# Julia internal works: what everybody need to know?

**URL:** <https://discourse.julialang.org/t/julia-internal-works-what-everybody-need-to-know/17212>\
**Category:** New to Julia\
**Created:** [November 6, 2018, 11:25am UTC](https://discourse.julialang.org/t/julia-internal-works-what-everybody-need-to-know/17212 "2018-11-06T11:25:47Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![KZiemian](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/kziemian/32/9020_2.png) [@KZiemian](https://discourse.julialang.org/u/KZiemian)\
**Post date:** [November 6, 2018, 11:25am UTC](https://discourse.julialang.org/t/julia-internal-works-what-everybody-need-to-know/17212/1 "2018-11-06T11:25:47Z")

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When I writing simple presentation on Julia, it appears to me, that I know very little about it internal working and I probably won’t be able to answer most question about it. Like probably most important question: why time for (first) adding 1 + 1 can be so long?

Is any article/discussion “What every Julia user should know about internals” out there? I don’t find it.

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**Author:** ![Tamas\_Papp](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tamas_papp/32/25949_2.png) [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Post date:** [November 6, 2018, 11:31am UTC](https://discourse.julialang.org/t/julia-internal-works-what-everybody-need-to-know/17212/2 "2018-11-06T11:31:09Z")

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In a nutshell, the functions are compiled for their argument types as needed.

A longer discussion is eg

[![](https://global.discourse-cdn.com/julialang/original/3X/9/c/9c7dcad2631cec7ff3a22f67682c60b013a07c63.jpeg "JuliaCon 2017 | AoT or JIT: How Does Julia Work? | Jameson Nash") ](https://www.youtube.com/watch?v=7KGZ_9D_DbI&t=5s)

`+(1, 1)` is probably not a good example of this though, as that should be compiler by the time you get to a REPL.

> [@KZiemian](#):
>
> I know very little about it internal working and I probably won’t be able to answer most question about it.

I think this is fine. Just don’t go into details about it then. Compilation times have improved a lot and keep improving.

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**Author:** ![mohamed82008](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mohamed82008/32/18171_2.png) [@mohamed82008](https://discourse.julialang.org/u/mohamed82008)\
**Post date:** [November 6, 2018, 2:05pm UTC](https://discourse.julialang.org/t/julia-internal-works-what-everybody-need-to-know/17212/3 "2018-11-06T14:05:20Z")

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You may find the links in this thread useful [Docs on parse-time, compile-time and run-time operations?](https://discourse.julialang.org/t/docs-on-parse-time-compile-time-and-run-time-operations/4955) I know I did 🙂

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**Author:** ![KZiemian](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/kziemian/32/9020_2.png) [@KZiemian](https://discourse.julialang.org/u/KZiemian)\
**Post date:** [December 5, 2018, 8:44pm UTC](https://discourse.julialang.org/t/julia-internal-works-what-everybody-need-to-know/17212/4 "2018-12-05T20:44:02Z")

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Information of my talk was on the page for one day, when colleague ask me on corridor about Julia and if it is compiled or interpreted. This video was very helpfully, even as I don’t understand most of it, this is to  
advanced computer science for my knowledge. But knowledge of your ignorance is very important knowledge.

Thank you for help.