A dynamic tutorial about a compiler in one JavaScript file (2016)

github.com

65 points·roramigator··7 comments

Past related threads:

An ultra-simplified example of a modern compiler written in JavaScript - https://news.ycombinator.com/item?id=22522208 - March 2020 (27 comments)

Super Tiny Compiler - https://news.ycombinator.com/item?id=11395656 - March 2016 (100 comments)

And it's super readable too. Very concise but descriptive. The author has a friendly tone and the code is easy to follow, even if you're not familiar with javascript syntax. Good fun!

It would be my instinct to hoist the walk() function out of the parse() function but that's because my compiler writing experience is limited to C and Pascal. What is the thinking behind this decision? Not criticism, just trying to learn Javascript better

Local functions like that make sense if you want to access the outer function’s state - which is what’s happening here with `current`. It also makes it so others can’t use that function without having to make a separate module. Almost like a scoped “global” state. See also: IIFEs: https://developer.mozilla.org/en-US/docs/Glossary/IIFE

Of course! Totally obvious… Now that you bring it up! That’s much nicer than my non-scoped instinct. Thank you.

You can just link the original file https://github.com/jamiebuilds/the-super-tiny-compiler/blob/...

Changed from https://gist.github.com/roramigator/3806a55947b11bf9e27c4233.... Thanks!

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