package-dyadinterface-99806f68-to-be-registered/135519 "2026-02-07T01:44:14Z")

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I am following Dyad tutorial from Getting Started with Dyad Studio | Dyad I am getting the following error. while running the \] test . Any solution? Error Updating registry at \`C:\\Users\\Firstname Lastname\\.julia\\regist…

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## [Shift+Enter shortcut behaving oddly](https://discourse.julialang.org/t/shift-enter-shortcut-behaving-oddly/135489)

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**Author:** [@bebentinho](https://discourse.julialang.org/u/bebentinho)\
**Replies:** 4\
**Last updated:** [February 6, 2026, 7:09pm UTC](https://discourse.julialang.org/t/shift-enter-shortcut-behaving-oddly/135489 "2026-02-06T19:09:43Z")

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My “Shift+Enter” shortcut is behaving oddly on VS Code after a code I was running crashed. Previously, it ran the specific line (or for, function, if blocks, etc…) selected and moved to the next one, but now it tries to …

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## [Efficient custom broadcasting challenge](https://discourse.julialang.org/t/efficient-custom-broadcasting-challenge/135511)

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**Author:** [@Deduction42](https://discourse.julialang.org/u/Deduction42)\
**Replies:** 2\
**Last updated:** [February 6, 2026, 6:14pm UTC](https://discourse.julialang.org/t/efficient-custom-broadcasting-challenge/135511 "2026-02-06T18:14:56Z")

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I am trying to build some optimized broadcasting behavior for some factorized arrays of quantities for FlexUnits.jl. It turns out that if a matrix of quantities can be multiplied by vector of quantities, the matrix units…

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## [Getting beta2 from juliaup](https://discourse.julialang.org/t/getting-beta2-from-juliaup/135490)

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**Author:** [@Paul\_Soderlind](https://discourse.julialang.org/u/Paul_Soderlind)\
**Replies:** 2\
**Last updated:** [February 6, 2026, 6:02pm UTC](https://discourse.julialang.org/t/getting-beta2-from-juliaup/135490 "2026-02-06T18:02:12Z")

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…takes the following steps juliaup update (to actually get beta2 listed) juliaup add beta That step 1 was required surprised me. Even more strange, this was required on one of my windows computers, not on the other.

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## [Wiener Process Sampling](https://discourse.julialang.org/t/wiener-process-sampling/135498)

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**Author:** [@diffeqslvr](https://discourse.julialang.org/u/diffeqslvr)\
**Replies:** 2\
**Last updated:** [February 6, 2026, 3:06pm UTC](https://discourse.julialang.org/t/wiener-process-sampling/135498 "2026-02-06T15:06:09Z")

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As a sanity check, I try to simulate a pure Wiener process du = D dW. However, when I plot the variable, it does not look like a random walk; rather, the curves follows line segments: Is that because I am doing somet…

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## [Does @propagate\_inbounds affect one method, or all methods (-\> the function)?](https://discourse.julialang.org/t/does-propagate-inbounds-affect-one-method-or-all-methods-the-function/135461)

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**Author:** [@marteaua](https://discourse.julialang.org/u/marteaua)\
**Replies:** 3\
**Last updated:** [February 6, 2026, 11:24am UTC](https://discourse.julialang.org/t/does-propagate-inbounds-affect-one-method-or-all-methods-the-function/135461 "2026-02-06T11:24:45Z")

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The Base.@propagate\_inbounds documentation says the macro affects the annotated “function”. Does it mean that it affects all the method defined to a specific function ? Or just the annotated method? I ask because I wan…

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## [When my REPL input fills the line, previously displayed lines get "eaten"](https://discourse.julialang.org/t/when-my-repl-input-fills-the-line-previously-displayed-lines-get-eaten/135361)

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**Author:** [@qua4tre](https://discourse.julialang.org/u/qua4tre)\
**Replies:** 4\
**Last updated:** [February 5, 2026, 7:32pm UTC](https://discourse.julialang.org/t/when-my-repl-input-fills-the-line-previously-displayed-lines-get-eaten/135361 "2026-02-05T19:32:27Z")

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Say I am working at the REPL, and I have a few inputs and outputs displayed: julia\> 2 + 2 4 julia\> exp(6) 403.4287934927351 julia\> Next I have a really long input line that exactly fills the width of my terminal: ju…

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## [Circular dependencies detected](https://discourse.julialang.org/t/circular-dependencies-detected/135481)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 3\
**Last updated:** [February 5, 2026, 5:44pm UTC](https://discourse.julialang.org/t/circular-dependencies-detected/135481 "2026-02-05T17:44:12Z")

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I am getting this warning: ┌ Warning: Circular dependency detected. │ Precompilation will be skipped for dependencies in this cycle: │ ┌ Symbolics → SymbolicsPreallocationToolsExt │ └─ Symbolics → SymbolicsForwardDiff…

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## [Juliac using packages](https://discourse.julialang.org/t/juliac-using-packages/135103)

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**Author:** [@Thomas008](https://discourse.julialang.org/u/Thomas008)\
**Replies:** 15\
**Last updated:** [February 5, 2026, 4:06pm UTC](https://discourse.julialang.org/t/juliac-using-packages/135103 "2026-02-05T16:06:53Z")

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I use juliac to generate small binaries from julia code. It is a great tool. There are unfortunately only few packages that can be applied when using juliac (e.g. DataStructures.). Applying other useful packages (e.g. …

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## [How to update QML properties from Julia in QML.jl (Signal-like pattern?)](https://discourse.julialang.org/t/how-to-update-qml-properties-from-julia-in-qml-jl-signal-like-pattern/135185)

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**Author:** [@Rakesh](https://discourse.julialang.org/u/Rakesh)\
**Replies:** 11\
**Last updated:** [February 5, 2026, 12:15pm UTC](https://discourse.julialang.org/t/how-to-update-qml-properties-from-julia-in-qml-jl-signal-like-pattern/135185 "2026-02-05T12:15:47Z")

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I am currently learning QML.jl, IMO matured GUI framework for Julia. It’s documentation is quite limited so I decided that first prototype in PySide6(which has lot of resources) then port the code to Julia. I am current…

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## [Caching in Integrals.jl](https://discourse.julialang.org/t/caching-in-integrals-jl/135443)

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**Author:** [@omerc](https://discourse.julialang.org/u/omerc)\
**Replies:** 4\
**Last updated:** [February 5, 2026, 2:25am UTC](https://discourse.julialang.org/t/caching-in-integrals-jl/135443 "2026-02-05T02:25:25Z")

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Recently, I tried to numerically integrate a function for multiple parameters. The integral is four dimensional, so I use CubatureJLh() (but I don’t mind using other methods - the documentation doesn’t elaborate a lot on…

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## [Libjulia: is it really necessary to wrap immutable variables to protect them and why?](https://discourse.julialang.org/t/libjulia-is-it-really-necessary-to-wrap-immutable-variables-to-protect-them-and-why/135441)

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**Author:** [@gvanuxem](https://discourse.julialang.org/u/gvanuxem)\
**Replies:** 1\
**Last updated:** [February 4, 2026, 9:08pm UTC](https://discourse.julialang.org/t/libjulia-is-it-really-necessary-to-wrap-immutable-variables-to-protect-them-and-why/135441 "2026-02-04T21:08:30Z")

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Hello here, I have a C wrapper that calls Julia functions using libjulia and wraps the result in an IdDict, for example: int64\_t jl\_setindex\_wrap\_eval\_string(int64\_t index, const char\* code) { if (index == 0){ …

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## [Strange type instability in array comprehension](https://discourse.julialang.org/t/strange-type-instability-in-array-comprehension/135456)

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**Author:** [@Maucejo](https://discourse.julialang.org/u/Maucejo)\
**Replies:** 4\
**Last updated:** [February 4, 2026, 9:08pm UTC](https://discourse.julialang.org/t/strange-type-instability-in-array-comprehension/135456 "2026-02-04T21:08:19Z")

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Hi all, I am developing StructuralVibration.jl and I am currently try to eliminate all the type instabilities in the code. While some fixes are obvious. I am facing a type instability that I can’t explain easily. The co…

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## [Revise 3.13 FieldError](https://discourse.julialang.org/t/revise-3-13-fielderror/135451)

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**Author:** [@hendri54](https://discourse.julialang.org/u/hendri54)\
**Replies:** 0\
**Last updated:** [February 4, 2026, 3:24pm UTC](https://discourse.julialang.org/t/revise-3-13-fielderror/135451 "2026-02-04T15:24:48Z")

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Since updating to Julia 1.12 and Revise 3.13 I have been getting errors that look like this: julia\> mdl.check\_comparison(cmp1) ┌ Error: Failed to revise /Users/lutz/Documents/projects/p2022/mismatch/MismatchMM/src/compa…

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## [Is any implementation of sortperm running on multiple threads available?](https://discourse.julialang.org/t/is-any-implementation-of-sortperm-running-on-multiple-threads-available/111853)

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**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 3\
**Last updated:** [February 4, 2026, 2:41pm UTC](https://discourse.julialang.org/t/is-any-implementation-of-sortperm-running-on-multiple-threads-available/111853 "2026-02-04T14:41:03Z")

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As it says: Even experimental code would help. Thanks! Edit: Found this great piece of code: Parallel quicksort openmp - #18 by pitsianis I sort of remembered having seen it, but could not find it again.

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## [REPL completion delay](https://discourse.julialang.org/t/repl-completion-delay/135411)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 12\
**Last updated:** [February 4, 2026, 8:36am UTC](https://discourse.julialang.org/t/repl-completion-delay/135411 "2026-02-04T08:36:19Z")

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I am occasionally observing a slight delay (around 1/2s) in REPL completion (with TAB) in 1.12. Is there any way to debug what is going on under the hood? I am using Revise, but I am not sure if it is called just when I…

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## [Language server put's 1 processor at 100%?](https://discourse.julialang.org/t/language-server-puts-1-processor-at-100/135436)

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**Author:** [@joa-quim](https://discourse.julialang.org/u/joa-quim)\
**Replies:** 2\
**Last updated:** [February 4, 2026, 3:43am UTC](https://discourse.julialang.org/t/language-server-puts-1-processor-at-100/135436 "2026-02-04T03:43:01Z")

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All of the sudden (well, somewhere during this afternoon) when I open either VSC or Atigravity a Julia process is launched that uses one of processor at 100% non stop. Anyone else seeing this? It now stopped, after a 3 …

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## [New Julia versions, higher Pluto loading times](https://discourse.julialang.org/t/new-julia-versions-higher-pluto-loading-times/135187)

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**Author:** [@VivMendes](https://discourse.julialang.org/u/VivMendes)\
**Replies:** 38\
**Last updated:** [February 4, 2026, 12:24am UTC](https://discourse.julialang.org/t/new-julia-versions-higher-pluto-loading-times/135187 "2026-02-04T00:24:27Z")

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I will start teaching two courses (one undergraduate with 350 students and the other a master’s course with 40 students) at the beginning of February. None of those courses involves CS students, which implies that the co…

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## [Create Julia manual offline](https://discourse.julialang.org/t/create-julia-manual-offline/98412)

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**Author:** [@David\_Sagan](https://discourse.julialang.org/u/David_Sagan)\
**Replies:** 8\
**Last updated:** [February 3, 2026, 4:26pm UTC](https://discourse.julialang.org/t/create-julia-manual-offline/98412 "2026-02-03T16:26:47Z")

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I will have a long flight where I will be offline. I would like to setup on my computer (a mac) an image of the Julia manual to look at during the flight. How can I do this? Thanks for any info.

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## [High memory usage when creating lots of temporary C++ objects](https://discourse.julialang.org/t/high-memory-usage-when-creating-lots-of-temporary-c-objects/135399)

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**Author:** [@Vasily\_Pisarev](https://discourse.julialang.org/u/Vasily_Pisarev)\
**Replies:** 9\
**Last updated:** [February 3, 2026, 3:51pm UTC](https://discourse.julialang.org/t/high-memory-usage-when-creating-lots-of-temporary-c-objects/135399 "2026-02-03T15:51:45Z")

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I found out that creating lots of temporary C++ objects through CxxWrap takes a lot of memory (duh!) and does not return that memory to the system after GC. My use case is this package wrapping Voro++ library. Logically…

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## [Is scalar getindex supposed to be allocating](https://discourse.julialang.org/t/is-scalar-getindex-supposed-to-be-allocating/135427)

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**Author:** [@Gregstrq](https://discourse.julialang.org/u/Gregstrq)\
**Replies:** 2\
**Last updated:** [February 3, 2026, 2:30pm UTC](https://discourse.julialang.org/t/is-scalar-getindex-supposed-to-be-allocating/135427 "2026-02-03T14:30:30Z")

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I am a bit stumped by the behavior I have bumped into. I thought that only slicing allocates and scalar indexing should not. But try this thing: a = collect(0.0:1.0:10.0) a\[2\] @allocated a\[2\] For me, it somehow alloca…

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## [There is so much great stuff happening in RISC-V land](https://discourse.julialang.org/t/there-is-so-much-great-stuff-happening-in-risc-v-land/103647)

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**Author:** [@dlakelan](https://discourse.julialang.org/u/dlakelan)\
**Replies:** 39\
**Last updated:** [February 3, 2026, 12:33am UTC](https://discourse.julialang.org/t/there-is-so-much-great-stuff-happening-in-risc-v-land/103647 "2026-02-03T00:33:58Z")

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Like this substantial “microcontroller board” that actually has 64MB of RAM for $9 And this monster server with 64 cores for the price of a typical gaming machine. Debians next release will include RISCV as an archi…

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## [Closures magic and how stable?](https://discourse.julialang.org/t/closures-magic-and-how-stable/135408)

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**Author:** [@mattsignorelli](https://discourse.julialang.org/u/mattsignorelli)\
**Replies:** 7\
**Last updated:** [February 2, 2026, 4:53pm UTC](https://discourse.julialang.org/t/closures-magic-and-how-stable/135408 "2026-02-02T16:53:47Z")

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There is a feature in Julia that has enabled us to do some magical things. It is all thanks to this: julia\> adder(f, a) = ()-\> f() + a adder (generic function with 1 method) julia\> f = ()-\>5 #3 (generic function with 1…

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## [Error when creating my system image with package compiler](https://discourse.julialang.org/t/error-when-creating-my-system-image-with-package-compiler/135409)

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**Author:** [@K5Julien](https://discourse.julialang.org/u/K5Julien)\
**Replies:** 0\
**Last updated:** [February 2, 2026, 2:27pm UTC](https://discourse.julialang.org/t/error-when-creating-my-system-image-with-package-compiler/135409 "2026-02-02T14:27:02Z")

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When I want to create my system image, I get the following error resulting from create\_app, do you have an idea what it means? I don’t understand the error message. julia\> create\_app("MyApp", "mysolver", force=true) Pac…

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## [Invoke for functor methods](https://discourse.julialang.org/t/invoke-for-functor-methods/135397)

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**Author:** [@ettersi](https://discourse.julialang.org/u/ettersi)\
**Replies:** 1\
**Last updated:** [February 2, 2026, 8:20am UTC](https://discourse.julialang.org/t/invoke-for-functor-methods/135397 "2026-02-02T08:20:36Z")

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A minimal example demonstrating the use of invoke() might look something like the following. julia\> abstract type A end struct B \<: A end f(a::A) = "hello world from $a" f(b::B) = invoke(f, Tuple{A}…

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## [How to access a Face defined in faces.toml?](https://discourse.julialang.org/t/how-to-access-a-face-defined-in-faces-toml/135387)

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**Author:** [@matthias314](https://discourse.julialang.org/u/matthias314)\
**Replies:** 0\
**Last updated:** [February 1, 2026, 4:09pm UTC](https://discourse.julialang.org/t/how-to-access-a-face-defined-in-faces-toml/135387 "2026-02-01T16:09:12Z")

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If a define a face myface in my config/faces.toml, say \[myface\] inverse = true then I can apply it to strings via styled"{myface:abc}". But what is the official way to get the face itself as an object of type Face?

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