FAWK: LLMs can write a language interpreter

> And it did it.

it would be nice when people do these things give us a transcript or recording of their dialog with the LLM so that more people can learn.

Yes! This. It'd take so little effort to share, thereby validating your credibility, providing value, teaching,... it's so full of win I can't understand why so few people do this.

In my case, I can't share them anymore because "the conversation expired". I am not completely sure what the Cursor Agent rules for conversations expiring are. The PR getting closed? Branch deleted?

In any case, the first prompt was something like (from memory):

> I am imagining a language FAWK - Functional AWK - which would stay as close to the AWK syntax and feel as possible, but add several new features to aid with functional programming. Backwards compatibility is a non-goal. > > The features: > * first-class array literals, being able to return arrays from functions > * first-class functions and lambdas, being able to pass them as arguments and return them from functions > * lexical scope instead of dynamic scope (no spooky action at a distance, call-by-value, mutations of an argument array aren't visible in the caller scope) > * explicit global keyword (only in BEGIN) that makes variables visible and mutable in any scope without having to pass them around > > Please start by succintly summarizing this in the README.md file, alongside code examples.

The second prompt (for the actual implementation) was something like this, I believe:

> Please implement an interpreter for the language described in the README.md file in Python, to the point that the code examples all work (make a test runner that tests them against expected output).

I then spent a few iterations asking it to split a single file containing all code to multiple files (one per stage, so eg. lexer, parser, ...) before merging the PR and then doing more stuff manually (moving tests to their own folder etc.)

EDIT: ah, HN screws up formatting. I don't know how to enforce newlines. You'll have to split things by `>` yourself, sorry.

It stands to reason that if it was fairly quick (from your telling) and you can vaguely remember, then you should be able to reproduce a transcript with a working interpreter a second time.

To be clear: I'm not challenging your story, I want to learn from it.

Thank you! Great reply, much appreciated.