data_jd VS jsource

I suspect the J package Jd is probably the most non-trivial public codebase. I don’t love the coding style (functions are long and scripted) and it doesn’t make use of newer lambda functions (“direct definitions”) which are easier to read. https://github.com/jsoftware/data_jd

An example J file because this link doesn't say much:

https://github.com/jsoftware/data_jd/blob/master/csv/csv.ijs

Here's one of the more central files that ties into how a Jd database is laid out:

https://github.com/jsoftware/data_jd/blob/master/base/common...

Not that I claim anyone in particular can read it of course. Jd uses a hierarchy of folder, database, table, column that's handled with an object system to share code between them. A folder is just a place to put databases and hardly needs to add anything, while the other levels have a lot of extra functionality. As an inverted database, Jd stores each column in a file, and accesses it using memory mapping.

https://github.com/jsoftware/data_jd/blob/master/base/folder...

https://github.com/jsoftware/data_jd/blob/master/base/table....

(I designed this system when I did some of the early work to turn JDB into Jd as a summer intern)

I found this license for jd itself. It is free only for non-commercial use:

https://github.com/jsoftware/data_jd/blob/master/doc/License...

The link you mentioned only applies to the jsource folder: the jengine code.

A longer piece from GitHub: csvreportsummary=: 3 : 0 t=. <;.2 fread PATHLOGLOGFILE b=. (<,LF)=t b=. b+.(<'!')={.each t b=. b+.(<'src: ')=5{.each t b=. b+.(<'snk: ')=5{.each t b=. b+.(<'elapsed: ')=9{.each t b=. b+.(<'rows: ')=6{.each t b=. b+.(<'error: ')=7{.each t ;b#t )

No, it was rhetorical, because it's obviously (to an APL-family programmer), not bad!

Your cultural prejudice is showing. There are good reasons APL is written the way it is, and this example is simply bringing those benefits to C by writing it in the dense APL style. There are other APL derivatives, like J[1] that are written the same way. These projects are well-maintained. They aren't collapsing under a load of technical debt. The style works. To them, it's clean code.

[1]: https://github.com/jsoftware/jsource

You can view the code, but is not open source: https://github.com/jsoftware/jsource/blob/master/license.txt

This is the same dense style used in J.

All-in-all this example doesn't seem too bad. It's clear what happens and is easy to follow. If you wan't to see something remarkably terribly, check out Whitney style. It's used in APL/J/K family interpreters. Keep in mind, financial institutions run that code.

good first issue

Looking at the j source code, this might fall under the rule against posting crazy people.

The original header defining the signatures (somewhat cryptically): https://github.com/jsoftware/jsource/blob/master/jsrc/jlib.h