notes

Stack substrate IL ideas from Kitten

Syntax

Quotations: [...]
Definition: define word [...]

Whitespace control flow

call word: word
jmp word: [word] jmp (generates a label, if the quotation is not a single word)
jz word: [word] COND jz or [word] [] COND if
jz word: [word] COND jz or [word] [] COND 0= if
jn word: [word] COND jn or [word] [] COND neg? if

Or without using quotes, also have a label quote: %word

%word jmp
%word COND jz
%word COND jn

That removes the incongruence, where a quotation is local like a lambda, but a jmp is to a non-local label.

More idiomatically, jz and jn can be written as if, but I think I want to keep lower-level conditional branching (maybe find a name that unifies the two; br?).

%word COND 0 = br
%word COND 0 < br
[word] [] COND 0 = if

(How to do then-only ifs?)

I can build further abstractions using labels on top of that, such as switch. Then, I can desugar quotations to generated labels.

Kind of like Racket cond:

[then1] [1 =] cond
[then2] [2 =] cond
[then3] [3 =] cond
[else] else

To avoid successive conditions after the matching one from being evaluated, maybe the conditions need to be quoted?

This is ugly, but would do the trick:

[[[[then1] 1= cond]
   [then2] 2= cond]
   [then3] 3= cond]
   [else] else]

Hmm. If I’m understanding if with quotations correctly, it must be syntax sugar or something, in order for the quotation to be ignored for the condition, e.g., in [then] [else] dup = 0 if, the dup would refer to the element under the first quotation.

Types

Statically-typed.

Type specification:

Values need not be named, but can optionally be
Maybe like Haskell, Kitten, or strict Forth comments

Types as values:

Inferred types with Coq {T} syntax
Like Zig comptime types; no runtime representation

Strategies for code reuse:

Generics like Rust with traits that scope words to the types
Quotations (e.g., compare and swap for quicksort)

IRs

With quotations and labels
Quotations lowered to generated labels

This site is open source. Improve this page.