# General Usage

**URL:** https://discourse.julialang.org/c/usage/6.md

[Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md)

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## [About the General Usage category](https://discourse.julialang.org/t/about-the-general-usage-category/14)

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**Author:** [@system](https://discourse.julialang.org/u/system)\
**Replies:** 0\
**Last updated:** [October 19, 2016, 3:04am UTC](https://discourse.julialang.org/t/about-the-general-usage-category/14 "2016-10-19T03:04:45Z")

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Questions and discussions about using Julia and its packages. The Performance subcategory can be used for dedicated discussions about maximizing speed. Be civil and respectful – read the community standards Before as…

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## [How to return a macro from a macro?](https://discourse.julialang.org/t/how-to-return-a-macro-from-a-macro/139612)

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**Author:** [@ysaak](https://discourse.julialang.org/u/ysaak)\
**Replies:** 5\
**Last updated:** [September 22, 2026, 10:06pm UTC](https://discourse.julialang.org/t/how-to-return-a-macro-from-a-macro/139612 "2026-09-22T22:06:11Z")

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I want to create a macro that receives the header foo(args) and body begin ... end and returns a macro version of it. macro macwo(header::Expr, body::Expr) #= macro header body end =# end # Impl…

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## [Cannot download general registry due to a corporate antivirus](https://discourse.julialang.org/t/cannot-download-general-registry-due-to-a-corporate-antivirus/139605)

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**Author:** [@LaurentPlagne](https://discourse.julialang.org/u/LaurentPlagne)\
**Replies:** 7\
**Last updated:** [September 22, 2026, 8:06pm UTC](https://discourse.julialang.org/t/cannot-download-general-registry-due-to-a-corporate-antivirus/139605 "2026-09-22T20:06:43Z")

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A change in my corporate antivirus cause problem when I try to install new packages. I tried to change JULIA\_PKG\_DOWNLOAD\_TIMEOUT and Curl.CURLOPT\_LOW\_SPEED limits but it seems to have no effect: julia\> ENV\["JULIA\_PKG\_…

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## [Juliaup gui?](https://discourse.julialang.org/t/juliaup-gui/139463)

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**Author:** [@jdad](https://discourse.julialang.org/u/jdad)\
**Replies:** 35\
**Last updated:** [September 21, 2026, 8:25pm UTC](https://discourse.julialang.org/t/juliaup-gui/139463 "2026-09-21T20:25:56Z")

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I saw that with 1,13 release, Juliaup was coming with a GUI. And when I take a look, this is documented in Juliaup GitHub. However, I am using Juliaup 1.22.3 and selfupdate stay on this version. Then no gui is found. Wh…

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## [Can I make stack overflow warnings fatal?](https://discourse.julialang.org/t/can-i-make-stack-overflow-warnings-fatal/139579)

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**Author:** [@piechologist](https://discourse.julialang.org/u/piechologist)\
**Replies:** 4\
**Last updated:** [September 21, 2026, 4:01pm UTC](https://discourse.julialang.org/t/can-i-make-stack-overflow-warnings-fatal/139579 "2026-09-21T16:01:15Z")

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I saw my Julia process writing Warning: detected a stack overflow; program state may be corrupted, so further execution might be unreliable. to stderr after failed C-calls. The process is running as a systemd unit. Curre…

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## [Constraint structs with automatic parameter handlings?](https://discourse.julialang.org/t/constraint-structs-with-automatic-parameter-handlings/139568)

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**Author:** [@lrnv](https://discourse.julialang.org/u/lrnv)\
**Replies:** 14\
**Last updated:** [September 21, 2026, 11:43am UTC](https://discourse.julialang.org/t/constraint-structs-with-automatic-parameter-handlings/139568 "2026-09-21T11:43:27Z")

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Hey, I’m looking around to see if there is somewhere in the ecosystem a package that would allow me to define structs with arbitrary constraints in them, through something like @probably\_a\_macro struct MyStruct{T} …

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## [How to avoid multiple \_\_init\_\_ calls?](https://discourse.julialang.org/t/how-to-avoid-multiple-init-calls/139531)

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**Author:** [@Alex1](https://discourse.julialang.org/u/Alex1)\
**Replies:** 5\
**Last updated:** [September 18, 2026, 11:54pm UTC](https://discourse.julialang.org/t/how-to-avoid-multiple-init-calls/139531 "2026-09-18T23:54:07Z")

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I use project wide config used by many modules. And sometimes I observe its \_\_init\_\_ function called many times, I assume during compilation. How to avoid that is the proper way to use ccall(:jl\_generating\_output, Cint,…

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## [Exploring 24/7 Market Data with Julia: Volatility and Simple Visualizations](https://discourse.julialang.org/t/exploring-24-7-market-data-with-julia-volatility-and-simple-visualizations/139537)

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**Author:** [@Raducanu\_Loisy](https://discourse.julialang.org/u/Raducanu_Loisy)\
**Replies:** 5\
**Last updated:** [September 18, 2026, 11:28pm UTC](https://discourse.julialang.org/t/exploring-24-7-market-data-with-julia-volatility-and-simple-visualizations/139537 "2026-09-18T23:28:12Z")

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Recently, I’ve been experimenting with Julia for analyzing 24/7 market data. I normally work with more general data tools, so this was partly an excuse to see how comfortable Julia feels for a small time-series project. …

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## [Confusing package incompatibility between HTTP, GeoStats and CairoMakie?](https://discourse.julialang.org/t/confusing-package-incompatibility-between-http-geostats-and-cairomakie/139085)

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**Author:** [@TimG](https://discourse.julialang.org/u/TimG)\
**Replies:** 5\
**Last updated:** [September 18, 2026, 12:06pm UTC](https://discourse.julialang.org/t/confusing-package-incompatibility-between-http-geostats-and-cairomakie/139085 "2026-09-18T12:06:43Z")

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I created a new environment, activated it and then added, in this order, CairoMakie, GeoIO, GeoStats, CSV, DataFrames, Dates, HTTP and XLSX. (OW 2027) pkg\> st Status \`C:\\Users\\TGebbels\\...\\Documents\\Open Week\\OW 2027\\Pr…

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## [Seeking input (and creating output) about visualization software](https://discourse.julialang.org/t/seeking-input-and-creating-output-about-visualization-software/139490)

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**Author:** [@BananaMaster3](https://discourse.julialang.org/u/BananaMaster3)\
**Replies:** 2\
**Last updated:** [September 17, 2026, 5:54pm UTC](https://discourse.julialang.org/t/seeking-input-and-creating-output-about-visualization-software/139490 "2026-09-17T17:54:13Z")

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Manifesto I’ve been using Julia for about a year and a half now, and I truly love the language. More specifically, the REPL environment and the general customizability that the language provides are both amazing, especia…

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## [Implementing HDF5.jl REPL tab completion, private REPL.REPLCompletions.find\_dict\_matches](https://discourse.julialang.org/t/implementing-hdf5-jl-repl-tab-completion-private-repl-replcompletions-find-dict-matches/139505)

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**Author:** [@mkitti](https://discourse.julialang.org/u/mkitti)\
**Replies:** 1\
**Last updated:** [September 17, 2026, 2:57pm UTC](https://discourse.julialang.org/t/implementing-hdf5-jl-repl-tab-completion-private-repl-replcompletions-find-dict-matches/139505 "2026-09-17T14:57:36Z")

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I am implementing multi-level REPL path completion in HDF5.jl. The only way I have figured out how to implement multi-level completion is by overloading REPL.REPLCompletions.find\_dict\_matches which is not public. This AP…

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## [A plot of dynamic dispatch cost](https://discourse.julialang.org/t/a-plot-of-dynamic-dispatch-cost/139517)

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**Author:** [@skraemer](https://discourse.julialang.org/u/skraemer)\
**Replies:** 0\
**Last updated:** [September 17, 2026, 2:53pm UTC](https://discourse.julialang.org/t/a-plot-of-dynamic-dispatch-cost/139517 "2026-09-17T14:53:20Z")

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I made some experiments that helped me further understand both qualitative and quantitative behaviour of dynamic dispatch cost and method caches. So I thought I may as well add it to the collection. Have a look if you li…

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## [Pluto fails to precompile on v1.13](https://discourse.julialang.org/t/pluto-fails-to-precompile-on-v1-13/139450)

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**Author:** [@lazylavenders](https://discourse.julialang.org/u/lazylavenders)\
**Replies:** 13\
**Last updated:** [September 16, 2026, 11:16am UTC](https://discourse.julialang.org/t/pluto-fails-to-precompile-on-v1-13/139450 "2026-09-16T11:16:25Z")

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I recently upgraded to Julia v1.13 and was pleasantly surprised by how quickly packages downloaded. However, Pluto fails to precompile on my machine, which didn’t used to happen on v1.12.7. It appeared that someone else …

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## [In Julia, how can I export a Tiddler (created for TiddlyHost) as a JSON file?](https://discourse.julialang.org/t/in-julia-how-can-i-export-a-tiddler-created-for-tiddlyhost-as-a-json-file/139435)

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**Author:** [@haroldnick0](https://discourse.julialang.org/u/haroldnick0)\
**Replies:** 2\
**Last updated:** [September 15, 2026, 4:43am UTC](https://discourse.julialang.org/t/in-julia-how-can-i-export-a-tiddler-created-for-tiddlyhost-as-a-json-file/139435 "2026-09-15T04:43:40Z")

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In Julia, how can I export a Tiddler (created for TiddlyHost) as a JSON file?

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## [ReTestItems.jl status and Julia 1.13+ compatibility](https://discourse.julialang.org/t/retestitems-jl-status-and-julia-1-13-compatibility/139364)

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**Author:** [@Rafael\_Brus](https://discourse.julialang.org/u/Rafael_Brus)\
**Replies:** 3\
**Last updated:** [September 14, 2026, 4:26pm UTC](https://discourse.julialang.org/t/retestitems-jl-status-and-julia-1-13-compatibility/139364 "2026-09-14T16:26:28Z")

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Hi everyone, Is anyone currently using ReTestItems.jl? I think it is an amazing tool — the parallel test execution and test items workflow have been great for our test suites. However, it currently fails on Julia 1.13…

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## [PerfChecker.jl is reaching a good state and we're looking for ~~labrats~~ testers/users](https://discourse.julialang.org/t/perfchecker-jl-is-reaching-a-good-state-and-were-looking-for-labrats-testers-users/114897)

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**Author:** [@Azzaare](https://discourse.julialang.org/u/Azzaare)\
**Replies:** 1\
**Last updated:** [September 14, 2026, 5:16am UTC](https://discourse.julialang.org/t/perfchecker-jl-is-reaching-a-good-state-and-were-looking-for-labrats-testers-users/114897 "2026-09-14T05:16:01Z")

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Hi there! Years ago, I announced a proof of concept package to handle testing performances over versions: PerfChecker.jl We’re reaching the point were the package is ready to be used (v"0.2.0" waiting for merge). And w…

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## [How to enable REPL Syntax Highlighting in 1.13?](https://discourse.julialang.org/t/how-to-enable-repl-syntax-highlighting-in-1-13/139340)

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**Author:** [@Nathan\_Boyer](https://discourse.julialang.org/u/Nathan_Boyer)\
**Replies:** 20\
**Last updated:** [September 13, 2026, 4:25pm UTC](https://discourse.julialang.org/t/how-to-enable-repl-syntax-highlighting-in-1-13/139340 "2026-09-13T16:25:18Z")

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Julia 1.13 News.md says: " The REPL now provides syntax highlighting for input as you type. See the REPL docs for more info about customization." Julia 1.13 REPL doc says: “The REPL provides syntax highlighting for…

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## [Building a system image using Julia 1.13 fails on Windows](https://discourse.julialang.org/t/building-a-system-image-using-julia-1-13-fails-on-windows/139436)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 0\
**Last updated:** [September 13, 2026, 9:18am UTC](https://discourse.julialang.org/t/building-a-system-image-using-julia-1-13-fails-on-windows/139436 "2026-09-13T09:18:24Z")

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Building a system image on Windows 10 fails if I use Julia 1.13, it succeeds using Julia 1.12. On Julia 1.12 it needs about 34 GB RAM (RAM+pagefile) and 30 minutes. On Julia 1.13 it fails even with 54 GB RAM after 1h:2…

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## [SimpleDirectMediaLayer won't precompile on wayland](https://discourse.julialang.org/t/simpledirectmedialayer-wont-precompile-on-wayland/139414)

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**Author:** [@BananaMaster3](https://discourse.julialang.org/u/BananaMaster3)\
**Replies:** 0\
**Last updated:** [September 12, 2026, 8:22pm UTC](https://discourse.julialang.org/t/simpledirectmedialayer-wont-precompile-on-wayland/139414 "2026-09-12T20:22:43Z")

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Hey all. When I try to add SimpleDirectMediaLayer to my wayland machine, it gives this ridiculously long error. I’m clueless in this area, so I figured I would paste the entire error. I’d appreciate anything on how to d…

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## [Using Juliaup on NixOS (2025 edition)](https://discourse.julialang.org/t/using-juliaup-on-nixos-2025-edition/130250)

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**Author:** [@dlakelan](https://discourse.julialang.org/u/dlakelan)\
**Replies:** 3\
**Last updated:** [September 12, 2026, 7:28pm UTC](https://discourse.julialang.org/t/using-juliaup-on-nixos-2025-edition/130250 "2026-09-12T19:28:43Z")

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Hey Julia friends. I’ve been trying to figure this out this morning in response to a student who is using NixOS and has convinced me to give it a try. In general on NixOS nothing is in the filesystem where things expect …

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## [Build a jll library locally with BinaryBuilder](https://discourse.julialang.org/t/build-a-jll-library-locally-with-binarybuilder/92997)

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**Author:** [@gitboy16](https://discourse.julialang.org/u/gitboy16)\
**Replies:** 1\
**Last updated:** [September 12, 2026, 5:45pm UTC](https://discourse.julialang.org/t/build-a-jll-library-locally-with-binarybuilder/92997 "2026-09-12T17:45:02Z")

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Hi, Is there a way to build a jll package from a c++ library locally on a computer using BinaryBuilder.jl? If yes, is there an example of how it can be done on windows? For example for do you build libCurl locally on a…

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## [What might be holding up a \_jll update?](https://discourse.julialang.org/t/what-might-be-holding-up-a-jll-update/139338)

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**Author:** [@joa-quim](https://discourse.julialang.org/u/joa-quim)\
**Replies:** 8\
**Last updated:** [September 12, 2026, 10:19am UTC](https://discourse.julialang.org/t/what-might-be-holding-up-a-jll-update/139338 "2026-09-12T10:19:01Z")

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Hi, In GMT.jl the GMT\_jll version is been hold by something to a version one year old. If I force the install with \] add GMT\_jll I see (checked in 3 different computers) st ... \[b68b8c3f\] GMT\_jll v6.6.0+0 but newest …

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## [Symbolics Equality](https://discourse.julialang.org/t/symbolics-equality/102803)

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**Author:** [@Allan\_Baker](https://discourse.julialang.org/u/Allan_Baker)\
**Replies:** 9\
**Last updated:** [September 12, 2026, 9:16am UTC](https://discourse.julialang.org/t/symbolics-equality/102803 "2026-09-12T09:16:21Z")

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I’m trying to extend some modules to work with Symbolics by getting rid of Bool conditionals and divide by zero checks etc. I’m trying to add some unit tests and I want to test if two symbolic equations are equivalent. …

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## [FlexUnits |\> Simplify: extended capability suggestion](https://discourse.julialang.org/t/flexunits-simplify-extended-capability-suggestion/139367)

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**Author:** [@Jake](https://discourse.julialang.org/u/Jake)\
**Replies:** 4\
**Last updated:** [September 11, 2026, 6:04pm UTC](https://discourse.julialang.org/t/flexunits-simplify-extended-capability-suggestion/139367 "2026-09-11T18:04:59Z")

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A bit of background, I first started using MathCad around 1993. This was the way I became familiar with units aware calculation software. A big step up from spreadsheets! Let me walk you through an example. Here := i…

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## [Packages for colored REPL output?](https://discourse.julialang.org/t/packages-for-colored-repl-output/132925)

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**Author:** [@Nathan\_Boyer](https://discourse.julialang.org/u/Nathan_Boyer)\
**Replies:** 1\
**Last updated:** [September 11, 2026, 2:22pm UTC](https://discourse.julialang.org/t/packages-for-colored-repl-output/132925 "2026-09-11T14:22:52Z")

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I use OhMyREPL.jl for colored input, but it doesn’t do any coloring of the output. I am consistently missing the “e” in my calculation outputs (e.g. 5.105088062083414e6) since I only care about 3-5 significant digits and…

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## [Package installation includes unnecessary docs files](https://discourse.julialang.org/t/package-installation-includes-unnecessary-docs-files/139342)

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**Author:** [@arnaud-ma](https://discourse.julialang.org/u/arnaud-ma)\
**Replies:** 3\
**Last updated:** [September 11, 2026, 7:06am UTC](https://discourse.julialang.org/t/package-installation-includes-unnecessary-docs-files/139342 "2026-09-11T07:06:37Z")

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I just installed Extremes.jl (Julia 1.13.0) and the size of ~/.julia/package/Extremes is 120Mio just because of the docs folder which contains big files (useless to me). I don’t really plan to use this package but this…

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## [What is the current best practice to fix a broken package install?](https://discourse.julialang.org/t/what-is-the-current-best-practice-to-fix-a-broken-package-install/139320)

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**Author:** [@Benny](https://discourse.julialang.org/u/Benny)\
**Replies:** 5\
**Last updated:** [September 10, 2026, 8:47pm UTC](https://discourse.julialang.org/t/what-is-the-current-best-practice-to-fix-a-broken-package-install/139320 "2026-09-10T20:47:38Z")

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Haven’t run into this personally yet, but it’s been on my mind. Say Package@v1.2.3 is not working properly in a given environment, but I do not know why and want to reinstall it and its dependencies in case a file got co…

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## [Idiomatic Julia code in AI generated code](https://discourse.julialang.org/t/idiomatic-julia-code-in-ai-generated-code/139183)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 20\
**Last updated:** [September 10, 2026, 6:36pm UTC](https://discourse.julialang.org/t/idiomatic-julia-code-in-ai-generated-code/139183 "2026-09-10T18:36:22Z")

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I find AI coding tools such as Claude Code incredibly useful, especially when combined with tools like Kaimon.jl. However, I also find that the code they generate is often surprisingly non-idiomatic Julia. Beyond aesthe…

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## [Easier way to replace templates in Franklin.jl?](https://discourse.julialang.org/t/easier-way-to-replace-templates-in-franklin-jl/87322)

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**Author:** [@wsshin](https://discourse.julialang.org/u/wsshin)\
**Replies:** 3\
**Last updated:** [September 10, 2026, 4:21pm UTC](https://discourse.julialang.org/t/easier-way-to-replace-templates-in-franklin-jl/87322 "2026-09-10T16:21:07Z")

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I am trynig to test various templates for my website generated by Franklin.jl. Currently I am doing this by newsite("\<top directory\>", template="\<new template name\>"), but this seems to overwrite the top directory, whic…

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## [Adding the package to its workspaces](https://discourse.julialang.org/t/adding-the-package-to-its-workspaces/139331)

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**Author:** [@Gregstrq](https://discourse.julialang.org/u/Gregstrq)\
**Replies:** 13\
**Last updated:** [September 10, 2026, 2:43pm UTC](https://discourse.julialang.org/t/adding-the-package-to-its-workspaces/139331 "2026-09-10T14:43:44Z")

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I am looking into the workspaces feature, but have trouble understanding what is the correct way to add the package to its workspace einvironment: dev or add. For example, in the Pkg.jl manual, it is suggested to add th…

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