Traditional S-expressions, by their definition, ignore most of whitespace; additionally, reading sexprs is always a linear operation without the need to backtrack by more than one character.
The suggestion from this post violates both assumptions by introducing a 2D structure to code. To quote this post's examples, it requires the multiline string in
(fst-atom """ trd-atom)
00001
00002
00003
"""
to be fully read before TRD-ATOM. It also forces the reading function to jump up and down vertically in order to read the structure in
* ( )
* e ( ) ( )
* q m ( ) p ( ) *
u a a o a 2 *
l w *
It gets worse/better. Since Racket allows you to hook your own reader in front of (or in place of) the default reader, you can have things like 2D syntax:
Truth be told, you can intercept the reader in Common Lisp, too, and here it actually makes some sense since the 2D value is immediately visually grokkable as an ASCII-art table. The proposed 2D sexpr notation does not have this.
I’ve seen dozens of attempts to make S-Exp “better” even the original M-Exp. I also did some experiments myself. But at the end, I come back to goo’ol s-exp. Seems to be a maximum (or minimum) found just perchance.
Not sure if that example helps. You can make any programming language hard to read without some basic formatting. The way I would write the sexpr would be:
(impl
(impl
p
(impl q r))
(impl
(impl p q)
(impl p r)))
It's clear when each section begins and ends and doesn't require complex parsing rules.
Related but not the same at all, Racket has a 2D syntax (add on mode) that gives a different way to program tables where the output depends on two different inputs.
Feels like the complete opposite s-expressions which are the easiest possible thing to parse, this sounds like a complete nightmare to write a parser for.
It might even be easier to treat the input string as a 2D grid than as a sequence and have a parsing head that behaves like a 2x2 convolutional kernel...
This would make for either a great Advent of Code, or a nightmare interview question, I love it.
Actually it's quite simple. We parse from left to right. When we hit EOL, we return to the beginning of line and increase Y by one.
Blocks are parsed in the following way: when we get the beginning count of block opening characters, we move Y by one, loop right while whitespace, until we encounter ending count of block characters.
In transposed block, we just switch X and Y, it is easily done with pointers, and use the same code.
I'll piggyback with my gruesome JSONification of S-expressions. I kinda liked having two kinds of braces [straight] and {curly} to differentiate arrays and objects, and I did have a event-loop-based "parallel" scheduler working to process a tree as soon as prerequisites were fulfilled. I might pick up the old project again someday, I just got hung up on how I wanted to handle error bubbling.
With a vertical script like japanese you could easily rotate the whole program 90 degrees to the right (as shown at the bottom of the landing page)
{
"#!join": [
[
"A triangle with side of ",
"#& side",
" and base of ",
"#& base",
"has a hypotenuse of",
{
"#!sqrt": [
[
{
"#!sum": [
[
"#!multiply side side",
"#!multiply base base"
]
]
}
]
]
}
]
]
}
This is fine and interesting, but what I think is lacking in S-expression isn't funky vertical syntax, but a way to directly represent objects that are not lists. Otherwise one needs to invent some representation on top of S-expressions (and then a list isn't necessarily a list anymore; everything goes through an additional layer of encoding/decoding, losing the elegance of S-expressions), or use some extension syntax (usually involving '#'), which varies from language to language and might not even be interpreted by the reader (but logically expand to some list expression that needs to be interpreted again later, so you're not really any better off than with the first approach).
I kind of want something like, to borrow JSON-like syntax and gloss over namespacing issues:
(foo .
{type: listy-cons-cell
head: bar
tail: (baz quux)})
...which would be another way to say (foo bar baz quuz), but would make it possible to represent any data structure you like at the same level as atoms, strings, and lists.
I don't get why anyone even tries after Clojure. They got it 100% right. It's easier to read than anything else, and still super simple to parse. Commas are whitespace, use them or don't, where ever you want. Namespaced keywords are great. The data structures themselves act as functions. It's just... done.
Kernel has first-class environments which aren't just lists, but can be constructed from lists. Environments are encapsulated, so we can't simply peek into them with car and cdr - we can only obtain the value associated with a given symbol by evaluating the symbol in that environment.
We could perhaps make something a bit more friendly. Lets create an encapsulated `struct` type which could give us the contents as a plain list, or let us look up each field:
Readit News
Traditional S-expressions, by their definition, ignore most of whitespace; additionally, reading sexprs is always a linear operation without the need to backtrack by more than one character.
The suggestion from this post violates both assumptions by introducing a 2D structure to code. To quote this post's examples, it requires the multiline string in
to be fully read before TRD-ATOM. It also forces the reading function to jump up and down vertically in order to read the structure in The author also states that is less readable than Then there's the ending passage:> we hope that the introduced complexity is justified by the data readability expressed this way.
I cannot force myself to read this post as anything but a very poor Befungesque joke.
I’ve seen dozens of attempts to make S-Exp “better” even the original M-Exp. I also did some experiments myself. But at the end, I come back to goo’ol s-exp. Seems to be a maximum (or minimum) found just perchance.
https://docs.racket-lang.org/2d/
It might even be easier to treat the input string as a 2D grid than as a sequence and have a parsing head that behaves like a 2x2 convolutional kernel...
This would make for either a great Advent of Code, or a nightmare interview question, I love it.
Blocks are parsed in the following way: when we get the beginning count of block opening characters, we move Y by one, loop right while whitespace, until we encounter ending count of block characters.
In transposed block, we just switch X and Y, it is easily done with pointers, and use the same code.
With a vertical script like japanese you could easily rotate the whole program 90 degrees to the right (as shown at the bottom of the landing page)
https://web.archive.org/web/20240904091932/https://lookalive...
I kind of want something like, to borrow JSON-like syntax and gloss over namespacing issues:
...which would be another way to say (foo bar baz quuz), but would make it possible to represent any data structure you like at the same level as atoms, strings, and lists.You can have vectors, hash maps, and sets in addition to lists, symbols, and keywords.
Deleted Comment
Klisp (essentially complete implementation of Kernel): https://github.com/dbohdan/klisp