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Vladimir Keleshev

@keleshev.com

806 followers 438 following 57 posts

OCaml programmer, author of Compiling to Assembly from Scratch: keleshev.com/cas Copenhagen

Posts Replies Media

Vladimir Keleshev @keleshev.com · 18/08/2025

He was no Rafael, but look at this piece, could have been a banger punk rock cover!

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Vladimir Keleshev @keleshev.com · 15/05/2025

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.

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Vladimir Keleshev @keleshev.com · 03/05/2025

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))

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Vladimir Keleshev @keleshev.com · 02/05/2025

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))

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Vladimir Keleshev @keleshev.com · 22/12/2024

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.

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Vladimir Keleshev @keleshev.com · 20/11/2024

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:(||)

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Vladimir Keleshev @keleshev.com · 01/11/2024

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

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