Vladimir Keleshev
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keleshev.com
Vladimir Keleshev
@keleshev.com
780 followers 440 following 55 posts
OCaml programmer, author of Compiling to Assembly from Scratch: https://keleshev.com/cas

Copenhagen
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keleshev.com
He was no Rafael, but look at this piece, could have been a banger punk rock cover!
Onfim’s drawing of two people
August 18, 2025 at 9:59 AM
keleshev.com
Onfim was not the greatest artist, but why do you have to rub it in like that?!
A probable self portrait by Rafael, drawn when he was around the same age (1499), Ashmolean Museum, Oxford, UK.
May 15, 2025 at 9:09 PM
keleshev.com
Like, what language is this?
@dataclass class Parser[T]: parse: Callable[[Source], ParseResult[T] | None] @staticmethod def regexp(regexp: Pattern) -> Parser[str]: return Parser(lambda source: source.match(regexp)) @staticmethod def constant[U](value: U) -> Parser[U]: return Parser(lambda source: ParseResult(value, source))
May 3, 2025 at 10:21 AM
keleshev.com
Glad to see that Python finally got more dedicated syntax for type annotations in 3.12. Now it looks quite decent. So I updated the Python version of the book's compiler to use the new syntax: github.com/keleshev/com...
@dataclass class Parser[T]: _parse: Callable[[Source], ParseResult[T] | None] def parse(self, s: Source) -> ParseResult[T] | None: return self.__dict__['_parse'](s) @staticmethod def regexp(regexp: Pattern) -> Parser[str]: return Parser(lambda source: source.match(regexp)) @staticmethod def constant[U](value: U) -> Parser[U]: return Parser(lambda source: ParseResult(value, source))
May 2, 2025 at 7:52 PM
keleshev.com
I got two Pi 400 originally as Minecraft devices for kids on Christmas, but since then they are not using it much for Minecraft, more for Math Academy and school stuff. We got Nintendo Switch since then, so most gaming moved there.
Two Raspberry Pi 400 wrapped in Minecraft gift paper.
December 22, 2024 at 4:10 PM
keleshev.com
Excellent! Now use fold.

gist.github.com/keleshev/36e...
let size = fold ~leaf:(const 1) ~node:(+) let height = fold ~leaf:(const 1) ~node:(fun l r -> 1 + max l r) let to_string leaf = fold ~leaf ~node:(sprintf "(%s %s)") let reverse = fold ~leaf ~node:(fun l r -> node r l) let map f = fold ~leaf:(f >> leaf) ~node let bind f = fold ~leaf:f ~node let iter f = fold ~leaf:f ~node:(fun _ _ -> ()) let for_all predicate = fold ~leaf:predicate ~node:(&&) let exists predicate = fold ~leaf:predicate ~node:(||)
November 20, 2024 at 9:56 AM
keleshev.com
The grammar. The parser. I love doing this.
# Recursive definition of pattern required <- "(" _ pattern ")" _ optional <- "[" _ pattern "]" _ confined <- required / optional / atom _ multiple <- confined ("..." _)? sequence <- multiple multiple* junction <- sequence ("|" _ sequence)* pattern <- junction let rec pattern x = let required = token "(" %> pattern <% token ")" in let optional = let+ pattern = token "[" %> pattern <% token "]" in Pattern.Optional pattern in let confined = required / optional / atom in let multiple = let+ pattern, ellipsis = confined <%> maybe (token "...") in if ellipsis = None then pattern else Pattern.Multiple pattern in let sequence = let+ first, rest = multiple <%> zero_or_more multiple in List.fold_left Pattern.sequence first rest in let junction = let+ first, rest = sequence <%> zero_or_more (token "|" %> sequence) in List.fold_left Pattern.junction first rest in junction x
November 1, 2024 at 9:20 PM