When I started to learn how to write code years ago I was told "the computer is one of the dumbest machines, it only follows orders even if they are wrong", it really helped me shape my mind to understand the logic of many programs
its not that difficult really. once you build one, its really consistent. its a really fun project tbh. i built an interpter so. which is like a compiler with out the code gen.
@@theowillis6870 that's not really the same as compiling. Also, while it's true that the basics of compiling is easy..... The sheer amount of optimising you have to do to make the compiler even remotely give a decently sized executable file is unreal That's why most people have their language compile into something like LLVM, for example
I remember this quote from the programming classes I took while getting my EE degree. I don't remember who it was attributed to, but... "Computers always do what you tell them to do, and rarely what you want them to do."
Thanks for that amazing quote! Ill share the one I liked: There are 10 types of people in the world, The ones that understand binary and those who don't
When I was teen (15 years ago), I was fascinated in programming. I remember spend a lot of hours on the computer trying to figure out how it works and why a code like "print("Hello world")" works in a machine level, but in that time internet didn't have this kind of videos (in fact, youtube was just beginning). Nowadays with this kind of videos it's really easy learning about everything and I am still fascinated with computer (but now approaching it from neuroscience) and your skills to transmit this information, however are awesome. Thanks a lot !
Even with rhe Internet it's still extrenely difficult to understand, if at all. Processors are insanely complicated nowadays including how they execute instructions
Honestly, the most interesting part was your description of how machine codd works. From the machine code to the output felt always like magic to me, and this starts to give meaning to what is really happening
Me: "Computers work by doing magic." Frame of Essence: "Here's how they actually work." Me: "Computers work by doing 50x more magic than I thought they did."
The Great Zoom no = in programming means "assignment". You assign the value on the right to the variable on the left. Even equations like x = x + 1 are possible. This would not work in mathematics for example, there = is a "comparison". In most programming languages comparison is defined as "==" which is not the same as "="
In Python, you could actually write it in one line as x, y = y, x which is a direct consequence of Python's unpacking. It is fundamentally different from the C-style approach though (as I understand it) because firstly, names in Python don't correspond directly to a location in memory and the y, x on the right is actually a tuple, more explicitly written as (y, x).
Bootstrapping (pull yourself up by your bootstraps / an impossible action) is to compile a compiler from its own source. It's a chicken and egg situation. Which came first? The compiler? Or its self source? The compiler, born from another language. The first C++ compiler originated from C. (Bjarne used C to create a C with Classes preprocessor. He used his C with classes language extension to create Cfront. Cfront compiled his C++ language into C. And that's why C and C++ mix together.) The first C compiler originated from B. (B was first written for the PDP-7 minicomputer. (Programmed Data Processor) It evolved into NB (New B) to support the PDP-11. C was written in NB.) The first B compiler was written in TMG. (TransMoGrifier) The first TMG compiler was written in PDP-7 assembly language. Assembly is machine code made readable. (directly from the opcodes. (operation codes)) Before Assembly, people would've likely used some form of custom assembly code on paper to translate into machine code.
It's not impossible though to write a compiler without using another high level language. Most early compilers and interpreters were written in assembly (for Fortran, Algol, Simula, Lisp, Basic, and so on). Some of them first wrote a simple compiler for a subset of the language in assembly and used it to compile a more advanced compiler (written in that subset, but implementing more of the language).
@@herrbonk3635 of course, but it wouldn't be worth it. the compiler will do the same exact translation you program it to do. the only difference would be how fast those compilers are at doing that. i think we'd take slightly slower compilations, for more well managed and developed compilers. that's the whole reason for higher level languages to begin with. to make development easier and more time efficient. hence why AAA games are written in C/C++, not assembly. we don't need the utmost potential possible out of most stuff. we'd rather have the darn thing finished already. and better compilers means better compiled code.
@@DlcEnergy Hmm, I wasn't discussing efficiency here, but rather principles from an historical perspective. I was under the impression that you did too. However, you somehow seem to miss my point about that interesting middle way between assembly coded and self hosting compilers, using a subset of the HLL implemented. It has been used also for relatively "modern" (at least when you are 50+) languages like Pascal and Modula. I sure agree that compilation speed is much less important today, when everybody has "super computers" (in a very real mening, compared to the situation in the 1960s, or even the early 1990s). I personally love interpreted languages for their great flexiblity and security (checking array accesses, stack overflow, and so on). And my own design of a HLL language happens to be a pretty slow(!) compiler with some aspects of typical interpreters that I find useful. It produces quick and efficient code though. (All statements and their syntax are implemented as fully redefinable operator functions in this language, with pre-, post- or infix syntax, hence its relatively slow parsing speed.)
@@herrbonk3635 That's why i'm bringing efficiency up. Obviously a lower level language can achieve the same. But there's a reason for higher level languages.
IDK how man, but this video suddenly popped on my face after may 2 years when I know a bit more about computers and programming and I am able to comprehend more of what is going in this video.... And I just realiesed, This man is creating some real value dude....🔥
I was kind of lucky with my instructor. He's an old veteran who goes on rants of his experiences with writing in c and dealing with UNIX mainframes and talks a lot about all this underlying stuff which makes programs work.
This is an amazing video, you really have a gift for explaining complex matters in a clear way, shame this channel stopped uploading. Hope you are well!
I know you probably won't read this but still, I want to say this is my favourite computer science video on youtube. You explained things in such a clear manner and also not boring one bit. What's really special about your video is how you explain some of the concepts lecturers and others never teach. for eg the part where you talked about how compilers themselves are created. Thank You for the video
It's probably going to be exciting seeing the next generation jumping directly into Quantum Computing... I see a lot of confusion, flat lies and etc... but they will figure it out. what is possible, what is not and what is Politically Correct.
you didn't need semicolons back then semicolons are just to allow the programmer to set the end of an instruction in a high level language rather than having the compiler rely on line breaks so you can break it up into multiple lines for binaries, semicolons leave basically nothing behind unless it's a lone semicolon, which compiles into a nop, which is the only exception
Yeah.. I was expecting him to talk about transistors and what actually makes up a cpu. That's what reads it. I had to design one from scratch in one of my electrical eng classes
@Chris Russell They aren't building simple circuits using Ohm's Law (not electricians), electrical engineers learn the why and how of circuits using fourier, vector, and complex analysis. They don't just learn circuitry either, the 'weed out' classes constitute three semesters of physics, and four of calculus (if you count differential equations), next comes electrodynamics, thermodynamics, quantum mechanics, classical electromagnetics, the whole nine yards and more. It is extremely over the top conceptual and recognized as one of the harder engineering courses. So ya it's not just some piece of paper that the "HR people" give credence to. Electrical engineer is a set of tools used in almost any industry that uses electricity.
@Chris Russell I like how you so pompously tout your knowledge of elastance but brush off thermo. This comment is absolutely sceaming at me that you fancy yourself some tragic savant, doomed to mediocrity by the system that lets youngsters with a an embossed plaque to go on to bigger and better things. Save your schtick buddy, you just sound haughty and maybe a little jealous, else why are you even giving this spiel in the first place but to call yourself a gifted little star.
Instead of IDEs saying "EOS : End of expression expected at line : 40" They should just say "Add a semicolon at the end of line 40 ya dummy" Life would be easier this way.
Nor saying: "Semicolon Warning: Please put semicolon at the end of the line 40", or just adding a semicolon when running or the IDE finds the error. Dumb IDE Developers... Oh wait, I'm a IDE Developer.
I have been wondering about this for so long, not knowing was always a stone in my shoe, a disturbance in the force, it was. I knew the code had to be transferred into binary, but how? And, "Compiling the compiler with a previous version of itself", the sweetest poem I've heard in a long time. Thank you so much for this.
Thank you for putting EVERY tool and programming language you used in the Description!!! Sometimes I'm so confused on which programms were used in a video!
I have always been fascinated with compilers and how they work ever since I started to teach myself to write code. I teach myself out of hobby and to use my brain since I'm a bit older. Awesome video.
I think my university did it pretty well, first semester you take a class called "Computer Systems, Architecture, Networking and Security", and in that class you work with manually compiling written code to objects and then linking them in assembly then you also covert them to binary aswell, you also cover logic gates and in it some optimization compilers do to your code. It cover os architecture and network protocols and cryptography but I think it's important to understand object linking and compiling otherwise you'll get very confused when you start trying to use cmake and get 20 linking errora haha.
Jesus you must have gotten extremely lucky to have a CS track that was that exhaustive and explanatory, even sounds like it was using linux from the start too. I've been to a few different university CS courses and they've all been nothing like that. Maybe it's a culture thing but I WISH I got that sort of introduction to programming.
@@essayedgar Monash University in Melbourne, AUS. The unit itself isn't exhaustive in any of these topics by any means, however most of these topics are often fundamental to many career paths despite being overlooked in favour of more specialized practical work. But the relative broad coverage of many of these topics helps give a lot of context and elevates students' understanding of other units substantially. Often a lack of these fundamentals leads to elusive higher level problems the person is likely to struggle to identify and often results in trial and error learning of these concepts, or even worse where the student fails to learn these concepts completely which I see all too often result in zero-day security flaws in software they later release in their career.
damn lucky you..I'm doing btech CSE and all I got in first year was a lot of chemistry, physics, civil engineering and whatnot..literally wasted a year imo
10:40 I was so excited when I heard this. That's the exact question I've been wondering ever since I learned about compilers! Thanks for clearing it up, keep up the great work!
i found this video, and than i went to check out the cccs. a week later, i am here now again to say thank u - this video is a really good complementation to the cc. this is insane and mind blowing.
For someone who has zero experience in programming and interested in the field. This video was incredible helpful in understanding the origins of code and made a lot of sense. I can see why there are only linux and it's many distributions as the only real alternative in operating systems. It would take a lot of work and know how to reinvent the wheel. Great video.
@@half-qilin Python is very inefficient too, and is only a scripting language, plus it also requires the user to have all of the required libraries and the same major Python release installed, while a binary only requires the user to have the same OS, and potentially a few dynamic libraries, which in the case of Windows and Visual C++ (which also tends to apply to C if you use functions included in VCPP DLLs), the user very likely has them anyways, and with Linux and macOS it tends to be a little more complicated at times, but things generally are more backwards compatible than Python
@@TorutheRedFox I develop for MacOS or game consoles like the 3DS (when I’m not using Unity). I might consider using Java at some point, but IDK on that one.
@@half-qilin good job comparing a complied language to an interpreted language guys. it's not the case of different languages for different uses, it's definitely the case of one being better than the other. jeez better call all these research facilities and let them know they are using the wrong language.
I wish you will come back any time.. this videos are filled with lots of information and are quite funny so I wanted to watch the entire channel on one evening .. well.. it’s 12:30AM and I’m still watching 😅 Nice job!
This video perfectly answers all of the questions I had as a teenager twenty years ago. All the way up to "but how would the first compiler be written?" Thank you for introducing others to these questions. 😄
Man please keep making videos. You are the only chanel that answered all my questions in such a clear way without being afraid to go into a bit of math. And your humor is awesome as well. You are literally the best computer science chanel I found, it would be a shame to stop making such awesome videos. Hope we hear from you soon.
Compilers aren't actually as complicated as people tend to think. They can be, and the industry grade ones like gcc really are, but the core idea is really simple. Most people who know programming can write one (not without extensive googling of course), no cs/math degree is required for that. I'm speaking from experience as I've written a few of these things myself back in high school. In fact, I believe that everyone who considers themself a programmer should write a compiler to properly understand how it actually works, as in, "I don't understand it if I can't do it myself".
Yeah, like from what I heard almost half of gcc is just the optimization passes where they pull off some freaky shit. The actual translation and ast isn't that complicated.
@ex-xg5hh hope you're still acrive... may i ask what did you write in assembly? what was the purpose of the code? was it like some simple thing or a complex code like rollercoaster tycoon type of stuff
I remember writing a brainfuck compiler back when I was beginning C programming. It was fairly simple (brainfuck is literally designed to have a small compiler) but it helped me understand a bit about how compilers work.
When I read about compilers, it all start with lexical analysis, parsing, tokens, etc. But, you just built up an intuition. I got what you gave. Thanks!
Psychologically, if students start learning assembly language first, then they're exposed to high level language, they would grasp the concepts like super quick.
The thing about learning high level programming languages before lear ning things under the hood is that you dont understand why certain things dont make logical sense. For example why .1 +.2 is not equal to 3. This has nothing to do with the high level language itself but rather how math works with binary language.
Attrition would be way to high. There’s simply too many hurdles to learn low level and less intuitive languages for a beginner. Psychologically, it’s better to be able to start practicing very soon, like with python, rather than have to learn a ton before starting. I agree that starting from the bottom gives a better understanding, but I think beginners need to be able to have an easy way in. If you learn assembly or whatever first that’s good, but I don’t think it should be universal.
Well I did try when I was 12 and I was able to write HTML and CSS with ease but VB and C I just could not grasp. I stopped trying to program and stuck with the hardware side as a net admin and then later tried to pick up programming again. It does seam WAYYYYY easier than it was 18 years ago.
I had a similar experience at 12, with html and css, mainly for building out my old myspace page. Regretfully I didn’t revisit the subject for years to come.
Where are you? And why are you not making more videos like this. This is by far the best video i have ever seen. I have problem visualising stuff and because of that its harder to learn stuff. Your video actiually gave me good understanding of how programming actually works. Thanks for this.❤
"All you did was Python scripting?!" This line hit way too hard for me. I started in C++, like most kids in HS, forgot it, then went to Python. Now, I code in Rust more than anything else, but I remember that learning curve and feeling like I had no idea what was happening.
thanks for this video! I really like this for the reasons that: 1. You've shown concrete instructions, the assembly code with stack pointer not just some abstract idea. 2. The phases in compilation (analyses). 3. The part where you glossed over Java compiler and assembly topics, that Java compiler is a compromise for different CPU architecture and that assembly code is an intermediate step before the machine code now it made more sense to me, again thank you, please keep it up. I'm saving this vid.
Faster info: Compiler takes what you write and turns it into optimised assembly code -> object code -> links the objects etc etc and spits out a machine code executable. Also, some languages like Python, Java are interpreted at execution time thus making them slower.
Java source code is compiled to platform-agnostic bytecode, and then run in a virtual machine that will usually compile it to actual machine code on the fly nowadays, so dumping it alongside Python is just wrong. Python is a scripting language, while Java is not. It would be easier to compare Python to the likes of JavaScript and PHP since those are interpreted scripting languages too, although even those two languages have started to be used in tandem with Just-In-Time compilation in order to speed them up when needed.
I've always wondered about how the first program was developed. I guess programming is based on electronics in a very naturalistic and physical/chemical way with transistors etc. Amazing
the fact you explained it to us in such a detail just tells that you either had a very good experiecne with writing a compiler, or you had an experienced person check/write your text, or
I think it is cool to add that high-level or low-level are both relative to a specific machine, so Python is high-level to an Intel processor, but somewhat lower-level to the Python VM. Also note that there exists compilers that translate a high-level language to a language that would look like it is high-level comparing to an Intel processor. Also, JVM execution is more the complex then a "interpreter". Code is initially interpreted, but most used functions are compiled to native code on-the-fly and executed natively.
@Sam Erens The difference is basically that in mathematics every statement has to apply at the same time (unless specified otherwise) while in programming every statement only applies *once* (unless used multiple times [e.g. loops]).
9:58 "...when the program is run via an interpreter." An interpreter is a program that executes your source code as it reads it. For example, Python uses an interpreter.
Man! I have to thank you - I watched this video three months after it has been uploaded, and was a beginner in python. I thought "python is great and i will stick to that", but when you said "python scripting" I was absolutely amazed with this compiler magic and started learning C#, then Java, C++ and even x86 asm! Now, I came back to this video and realized, that without you, I would never learn these languages! Now I'm a junior Java Developer. Again, thank you so much.
Good luck to you. I looked at the 8086's assembly in DosBox for about 5 minutes and noped right out of there. Funny how the most popular CPUs have my least favorite assembly languages.
gcc compiled without the -O optimization flag won't perform anything other than minor optimizations that don't cause side-effects, like a variable being optimized away. Compiled with the -O0 flag, no optimizations will be made at all
Of course there are some exceptions, but most channels (especially the science-related ones) that are currently popular have been around for years, many have started all the way back in 2007 or so. Those exceptional channels grow so fast largely because they are being shared on other social media services, while most channels grow primarily through TH-cam recommendations and the occasional reference in other channels' comment sections.
Because the frequency with which he puts out videos is very low, almost once a year. I would recommend watching other videos. The Quantum computing ones are just too good.
@@tunis4 He's talking about python versions. The code `print "hello"` used to be correct in python version 2.7 but when python updated to version 3, they removed the feature. Although it's not as pretty, I agree with Python's decision to be more consistent with syntax. Another thing that changed was `/` being sometimes an integer devision and sometimes a float division (classic division like java), to `/` being only floating point division (true division). Now only `//` is used for integer division. (floor division)
I mean ... I lived through this many times. The amazement at how simple Python is, just print "This" and it works! No wait, that's the old python, the new one needs brackets.
i was learning how to code in python, then the guy on the video said "compilers and intrepreters are different, but do the same work basically", and now even if this haven't respond my question im glad to understand a little bit more about computers, this video is really cool and well explained!!
When you accidentally mix up the programming languages (or versions in this case) (I once tried to print to Serial Out in Java. Didn't work for some reason)
Whoever writes the compilers are absolute beasts
nah compilers are simple
@@hausemester7386 Writing GCC, LLVM is indeed "rocket-science".
simple? where is your complier?@@hausemester7386
@ well if you really did that then you are a genius
@@MygenteTV Nice logical fallacy.
my man just quit after making the best video about compilers, what a legend
I miss him.
What happened to him?
Giga chad move if he is alive. He prolly making agi. He so smart
When I started to learn how to write code years ago I was told "the computer is one of the dumbest machines, it only follows orders even if they are wrong", it really helped me shape my mind to understand the logic of many programs
Agreed
Self aware AI will remember this
"it only follows orders even if they are wrong"
humans don't?
M.L. and A.I. - Am I a joke to you 😂😂
@Nebula no, Human only use them for tedious tasks lmao
Mad respect to all the engineers behind compilers.
IT feels almost like something they would find inside of a crashed alien ship! xD
its not that difficult really. once you build one, its really consistent.
its a really fun project tbh.
i built an interpter so.
which is like a compiler with out the code gen.
shout out to my boy terry, the mad fella actually made an entire os (temple OS) from scratch, running on its own language (Holy C)
@@stinkyyy2k yea terry was amazing RIP
@@theowillis6870 that's not really the same as compiling.
Also, while it's true that the basics of compiling is easy.....
The sheer amount of optimising you have to do to make the compiler even remotely give a decently sized executable file is unreal
That's why most people have their language compile into something like LLVM, for example
"So our program is pretty boring right now, let's add a line to increment x by 1"
Hold up dude, you can't go that fast to such levels of complexity
hahaha holy shit im dyying
not even X++;
It was boring but now it is starting to get interesting baby.
@@yakinthebox not even x = 4;
@tutacat No
I remember this quote from the programming classes I took while getting my EE degree. I don't remember who it was attributed to, but...
"Computers always do what you tell them to do, and rarely what you want them to do."
Thanks for that amazing quote!
Ill share the one I liked:
There are 10 types of people in the world,
The ones that understand binary and those who don't
@@MauritsWilke you bitch
@@theguywhodoes6790?
@@pootzeketzi1233 he made a pun with binary
so true
When you know how computers work exactly, how the internet works and all that stuff, you get fascinated a lot.
Opposite.
Once you understand how it all works, it stops being "some magic".
Nikki yes, I mean you get fascinated about how humans made this and you start appreciating technology
@@Cyber_One Which is why i hate the technology these days, we went from changing humanity to wifi salt shakers.
@Vseslav Levchenko prove me wrong
@Yann cedric Totsingan im 22yo and studying CS lol your guess was off by a lot
Bro just casually dropped a banger and randomly vanished from TH-cam 😢
he literally mean it when he typed quit
In a push of a button...
no.. nope.. wait.....
-Programmer life story
A push of a button.
*Realizes he actually runs Python 3 instead of Python 2*
There we go. A push of a button.
50 errors laters, there are now 60 errors...
@@sublime_tv SO TRUE
I genuinely laughed out loud at that part, and I'm dead inside.
unexpected indent, syntax error, index out of range 😂
When I was teen (15 years ago), I was fascinated in programming. I remember spend a lot of hours on the computer trying to figure out how it works and why a code like "print("Hello world")" works in a machine level, but in that time internet didn't have this kind of videos (in fact, youtube was just beginning).
Nowadays with this kind of videos it's really easy learning about everything and I am still fascinated with computer (but now approaching it from neuroscience) and your skills to transmit this information, however are awesome.
Thanks a lot !
@killmoo almost, I'm 29 😅
ouuch that was hard understanding things like puts() in c because it use the system c lib (libc/glibc/musl on linux and msvcrt on windows
it just show picture not found thingy
@@Neurofilia right now I am 15 and learning this programming stuff
Even with rhe Internet it's still extrenely difficult to understand, if at all.
Processors are insanely complicated nowadays including how they execute instructions
"Source code is made only to be understandable to humans"
My brain cells: Ight imma head out
lol
Source code is sometimes only readable by its creator. I know my code falls victim to this
@@half-qilin exactly, reading people's code is a pain in a$$.
@@half-qilin well, on the bright side it could be more difficult for hackers.
Fortran: Hold my code
Honestly, the most interesting part was your description of how machine codd works. From the machine code to the output felt always like magic to me, and this starts to give meaning to what is really happening
This video managed to take a complex idea and compile it down in a form understandable to our human brains. Funny that :)
@Niepowtarzalny Użytkownik "decompilation" of how compilers work
Maybe .. but it also presented more unanswered questions :(
Me: "Computers work by doing magic."
Frame of Essence: "Here's how they actually work."
Me: "Computers work by doing 50x more magic than I thought they did."
Four years later this comment still deserves a like.
This is so mindblowing how this swaps the values, I have never seen this before:
x = x + y;
y = x - y;
x = x - y;
So x and y are 0...?
The Great Zoom no = in programming means "assignment". You assign the value on the right to the variable on the left. Even equations like x = x + 1 are possible. This would not work in mathematics for example, there = is a "comparison". In most programming languages comparison is defined as "==" which is not the same as "="
this would immediately cause a compile error because Y is undefined when you're initially assigning X using Y
@@TorutheRedFox yeah you have to define them otherwise the swapping would not even make sense
In Python, you could actually write it in one line as
x, y = y, x
which is a direct consequence of Python's unpacking. It is fundamentally different from the C-style approach though (as I understand it) because firstly, names in Python don't correspond directly to a location in memory and the y, x on the right is actually a tuple, more explicitly written as (y, x).
Bootstrapping (pull yourself up by your bootstraps / an impossible action) is to compile a compiler from its own source.
It's a chicken and egg situation. Which came first? The compiler? Or its self source? The compiler, born from another language.
The first C++ compiler originated from C. (Bjarne used C to create a C with Classes preprocessor. He used his C with classes language extension to create Cfront. Cfront compiled his C++ language into C. And that's why C and C++ mix together.)
The first C compiler originated from B. (B was first written for the PDP-7 minicomputer. (Programmed Data Processor) It evolved into NB (New B) to support the PDP-11. C was written in NB.)
The first B compiler was written in TMG. (TransMoGrifier)
The first TMG compiler was written in PDP-7 assembly language.
Assembly is machine code made readable. (directly from the opcodes. (operation codes))
Before Assembly, people would've likely used some form of custom assembly code on paper to translate into machine code.
Whoah, untold history, thanks now i can sleep in peace
It's not impossible though to write a compiler without using another high level language. Most early compilers and interpreters were written in assembly (for Fortran, Algol, Simula, Lisp, Basic, and so on). Some of them first wrote a simple compiler for a subset of the language in assembly and used it to compile a more advanced compiler (written in that subset, but implementing more of the language).
@@herrbonk3635 of course, but it wouldn't be worth it. the compiler will do the same exact translation you program it to do. the only difference would be how fast those compilers are at doing that. i think we'd take slightly slower compilations, for more well managed and developed compilers. that's the whole reason for higher level languages to begin with. to make development easier and more time efficient. hence why AAA games are written in C/C++, not assembly. we don't need the utmost potential possible out of most stuff. we'd rather have the darn thing finished already. and better compilers means better compiled code.
@@DlcEnergy Hmm, I wasn't discussing efficiency here, but rather principles from an historical perspective. I was under the impression that you did too. However, you somehow seem to miss my point about that interesting middle way between assembly coded and self hosting compilers, using a subset of the HLL implemented. It has been used also for relatively "modern" (at least when you are 50+) languages like Pascal and Modula.
I sure agree that compilation speed is much less important today, when everybody has "super computers" (in a very real mening, compared to the situation in the 1960s, or even the early 1990s). I personally love interpreted languages for their great flexiblity and security (checking array accesses, stack overflow, and so on).
And my own design of a HLL language happens to be a pretty slow(!) compiler with some aspects of typical interpreters that I find useful. It produces quick and efficient code though. (All statements and their syntax are implemented as fully redefinable operator functions in this language, with pre-, post- or infix syntax, hence its relatively slow parsing speed.)
@@herrbonk3635 That's why i'm bringing efficiency up. Obviously a lower level language can achieve the same. But there's a reason for higher level languages.
IDK how man, but this video suddenly popped on my face after may 2 years when I know a bit more about computers and programming and I am able to comprehend more of what is going in this video....
And I just realiesed,
This man is creating some real value dude....🔥
lol that python 2/3 joke at the end
edit: didnt realize this is just released 18 minutes ago, nice
Likewise the one at 1:08.
Nice easter-egg
Yatta Sovr That really doesnt have anything to do with the joke though.
HAHA! I was just going to comment the same thing!
That is why I still program in python 2
@@KingJellyfishII well you can convert python 3 to 2
and 2 to 3
I was kind of lucky with my instructor. He's an old veteran who goes on rants of his experiences with writing in c and dealing with UNIX mainframes and talks a lot about all this underlying stuff which makes programs work.
This is a damn near perfect video
This is an amazing video, you really have a gift for explaining complex matters in a clear way, shame this channel stopped uploading. Hope you are well!
>Programming isn't so hard...
*calls quit()*
Python's is exit()... lol
@@maybelbdidit In python you could use:
exit()
quit()
or if you import sys
sys.exit()
All these work.
Lolz
@@maybelbdidit Just try plugging out the power source. Works with every language.
@Irritating Would have been funnier if there was a single frame with an error.
"What you've only done python scripting!?"
*started on C++ and moved to java*
*sweating bullets from dodging a bullet*
you just dodged a bullet by jumping into a bigger and worse bullet
i started on Java and am now learning C++ :D
@@glzr_io python's syntax sucks and is slow
@@andrewdaniels5043 no
@@pepperoniboy57 yeah lol Java is better
I know you probably won't read this but still, I want to say this is my favourite computer science video on youtube. You explained things in such a clear manner and also not boring one bit. What's really special about your video is how you explain some of the concepts lecturers and others never teach. for eg the part where you talked about how compilers themselves are created.
Thank You for the video
he hasn't posted anything for 4 fucking years, and your comment was like 1 year ago
@@kakyoindonut3213 yeah. these videos are amazing but the channel is dead innit?
@@imibuks-replit maybe, 4 years is a really long time
@@kakyoindonut3213 yeah... for a few months yeah but almost half a decade....
I feel the same and I hope he gets back to TH-cam again!!
I remember watching this video a few years back and fascinated. Now I'm more than capable of creating my own programming language.
It's probably going to be exciting seeing the next generation jumping directly into Quantum Computing... I see a lot of confusion, flat lies and etc... but they will figure it out. what is possible, what is not and what is Politically Correct.
Imagine doing all the holes for old computer programs and then you realize you forgot a semicolon....
you didn't need semicolons back then
semicolons are just to allow the programmer to set the end of an instruction in a high level language rather than having the compiler rely on line breaks so you can break it up into multiple lines
for binaries, semicolons leave basically nothing behind unless it's a lone semicolon, which compiles into a nop, which is the only exception
@@TorutheRedFox it's a joke duh
@@gianmarcoproia5855 I know
Everybody: wow you write code that’s really hard
Me: you should see the people who write compilers
Everybody: What’s a compiler?
Me: its a program that turns source code into machine code
Everybody: whats source code and machine code?
As a language geek and conlanger, I'm so glad that I now know how compilers work. It inspires me.
As an AI Language Model.....
"How do computers read code?"
_by running code_
Yeah.. I was expecting him to talk about transistors and what actually makes up a cpu. That's what reads it. I had to design one from scratch in one of my electrical eng classes
Ever wondered how a computer compares to a human brain?
@Chris Russell They aren't building simple circuits using Ohm's Law (not electricians), electrical engineers learn the why and how of circuits using fourier, vector, and complex analysis. They don't just learn circuitry either, the 'weed out' classes constitute three semesters of physics, and four of calculus (if you count differential equations), next comes electrodynamics, thermodynamics, quantum mechanics, classical electromagnetics, the whole nine yards and more. It is extremely over the top conceptual and recognized as one of the harder engineering courses. So ya it's not just some piece of paper that the "HR people" give credence to. Electrical engineer is a set of tools used in almost any industry that uses electricity.
@Chris Russell I like how you so pompously tout your knowledge of elastance but brush off thermo. This comment is absolutely sceaming at me that you fancy yourself some tragic savant, doomed to mediocrity by the system that lets youngsters with a an embossed plaque to go on to bigger and better things. Save your schtick buddy, you just sound haughty and maybe a little jealous, else why are you even giving this spiel in the first place but to call yourself a gifted little star.
Can I throw some Lua in here?
This cleared so many of my doubts and made me take up computer engineering more passionately , thanks for changing my life
This video should be the mandatory pre-requisite for any and every concept of computer Science henceforth :) Amazing , So Thankful for you
@@ithaca2076 means worship on Hindi.
I absolutely agree! And to think it's only 12 minutes long!!! Why is this not shown to everyone who is learning to code?!
@@abcd123906 This is on YT. So, they will co e to know that they can basically learn all sorts of things on internet. And? college gone broke.
Instead of IDEs saying "EOS : End of expression expected at line : 40"
They should just say "Add a semicolon at the end of line 40 ya dummy"
Life would be easier this way.
Well, eventually your human brain will learn to compile that error message into an instruction to add a semicolon somewhere xD
or just use a a decent modern IDE that will underscore that missing semi-colon. less wasted energy and time.
Nor saying: "Semicolon Warning: Please put semicolon at the end of the line 40", or just adding a semicolon when running or the IDE finds the error. Dumb IDE Developers... Oh wait, I'm a IDE Developer.
And then python coders will be like, "what the f is the semicolon?"
@@spidercubed9718 notepad?! Pfft amateur. Real pros use punch cards
I first learned about all this 54 years ago. The knowledge served me well over the years.
tf?
I have been wondering about this for so long, not knowing was always a stone in my shoe, a disturbance in the force, it was. I knew the code had to be transferred into binary, but how?
And, "Compiling the compiler with a previous version of itself", the sweetest poem I've heard in a long time.
Thank you so much for this.
Just got past the intro and somehow I'm subscribed. Presentation so good it's an automatic yes
Thank you for putting EVERY tool and programming language you used in the Description!!! Sometimes I'm so confused on which programms were used in a video!
I have always been fascinated with compilers and how they work ever since I started to teach myself to write code. I teach myself out of hobby and to use my brain since I'm a bit older. Awesome video.
The best CS video I have ever watched
high quality content thats taken for granted
I think my university did it pretty well, first semester you take a class called "Computer Systems, Architecture, Networking and Security", and in that class you work with manually compiling written code to objects and then linking them in assembly then you also covert them to binary aswell, you also cover logic gates and in it some optimization compilers do to your code. It cover os architecture and network protocols and cryptography but I think it's important to understand object linking and compiling otherwise you'll get very confused when you start trying to use cmake and get 20 linking errora haha.
Jesus you must have gotten extremely lucky to have a CS track that was that exhaustive and explanatory, even sounds like it was using linux from the start too. I've been to a few different university CS courses and they've all been nothing like that. Maybe it's a culture thing but I WISH I got that sort of introduction to programming.
Where did you study?
I’m also curious what uni you’re talking about as this sounds lovely for a 1st semester class
@@essayedgar Monash University in Melbourne, AUS. The unit itself isn't exhaustive in any of these topics by any means, however most of these topics are often fundamental to many career paths despite being overlooked in favour of more specialized practical work. But the relative broad coverage of many of these topics helps give a lot of context and elevates students' understanding of other units substantially. Often a lack of these fundamentals leads to elusive higher level problems the person is likely to struggle to identify and often results in trial and error learning of these concepts, or even worse where the student fails to learn these concepts completely which I see all too often result in zero-day security flaws in software they later release in their career.
damn lucky you..I'm doing btech CSE and all I got in first year was a lot of chemistry, physics, civil engineering and whatnot..literally wasted a year imo
10:40 I was so excited when I heard this. That's the exact question I've been wondering ever since I learned about compilers! Thanks for clearing it up, keep up the great work!
i found this video, and than i went to check out the cccs. a week later, i am here now again to say thank u - this video is a really good complementation to the cc. this is insane and mind blowing.
How tf did humans figure out how to do this lmao
100 billion people * 40 years of thinking = quite a bit of progress 😅
My brain is getting roasted in a corner thinking the same....While I just completed watching this video.
@@TheInterestingInformerThat's not really just, quite a bit of progress TBH...💀
It took us approximately 300K years to figure this out(since homo sapiens spawned 😂)
Aliens 👽
For someone who has zero experience in programming and interested in the field. This video was incredible helpful in understanding the origins of code and made a lot of sense. I can see why there are only linux and it's many distributions as the only real alternative in operating systems. It would take a lot of work and know how to reinvent the wheel. Great video.
If you got zero experience about programming you wont understand what is being talked about in this video specially in the comments section!!!
TH-camr: "you've only been using python!?"
Me, who uses scratch: "uh, sure"
Rabot Carol
Web languages gang here
People less than 13 year old aren't allowed on TH-cam
@@gamermapper what
JS gang rise up
Where did he go I need him he explains stuff in a way I understand
Please give him back
That ending 😂
Pain of people who change from Py2 to py3
I try to avoid Python, it’s complicated to figure out after learning other languages. I prefer C over Python.
@@half-qilin Python is very inefficient too, and is only a scripting language, plus it also requires the user to have all of the required libraries and the same major Python release installed, while a binary only requires the user to have the same OS, and potentially a few dynamic libraries, which in the case of Windows and Visual C++ (which also tends to apply to C if you use functions included in VCPP DLLs), the user very likely has them anyways, and with Linux and macOS it tends to be a little more complicated at times, but things generally are more backwards compatible than Python
@@TorutheRedFox I develop for MacOS or game consoles like the 3DS (when I’m not using Unity).
I might consider using Java at some point, but IDK on that one.
@@half-qilin good job comparing a complied language to an interpreted language guys. it's not the case of different languages for different uses, it's definitely the case of one being better than the other. jeez better call all these research facilities and let them know they are using the wrong language.
I wish you will come back any time.. this videos are filled with lots of information and are quite funny so I wanted to watch the entire channel on one evening .. well.. it’s 12:30AM and I’m still watching 😅
Nice job!
This video perfectly answers all of the questions I had as a teenager twenty years ago. All the way up to "but how would the first compiler be written?" Thank you for introducing others to these questions. 😄
My man made the best CS video about compilers I've ever watched and the disappeared like the Avatar
Man please keep making videos. You are the only chanel that answered all my questions in such a clear way without being afraid to go into a bit of math. And your humor is awesome as well. You are literally the best computer science chanel I found, it would be a shame to stop making such awesome videos. Hope we hear from you soon.
the best video ever seen in my life about programming. you've done a wonderful job.
Compilers aren't actually as complicated as people tend to think. They can be, and the industry grade ones like gcc really are, but the core idea is really simple. Most people who know programming can write one (not without extensive googling of course), no cs/math degree is required for that. I'm speaking from experience as I've written a few of these things myself back in high school. In fact, I believe that everyone who considers themself a programmer should write a compiler to properly understand how it actually works, as in, "I don't understand it if I can't do it myself".
Yeah, like from what I heard almost half of gcc is just the optimization passes where they pull off some freaky shit. The actual translation and ast isn't that complicated.
@@usrnewxnew5227one quarter is parsing cause c++ is a very hard language to parse, the next is then optimization… witchcraft
@ex-xg5hh hope you're still acrive... may i ask what did you write in assembly? what was the purpose of the code? was it like some simple thing or a complex code like rollercoaster tycoon type of stuff
I remember writing a brainfuck compiler back when I was beginning C programming. It was fairly simple (brainfuck is literally designed to have a small compiler) but it helped me understand a bit about how compilers work.
Interpreters are probably easier to write tho since you can just run the code in the language of the interpreter instead of generating machine code
When I read about compilers, it all start with lexical analysis, parsing, tokens, etc. But, you just built up an intuition. I got what you gave. Thanks!
hats off to those who made compilers,struggeling behind the scene for making programming world so simple!
Damn, i thought this channel was over, I'm so happy he's back!!
aaaand he's dead
coming back soon!
@@frameofessence still waiting lol
@@frameofessence we miss u
@@frameofessence no pressure ofc, but I'm still waiting
Psychologically, if students start learning assembly language first, then they're exposed to high level language, they would grasp the concepts like super quick.
That’s not really true it’s easier to learn high level stuff first, and then to go under the hood
@@jaredvec5737 Yeah
@@jaredvec5737 I think the best way to learn is to start low, but high enough, but not so high. That's why college usually starts with c/c++
The thing about learning high level programming languages before lear ning things under the hood is that you dont understand why certain things dont make logical sense. For example why .1 +.2 is not equal to
3. This has nothing to do with the high level language itself but rather how math works with binary language.
Attrition would be way to high. There’s simply too many hurdles to learn low level and less intuitive languages for a beginner. Psychologically, it’s better to be able to start practicing very soon, like with python, rather than have to learn a ton before starting. I agree that starting from the bottom gives a better understanding, but I think beginners need to be able to have an easy way in. If you learn assembly or whatever first that’s good, but I don’t think it should be universal.
I like how Crash Course computer Science was mentioned, you are not mistaking dear sir, such as yourself they are very good at explaining.
10:30 caught me off guard but I LOVE IT!
I wish I didn’t wait until I was 18 to learn programming. I could’ve learned this shit easily at the age of 10. I think most people could.
AlphaOmega my thought exactly!
Well I did try when I was 12 and I was able to write HTML and CSS with ease but VB and C I just could not grasp. I stopped trying to program and stuck with the hardware side as a net admin and then later tried to pick up programming again. It does seam WAYYYYY easier than it was 18 years ago.
I had a similar experience at 12, with html and css, mainly for building out my old myspace page. Regretfully I didn’t revisit the subject for years to come.
Ya know, I am just a freshmen, and Java is quite nice to use. Not saying the same for JavaScript, but I am saying that about Java itself.
I used to teach a programming class to 7-12 year olds. It's definitely a thing.
This is just going through my ear and out the other. I’ll probably have to watch it at least 5 times until I understand. 💀
Where are you? And why are you not making more videos like this. This is by far the best video i have ever seen. I have problem visualising stuff and because of that its harder to learn stuff. Your video actiually gave me good understanding of how programming actually works. Thanks for this.❤
"All you did was Python scripting?!"
This line hit way too hard for me. I started in C++, like most kids in HS, forgot it, then went to Python. Now, I code in Rust more than anything else, but I remember that learning curve and feeling like I had no idea what was happening.
Just one word :
Amazing!!!
wow better than most classes I took in college hahaha
The dead inside laugh "hahaha"
this is key to creating safety measures once i understood what exactly programming language is.
thanks for this video! I really like this for the reasons that:
1. You've shown concrete instructions, the assembly code with stack pointer not just some abstract idea.
2. The phases in compilation (analyses).
3. The part where you glossed over Java compiler and assembly topics, that Java compiler is a compromise for different CPU architecture and that assembly code is an intermediate step before the machine code
now it made more sense to me, again thank you, please keep it up. I'm saving this vid.
Faster info: Compiler takes what you write and turns it into optimised assembly code -> object code -> links the objects etc etc and spits out a machine code executable.
Also, some languages like Python, Java are interpreted at execution time thus making them slower.
java is closer to being JITed than intepreted, same with C#
Java source code is compiled to platform-agnostic bytecode, and then run in a virtual machine that will usually compile it to actual machine code on the fly nowadays, so dumping it alongside Python is just wrong. Python is a scripting language, while Java is not.
It would be easier to compare Python to the likes of JavaScript and PHP since those are interpreted scripting languages too, although even those two languages have started to be used in tandem with Just-In-Time compilation in order to speed them up when needed.
I've always wondered about how the first program was developed. I guess programming is based on electronics in a very naturalistic and physical/chemical way with transistors etc. Amazing
This has to be the funniest and one of the most engaging explanations I have seen on TH-cam😂😂
the fact you explained it to us in such a detail just tells that you either had a very good experiecne with writing a compiler, or you had an experienced person check/write your text, or
Beautiful video content and editing. Thank you for your efforts. ♥
I think it is cool to add that high-level or low-level are both relative to a specific machine, so Python is high-level to an Intel processor, but somewhat lower-level to the Python VM. Also note that there exists compilers that translate a high-level language to a language that would look like it is high-level comparing to an Intel processor.
Also, JVM execution is more the complex then a "interpreter". Code is initially interpreted, but most used functions are compiled to native code on-the-fly and executed natively.
Whoever writes the compilers are absolute BEASTS
As a maths person and someone who's never done any coding, seeing "X = X + 1" pained me to read.
X-x = 1 0=1😂😂*just joking*
@Sam Erens The difference is basically that in mathematics every statement has to apply at the same time (unless specified otherwise) while in programming every statement only applies *once* (unless used multiple times [e.g. loops]).
Yeah, it's more like a X(n+1) = X(n) +1 situation.
9:58 "...when the program is run via an interpreter."
An interpreter is a program that executes your source code as it reads it. For example, Python uses an interpreter.
He is saying the bytecode gets interpreted
Man! I have to thank you - I watched this video three months after it has been uploaded, and was a beginner in python. I thought "python is great and i will stick to that", but when you said "python scripting" I was absolutely amazed with this compiler magic and started learning C#, then Java, C++ and even x86 asm! Now, I came back to this video and realized, that without you, I would never learn these languages! Now I'm a junior Java Developer. Again, thank you so much.
Good luck to you. I looked at the 8086's assembly in DosBox for about 5 minutes and noped right out of there. Funny how the most popular CPUs have my least favorite assembly languages.
Want to know all from the low level transistors to high level web sites and apps in detail, would love to see a series on that : D
Thank God You're back...now dont go on long vacations...
pretty sure the program at 3:58 would be optimized out by the compiler because x is never used...
I thought so too, but gcc didn't do that for some reason.
gcc compiled without the -O optimization flag won't perform anything other than minor optimizations that don't cause side-effects, like a variable being optimized away. Compiled with the -O0 flag, no optimizations will be made at all
+
NoHomeLike 192.168.8.1
Nice and clear. At my work place, I have a colleague whose compiler doesn't raise an issue when he leaves variables unused.
Wouldn't the compiler throw a syntax error because main is an integer method, but there is no value returned?
I enjoyed watching this. Good sense of humour
I also watched the entire computers science series a year ago, it was fantastic.
Where??
Part TedEd, part ViHart, part Exurb1a. Why so few subs?
The most likely explanation is that this is a fairly new channel.
More than 3 years fairly new? Look at Jake Paul......
Of course there are some exceptions, but most channels (especially the science-related ones) that are currently popular have been around for years, many have started all the way back in 2007 or so.
Those exceptional channels grow so fast largely because they are being shared on other social media services, while most channels grow primarily through TH-cam recommendations and the occasional reference in other channels' comment sections.
It's because he posts very rarely. If be goes to once a week, the channel will get big fast.
Because the frequency with which he puts out videos is very low, almost once a year. I would recommend watching other videos. The Quantum computing ones are just too good.
Damn that ending... 3 > 2.7 :D
I concur, Python is just the worst.
hahah same here.
@@renxula why
@@omertrnk5397 it makes no sense for me
@@tunis4 He's talking about python versions. The code `print "hello"` used to be correct in python version 2.7 but when python updated to version 3, they removed the feature.
Although it's not as pretty, I agree with Python's decision to be more consistent with syntax. Another thing that changed was `/` being sometimes an integer devision and sometimes a float division (classic division like java), to `/` being only floating point division (true division).
Now only `//` is used for integer division. (floor division)
10:37 "All thanks to the people who wrote the special program; THE COMPILER" *background music ends dramatically*
*The EN*- BUT.
Oh. Okay.
i love how he stopped in between and correctly telling my situation
Oh god! The ending!
I was eating goddammit!
I nearly spat potato chips all over my keyboard!
lololololol hope you learned your lesson! :)
I didnt get it please explain
I mean ... I lived through this many times.
The amazement at how simple Python is, just print "This" and it works!
No wait, that's the old python, the new one needs brackets.
You should eat more healthy
@@potato_x69 Let's call the whole thing off
I still remember what i was doing when this video was uploaded, more than 3 years ago. Boy does time fly by fast...
PS: Please come back, yes?
bruh, you went above and beyond the explanations that my professors could never get to. I take my Mr. Robot hat to you...
Enrique P I haven’t been able to watch season 3 of mr. Robot is it good?
Better of season 2.
i was learning how to code in python, then the guy on the video said "compilers and intrepreters are different, but do the same work basically", and now even if this haven't respond my question im glad to understand a little bit more about computers, this video is really cool and well explained!!
when he said "now heres the problem", im like ...dude everything in this video is a problem
11:33 programming in a nutshell
When you accidentally mix up the programming languages (or versions in this case)
(I once tried to print to Serial Out in Java. Didn't work for some reason)
I can't even imagine myself ever making a compiler for an programming language!
That's like an Avenger-level shit
am going to make one. still learning. its a huge task but its not very difficult
Imagine that Bill Gates did so: He wrote the BASIC compiler...
@@JoshuaKisb did any of you make one already ?
@@boulahchichenadir9075 yeah sort of
@@JoshuaKisb sort of is still an improvement i geusse
when 12 min video in youtube makes you understand more about a class you ve been having over and over again
Having been self taught and not knowing this lower level stuff, this was very helpful! :)
Bro...why did you stop bro 😭....please come back
Could I give you more thumbs up!?
Well done.
Turing dream machine frame works.
"You only did python scripting?!"
me, trying to teach myself python:
Ah the nostalgia of no intellisense , turbo cpp , the blue old coloured screen , but now it's all changed , for good ofcourse :D
Where did this amezing guy go?
I almost never comment on videos, but I'm here to say that this explanation was just amazing