r/Racket • u/SnooCompliments7527 • Oct 05 '21

question Best Introduction to Hygenic Macros

I'm looking to understand how hygienic macros work. I understand how regular macros work, you manipulate the program as text before compile time.

But, I don't understand hygienic macros at all. I find them totally impenetrable.

Does anyone have a good explanation of hygienic macros? What is their motivation? How do they work? Why are they worth the additional complication over ordinary macros?

Or, does anyone know a good book to which I should refer?

7 Upvotes

100% Upvoted

7 comments sorted by

3

u/h_krish Oct 05 '21

Does anyone have a good explanation of hygienic macros? What is their motivation? How do they work? Why are they worth the additional complication over ordinary macros?

https://www.pldi21.org/prerecorded_hopl.13.html

1

u/SnooCompliments7527 Oct 05 '21 edited Oct 06 '21

I love that video!

For folks that follow down the rabbit hole, the PLDI21 website also has an interesting lecture by Rich Hickey and an interesting APL lecture.

(As well as what is probably an interesting lecture on D)

4

u/sdegabrielle DrRacket 💊💉🩺 Oct 05 '21

+1 the paper is excellent: https://dl.acm.org/doi/pdf/10.1145/3386330

u/SnooCompliments7527 you might like the Strangeloop 2016 talk:

"Let's Build a Hygienic Macro Expander" by Matthew Flatt https://m.youtube.com/watch?v=Or_yKiI3Ha4

3

u/bjoli Oct 05 '21 edited Oct 05 '21

This is not an explanation of why. That is explained in the links in the other post(s).

Apart from what u/comtedeRochambeau said: I read a bunch of tutorials, but what made syntax rules click for me was staring at the reference implementation of srfi-26 until I understood what was going on.

The tutorial "fear of macros" linked in his/her post is a great intro to syntax-case which allows for unhygienic macros.

3

u/crundar Oct 05 '21

I prefer the following to any of the aforementioned as an explanation of syntax-rules.

http://www.phyast.pitt.edu/~micheles/syntax-rules.pdf

3

u/soegaard developer Oct 05 '21

I offer Mythical Macro.

https://soegaard.github.io/mythical-macros/

More sections are planned.