Thread

1. dharmatech · 1790874505 · focus · HN ↗

   I've been messing around with a language that I summarize as:

   ALOE = Scheme + Smalltalk + Types

   <a href="https:&#x2F;&#x2F;github.com&#x2F;dharmatech&#x2F;2026-09-02-aloe-racket" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;dharmatech&#x2F;2026-09-02-aloe-racket

   Prototype is in Racket.

   1. attila-lendvai · 1790888416 · focus · HN ↗

      you lost me at the receiver selector order.

      1. Jtsummers · 1790890007 · focus · HN ↗

         It&#x27;s a common way to implement OO in Lisp-y languages, and it fits if you&#x27;re taking Smalltalk as an inspiration. SICP has an example in chapter 3 (IIRC) of doing the same, but the selector had to be quoted as in:

           (my-account 'balance)
           (my-account 'withdraw 10)

         1. so-cal-schemer · 1790893070 · focus · HN ↗

            Uses an internal lambda for dispatching on messages.

            We can also create objects that handle deposits as well as withdrawals, and thus we can represent simple bank accounts. Here is a procedure that returns a “bank-account object” with a specified initial balance:

              (define (make-account balance)
                (define (withdraw amount)
                  (if (>= balance amount)
                      (begin (set! balance 
                                   (- balance amount))
                             balance)
                      "Insufficient funds"))
                (define (deposit amount)
                  (set! balance (+ balance amount))
                  balance)
                (define (dispatch m)
                  (cond ((eq? m 'withdraw) withdraw)
                        ((eq? m 'deposit) deposit)
                        (else (error "Unknown request: 
                               MAKE-ACCOUNT" m))))
                dispatch)
            

            Each call to make-account sets up an environment with a local state variable balance. Within this environment, make-account defines procedures deposit and withdraw that access balance and an additional procedure dispatch that takes a “message” as input and returns one of the two local procedures. The dispatch procedure itself is returned as the value that represents the bank-account object. This is precisely the message-passing style of programming that we saw in 2.4.3, although here we are using it in conjunction with the ability to modify local variables.

            3.1.1 Local State Variables

            <a href="https:&#x2F;&#x2F;sarabander.github.io&#x2F;sicp&#x2F;html&#x2F;3_002e1.xhtml#g_t3_002e1_002e1" rel="nofollow">https:&#x2F;&#x2F;sarabander.github.io&#x2F;sicp&#x2F;html&#x2F;3_002e1.xhtml#g_t3_00...

            1. Jtsummers · 1790893674 · focus · HN ↗

               A closure, specifically, because closures are a poor man&#x27;s object.

               <a href="https:&#x2F;&#x2F;wiki.c2.com&#x2F;?ClosuresAndObjectsAreEquivalent" rel="nofollow">https:&#x2F;&#x2F;wiki.c2.com&#x2F;?ClosuresAndObjectsAreEquivalent

               1. apgwoz · 1790901540 · focus · HN ↗

                  You fool! Objects are a poor man’s closures!

                  1. [deleted] · 1790931450 · focus · HN ↗

                     [deleted]

         2. dharmatech · 1790901491 · focus · HN ↗

            Yup!

            Here&#x27;s a video demo of the code completion in vscode:

            <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=YuIjug7elPY" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=YuIjug7elPY

Unofficial Hacker News client; not affiliated with Y Combinator.