←back to thread

Everything Is Just Functions: 1 week with David Beazley and SICP

(ezzeriesa.notion.site)
389 points kurinikku | 5 comments | 17 Nov 24 15:07 UTC | HN request time: 1.081s | source
Show context
liontwist ◴[17 Nov 24 16:26 UTC] No.42165013[source]▶
The cons/car/cdr implementation as lambda was magical the first time I saw it. But it just shows that the language runtime must implement key/value dictionaries and you are able to borrow that implementation to make other data structures.
replies(3): >>42165632 #>>42166573 #>>42203090 #
1. hinkley ◴[17 Nov 24 19:50 UTC] No.42166573[source]▶
I find the destructuring logic in elixir much more interesting, and the watered down version in ES6 much more practical.

In elixir you can pop off as many as you like.

replies(1): >>42166784 #
2. liontwist ◴[17 Nov 24 20:14 UTC] No.42166784[source]▶
Can you share any resources about it?
replies(1): >>42167135 #
3. hinkley ◴[17 Nov 24 20:53 UTC] No.42167135[source]▶
I’m a bit of an elixir noob, but Enum functions like slice let you cut up lists in various ways, and you can pattern match values in maps in function definitions:

http://www.skuunk.com/2020/01/elixir-destructuring-function....

Which can let you unroll function preambles, or apply different rules if for instance an admin user runs a function versus a regular user.

replies(1): >>42168091 #
4. liontwist ◴[17 Nov 24 22:52 UTC] No.42168091{3}[source]▶
I think this is a little different. Pattern matching gives you car and cdr, but not cons.
replies(1): >>42168217 #
5. hinkley ◴[17 Nov 24 23:16 UTC] No.42168217{4}[source]▶
That exists for maps and lists.