Fold and Other Functional Conjunctions
The Array Cast
Fold in a J Application
Fold is a conjunction in which in J means it takes two verbs as its arguments so you say you fold V and that combination defines a verb. It's just the latest in a long line of things that APL is added to do useful stuff. If there's no bugs, Fold will eventually be migrated into native C code but it should be part of the standard installed now.
Array Cast - March 31, 2023
Show Notes
Thanks to Bob Therriault, Conor Hoekstra and Marshall Lochbaum for gathering these links:
[01] 00:01:45 Luther J. Woodrum Obituary https://www.fraryfuneralhome.com/obituaries/Luther--J.-Woodrum?obId=27482014#/celebrationWall
https://www.linkedin.com/in/luther-woodrum-b5775a4a?trk=public_profile_browsemap
Lenore Mullin Mathematics of Arrays https://www.linkedin.com/in/lenore-mullin-268b0a13
[02] 00:03:46 Episode 6 https://www.arraycast.com/episodes/episode-06-henry-richs-deep-dive-into-j
Episode 18 https://www.arraycast.com/episodes/episode18-henry-rich-presents-j903
Episode 48 https://www.arraycast.com/episodes/episode48-henry-rich
[03] 00:04:40 Command to run Fold using J Playground - install 'github:jsoftware/dev_fold'
J Fold https://code.jsoftware.com/wiki/Vocabulary/fcap
APL Reduce / https://aplwiki.com/wiki/Reduce
APL Scan \ https://aplwiki.com/wiki/Scan
J Scan /\ https://code.jsoftware.com/wiki/Vocabulary/bslash
https://code.jsoftware.com/wiki/Vocabulary/slash
J Grade /: or \: https://code.jsoftware.com/wiki/Vocabulary/slashco
[04] 00:10:02 Functional Programming Language https://en.wikipedia.org/wiki/Functional_programming
C Programming Language https://en.wikipedia.org/wiki/C_(programming_language)
[05] 00:12:30 Iverson Notation https://www.jsoftware.com/papers/APL.htm
Adjacent Difference C++ https://en.cppreference.com/w/cpp/algorithm/adjacent_difference
[06] 00:14:50 Haskell Programming Language https://en.wikipedia.org/wiki/Haskell
BQN Primitives https://mlochbaum.github.io/BQN/commentary/primitive.html
[07] 00:16:10 Object Oriented Programming https://en.wikipedia.org/wiki/Object-oriented_programming
[08] 00:17:12 J Power Conjunction u^:n https://code.jsoftware.com/wiki/Vocabulary/hatco
NARS 2000 APL https://aplwiki.com/wiki/NARS
J Rank Conjunction " https://code.jsoftware.com/wiki/Vocabulary/quote
J Cut Conjunction ;. https://code.jsoftware.com/wiki/Vocabulary/semidot
J Key Conjunction /. https://code.jsoftware.com/wiki/Vocabulary/slashdot#dyadic
J Recursion $: https://code.jsoftware.com/wiki/Vocabulary/dollarco
[09] 00:24:20 Identity Element https://aplwiki.com/wiki/Identity_element
[10] 00:37:09 J Terminate Z: https://code.jsoftware.com/wiki/Vocabulary/zcapco
J Cap [: https://code.jsoftware.com/wiki/Vocabulary/squarelfco
[11] 00:41:22 J throw. https://code.jsoftware.com/wiki/Vocabulary/throwdot
J catch. https://code.jsoftware.com/wiki/Vocabulary/trydot
[12] 00:45:21 J ^:v^:_ https://code.jsoftware.com/wiki/Vocabulary/hatco#DoWhile
J _3 Z: (Iterations bottom of page) https://code.jsoftware.com/wiki/Vocabulary/zcapco
[13] 00:53:05 BQN Fold https://mlochbaum.github.io/BQN/doc/fold.html
Table from J Fold to K https://code.jsoftware.com/wiki/User:Will_Gajate/FoldVariants
[14] 00:55:13 Arthur Whitney https://en.wikipedia.org/wiki/Arthur_Whitney_(computer_scientist)
APL Partition https://aplwiki.com/wiki/Partition
[15] 00:57:55 J Gerunds https://code.jsoftware.com/wiki/Vocabulary/Glossary#Gerund
[16] 00:59:20 J Rank-Gerund 901 Release Notes https://code.jsoftware.com/wiki/System/ReleaseNotes/J901
[17] 01:01:11 C++ 2019 7 Consecutive Ones Conor talk https://www.youtube.com/watch?v=48gV1SNm3WA
[18] 01:03:10 BQN Each https://mlochbaum.github.io/BQN/doc/map.html
[19] 01:05:25 Dyalog APL Split https://aplwiki.com/wiki/Split
APL2 https://aplwiki.com/wiki/APL2
[20] 01:07:42 J NuVoc Dictionary https://code.jsoftware.com/wiki/NuVoc
[21] 01:11:25 Index Origin https://aplwiki.com/wiki/Index_origin
[22] 01:27:15 CPU Cache https://en.wikipedia.org/wiki/CPU_cache
[23] 01:33:00 ValGrind Tool https://valgrind.org/docs/manual/
Perf linux https://perf.wiki.kernel.org/index.php/Tutorial
[24] 01:35:58 Contact AT ArrayCast DOT Com
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