Let's Write an Interpreter (in 168 Lines of Python)

I explain the inner workings of a computer language interpreter that features code blocks, error messages, comments, integer and string variables, math expressions, if-else, while-break, print, input, and subroutine calls. I build on the fantastic work by Jack W. Crenshaw. The interpreter only uses low-level Python.

"Let's Build a Compiler" by Jack W. Crenshaw:

Minimal UART CPU System on GitHub:

Minimal User Manual and Reference:

[stupossibleify]

Always viewed interpreters as beig indistinguishable from magic, this video goes a long way to demystifying the methods. Thank you

[StasPakhomov-wjnn]

I went through this line by line and re-wrote it locally in my language of choice, and it worked! I have to say, I've followed quite a few tutorials but none have been as magic as this one.

I must warn people going through this in the future that he reminded us that he is building things in a simplified way, thus avoid OOP and other heavier utilizations. Thus, it is a little hard to follow as everything is one big jumbled implementation as opposed to it being broken up into SRP components.

Amazing though nonetheless, I had a great time re-writing it locally to be in OOP as well :)

[RelayComputer]

That's very neat indeed. I love the use of a /single/ dictionary for all kinds of identifiers. That's quite cool !

[eboatwright_]

This is a really good video! I'm currently making my own programming language called King in JavaScript, so this was very insightful :D

[BryanChance]

Wow.. brilliantly explained! Thank you sir!

[funwithalbi]

this complicated task was done so simply!

[jimbailey]

Thank you for this very informative walkthough

[hamzacasdasdasd]

heres the entire python interpreter rewritten in python in just 1 line
exec("code")

[fusn]

Bro has a degree on writing unreadable python code.

[alessiocaffi]

Yes this is very informative and awesome, Slu4 Thanks. Tiny C would be nice to see. Cheers.

[xyzzyx]

Lua could be a good candidate! Or maybe micro-Lua (whatever it is... hahaha!)

[Borszczuk]

Hm, you do not seem to be too good in following naming conventions :)

[hahayes]

you can just tell he intentionally formatted it terribly for the 168 lines title

[zlatkovidlanovic]

Ok ..where is code of this 168 lines of python code ..?

[halfsourlizard]

Fusing your lexer/parser/evaluator is a terrible/unscalable way to write an interpreter.