# Is Jeff Bezanson's 2014 "Introduction to Julia Internals" relevant in 2021 onward?

**URL:** <https://discourse.julialang.org/t/is-jeff-bezansons-2014-introduction-to-julia-internals-relevant-in-2021-onward/73255>\
**Category:** Internals & Design\
**Tags:** question\
**Created:** [December 17, 2021, 12:53pm UTC](https://discourse.julialang.org/t/is-jeff-bezansons-2014-introduction-to-julia-internals-relevant-in-2021-onward/73255 "2021-12-17T12:53:44Z")\
**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:** [December 17, 2021, 12:53pm UTC](https://discourse.julialang.org/t/is-jeff-bezansons-2014-introduction-to-julia-internals-relevant-in-2021-onward/73255/1 "2021-12-17T12:53:44Z")

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I’m kind of fan of Jeff Bezanson’s talks and recently I watched his talk from first JuliaCon 2014 titled [_Introduction to Julia Internals_](https://www.youtube.com/watch?v=osdeT-tWjzk). I found there many information that were totally new to me about internal working of the Julia, but since talk is from 2014 many things may or may not change. My knowledge about such things is approximately 0, so I don’t know what part of Julia, or any programming language, is stable and what is in flux.

If most of the talk is still relevant, it is very valuable source of information, since I didn’t find any other talk on YT diving so much into internal working of Julia. In such situation I think it would be good idea for me to watch it again and at timestamps to it. This is small thing, but I can’t do much more.

If is too outdated, is there any other similar source with such information to watch/read? This is probably silly question, but to this moment I didn’t find anything like that. I don’t count Julia documentation, since it now over 1000 pages long and I never read beyond first part of it.

I apologize for all language mistakes. My English is bad and not good.

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**Author:** ![StefanKarpinski](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/stefankarpinski/32/24_2.png) [@StefanKarpinski](https://discourse.julialang.org/u/StefanKarpinski)\
**Post date:** [December 17, 2021, 1:07pm UTC](https://discourse.julialang.org/t/is-jeff-bezansons-2014-introduction-to-julia-internals-relevant-in-2021-onward/73255/2 "2021-12-17T13:07:22Z")

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Still mostly accurate, I suspect. Have you checked out the [dev docs](https://docs.julialang.org/en/v1/devdocs/functions/)?

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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 17, 2021, 2:20pm UTC](https://discourse.julialang.org/t/is-jeff-bezansons-2014-introduction-to-julia-internals-relevant-in-2021-onward/73255/3 "2021-12-17T14:20:57Z")

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Thank you for the answer. In such situation I will watch it and try to make timestamps of it.

> [@StefanKarpinski](#):
>
> Have you checked out the [dev docs](https://docs.julialang.org/en/v1/devdocs/functions/)?

No. As I said, I never dived reasonably dip into documentation.

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<div class="post-metadata">

**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 20, 2021, 11:20pm UTC](https://discourse.julialang.org/t/is-jeff-bezansons-2014-introduction-to-julia-internals-relevant-in-2021-onward/73255/4 "2021-12-20T23:20:49Z")

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I created timestamps for this talk and put them in appropriate GitHub [issue](https://github.com/JuliaCommunity/YouTubeVideoTimestamps/issues/111). Feel free to correct and change everything in them.

00:00 Origin story  
00:28 Aim of the talk  
00:57 Three component of programming language: data model, code model, glue  
03:02 Tag-bits arrangement  
04:34 Type primitives  
05:45 Object graph of types  
06:48 Code object primitives  
07:41 Code intrinsics  
08:15 Translation stages  
10:09 Test subject  
10:17 Julia is just lisp  
12:04 “You can call various functions, that are of curse not documented.”  
14:03 Parsed test subject code  
16:00 Expanding macros  
17:17 Syntax de-sugaring  
18:52 Are |#s number| symbols related to LLVM code?  
19:23 Statementize control flow  
20:18 Flattening code using goto form  
21:47 Flattened code in @code\_lovered form  
22:13 Would it be any worth in reading code in goto form?  
22:53 Why we have in code statements like “6: goto 7”?  
23:45 Running the code  
24:51 Method cache (file gf.c)  
27:23 Overview of type inference  
28:30 Compile-time method lookup and secret internal function  
30:07 Type inference (file inference.jl)  
30:50 Inlining, high-level optimisation  
31:32 LLVM IR generation  
31:42 Code generation key concepts  
32:52 emit\_expr and emit\_function  
35:03 Type translation between Julia and LLVM  
35:35 Q&A: When is the most time spent at runtime?  
36:30 Q&A: Do you plan to extend syntax to add new feature?  
37:24 Q&A: Do LLVM and garbage collector allow static analysis?  
38:52 Q&A: Stack and heap allocation  
39:16 Q&A: Can I press button and get graph of whole architecture?  
39:43 Q&A: Better mechanism for simple unions  
40:17 Q&A: Types lookup and exponential complexity  
40:50 Q&A: How many types Julia look up before giving up?  
42:01 Q&A: How “widening” of types works?  
43:27 Q&A: What are the heuristic that decided that something is inline or not?