Hyperpolyglot: Lisp | Hacker News Reader

Hyperpolyglot: Lisp

hyperpolyglot.org

127 pointstosh17 comments

This is not particularly accurate, and doesn't seem maintained. Just looking at the start of the first column, Common Lisp, for a bit:

- "command line program" is empty, but should contain

    sbcl --eval '(+ 1 1)'

- "identifier" says "case insensitive, cannot start with digit", but identifiers can start with digits just fine. 1+ is a built-in function that proves it. It just can't look like a number.

- "identifier" also says some characters are "reserved for user macros", but that's not actually a thing. ?![]{} is a valid identifier, you just shouldn't use it.

There's probably much more. There are also plenty of things that are inaccurate, but would need more explanation than there is room for.

https://github.com/clarkgrubb/hyperpolyglot/issues

I looked at that, which is why I mentioned it "doesn't seem maintained". Issues there are old and not getting responses and the last commit is from a year ago.

I noticed some weird and out of date stuff with Racket too.

I don't use racket much, and even I noticed some stuff that are off. Nobody really uses srfi-19 for dates (everybody recommends Gregor iirc) and they hardly seem to use any for loops.

I don't know if it's part of the spec, but sbcl is actually case-sensitive, just that read upcases everything by default. There's a special syntax if you need to preserve case:

    |this-will-be-read-with-case-preserved|

That's part of Common Lisp. By default the reader is case-insensitive and upcasing -> the internal representation is case-preserving. If we escape characters in a symbol or even the whole symbol, those preserve their case.

But one can for example configure the READER in Common Lisp to use different modes - for example fully case preserving. The built-in CL symbols will stay in uppercase - because that's how they are defined.

  CL-USER 32 > (setf (readtable-case *readtable*) :preserve)
  :PRESERVE

  CL-USER 33 > (DEFUN This-Is-A-Symbol (VarIable)
                 (SIN VarIable))
  This-Is-A-Symbol

  CL-USER 34 > (This-Is-A-Symbol 7.4)
  0.89870817

  CL-USER 35 > (THIS-IS-A-SYMBOL 7.4)

  Error: Undefined operator THIS-IS-A-SYMBOL in form (THIS-IS-A-SYMBOL 7.4).

As you can see, we can then program with case preserved syntax and use the uppercase built-in symbols like DEFUN or SIN.

That syntax is displayed lower down, under "quoted identifier". I think this is an area that "would need more explanation than there is room for". There's also the fact that |white space symbol| and white\ space\ symbol are not actually the same thing.

Right:

  CL-USER 26 > (defun ?![]{} (123456789?![]{})
                 (+ 123456789?![]{} #xd))
  ?![]{}

  CL-USER 27 > (?![]{} #x1d)
  42

Wow, that web page is a labor of love. Very cool! I feel like making wallpaper from it when I return home next year and I will need to re-furnish my study.

I don't understand why this is useful. What does the comparison provide to the hungry mind?

Towards understanding, I recommend reading SICP and "On Lisp"

I only know a bit of elisp and thought the other ones would seem more different and therefore more demanding for me to learn, but after looking through this comparison I feel I could well give one or two of the other a shot without too much work.

> #!/usr/bin/env java -jar clojure.jar

What's with the shebangs? They all have more than 1 argument. Where would that work? Not Linux. I think FreeBSD used to have support for that, but removed it to follow convention. Seems like stuff wasn't tested before publishing.

OSX/macOS, minix and for a time FreeBSD[0]

[0] https://www.in-ulm.de/~mascheck/various/shebang/ (See table near bottom)

Interesting. Does OSX include quoting or escaping logic or is it impossible to provide an argument that has spaces?

In the markup languages section, it's missing a lot of Org mode snippets. I'll see if there a way to contribute to that page. It's quite outdated.

> SBCL 1.2

This page seems not to have been updated in years. The newest SBCL version is 1.4.10; version 1.2.0 was released in 2014.

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