3 ms·

Understanding-j: An introduction to the J programming language that gets to the

62 points by todsacerdoti 2y ago

prezjordan 2y ago
To the author: you can add a .devcontainer directory with a Dockerfile, allowing folks to try this in their browser with GitHub Codespaces Shameless plug, feel free to copy my setup! https://github.com/jdan/try-j https://github.com/jdan/try-j
userbinator 2y ago
Unintentional humour with how the title got cut off?
pixelpoet 2y ago
The title stops just short of the
- johnisgood 2y ago
  "to the point", I presume, based on its README.
- pjmlp 2y ago
  A side effect of the small length available for titles and the whole titles should not be editoralised point of view.
  - Jtsummers 2y ago
    It's more an issue of todsacerdoti not checking their submission titles will fit, they do this a lot with their submissions. Abbreviating titles is not frowned upon when they don't fit, I've never had any reverted to something like this submission's title because I (for instance) shortened "United States" to "US" to shave off 11 characters. In this case, cutting out the superfluous "programming language" part would get you "Understanding-j: An introduction to J that gets to the point" which would fit just fine. When in doubt, include the original title in a comment to explain the edit and let the mods sort it out later.
    - detaro 2y ago
      It's hard to check if titles fit if you use a bot to repost from other sites.
      - Jtsummers 2y ago
        Fair, they're lazy and can't be bothered to fix their bot even after 5 years of submitting messed up titles.
t-writescode 2y ago
From the doc, _3 NB. negative numbers start with underscore _ NB. sole underscore is infinity: a number __ NB. negative infinity Is this a standard I'm unaware of?
- avmich 2y ago
  The use of underscore for negative numbers is J's choice, explained e.g. here - https://www.jsoftware.com/docs/help807/jforc/preliminaries.htm#_Toc191734298 https://www.jsoftware.com/docs/help807/jforc/preliminaries.h... . Explicitly representing infinity, and working with it in some cases, allows to reduce number of exceptions...
- Avshalom 2y ago
  APL used ¯3 for negative 3; J went underscore to be similar but ascii.
gitroom 2y ago
Underscore stuff always throws me off - never quite got used to how J does it. Gotta respect the weird choices though.
jbverschoor 2y ago
Not the same as (Visual) J++. Great IDE btw
vintagedave 2y ago
I’ve recently come to be fascinated by J. Twenty years ago, studying my computing degree, one semester we learned J. It was unlike anything I’d used before and the entire class found it confusing. The compiler / environment was reportedly written by one of the professors and it was routine to run into bugs; I remember puzzling through something, going to a tutor, and them just shrugging it off as a J interpreter issue. I never grokked it and simply passed the course. But it keeps on recurring to me and I pause to think of J at the weirdest times. As I use more and more languages, I’ve become more fascinated by it. Just like Prolog (also one semester, but with a reliable environment.) I want to learn both better.
binary132 2y ago
I’ve been thinking for the past couple of years that the ideal programming language would be something like a combination of a concatenative language (a la FORTH) and an array programming language.
- gnubison 2y ago
  Uiua?
  - binary132 2y ago
    interesting, I have not seen this one
preguntador 2y ago
12j34 is 12j + 34 or 12 + 34j?
- quartern 2y ago
  12 + 34j as per https://code.jsoftware.com/wiki/Vocabulary/Constants#Complex_.28j.29 https://code.jsoftware.com/wiki/Vocabulary/Constants#Complex...

62 points by todsacerdoti 2y ago

To the author: you can add a .devcontainer directory with a Dockerfile, allowing folks to try this in their browser with GitHub Codespaces Shameless plug, feel free to copy my setup! https://github.com/jdan/try-j https://github.com/jdan/try-j

userbinator 2y ago

Unintentional humour with how the title got cut off?

pixelpoet 2y ago

The title stops just short of the

johnisgood 2y ago
"to the point", I presume, based on its README.
pjmlp 2y ago
A side effect of the small length available for titles and the whole titles should not be editoralised point of view.
- Jtsummers 2y ago
  It's more an issue of todsacerdoti not checking their submission titles will fit, they do this a lot with their submissions. Abbreviating titles is not frowned upon when they don't fit, I've never had any reverted to something like this submission's title because I (for instance) shortened "United States" to "US" to shave off 11 characters. In this case, cutting out the superfluous "programming language" part would get you "Understanding-j: An introduction to J that gets to the point" which would fit just fine. When in doubt, include the original title in a comment to explain the edit and let the mods sort it out later.
  - detaro 2y ago
    It's hard to check if titles fit if you use a bot to repost from other sites.
    - Jtsummers 2y ago
      Fair, they're lazy and can't be bothered to fix their bot even after 5 years of submitting messed up titles.

t-writescode 2y ago

From the doc, _3 NB. negative numbers start with underscore _ NB. sole underscore is infinity: a number __ NB. negative infinity Is this a standard I'm unaware of?

avmich 2y ago
The use of underscore for negative numbers is J's choice, explained e.g. here - https://www.jsoftware.com/docs/help807/jforc/preliminaries.htm#_Toc191734298 https://www.jsoftware.com/docs/help807/jforc/preliminaries.h... . Explicitly representing infinity, and working with it in some cases, allows to reduce number of exceptions...
Avshalom 2y ago
APL used ¯3 for negative 3; J went underscore to be similar but ascii.

gitroom 2y ago

Underscore stuff always throws me off - never quite got used to how J does it. Gotta respect the weird choices though.

jbverschoor 2y ago

Not the same as (Visual) J++. Great IDE btw

vintagedave 2y ago

I’ve recently come to be fascinated by J. Twenty years ago, studying my computing degree, one semester we learned J. It was unlike anything I’d used before and the entire class found it confusing. The compiler / environment was reportedly written by one of the professors and it was routine to run into bugs; I remember puzzling through something, going to a tutor, and them just shrugging it off as a J interpreter issue. I never grokked it and simply passed the course. But it keeps on recurring to me and I pause to think of J at the weirdest times. As I use more and more languages, I’ve become more fascinated by it. Just like Prolog (also one semester, but with a reliable environment.) I want to learn both better.

binary132 2y ago

I’ve been thinking for the past couple of years that the ideal programming language would be something like a combination of a concatenative language (a la FORTH) and an array programming language.

gnubison 2y ago
Uiua?
- binary132 2y ago
  interesting, I have not seen this one

preguntador 2y ago

12j34 is 12j + 34 or 12 + 34j?

quartern 2y ago
12 + 34j as per https://code.jsoftware.com/wiki/Vocabulary/Constants#Complex_.28j.29 https://code.jsoftware.com/wiki/Vocabulary/Constants#Complex...