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Ken Iverson: Difference between revisions
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While the Iverson bracket was adopted into mainstream mathematics, it's use has not been very widespread. Donald Knuth has argued strongly for its wider use. | While the Iverson bracket was adopted into mainstream mathematics, it's use has not been very widespread. Donald Knuth has argued strongly for its wider use. | ||
In APL, the Iverson bracket is implied in all logical propositions, for example <syntaxhighlight lang=apl inline>4≥3</ | In APL, the Iverson bracket is implied in all logical propositions, for example <syntaxhighlight lang=apl inline>4≥3</syntaxhighlight> evaluates to <syntaxhighlight lang=apl inline>1</syntaxhighlight> and <syntaxhighlight lang=apl inline>'hello'≡'world'</syntaxhighlight> evaluates to <syntaxhighlight lang=apl inline>0</syntaxhighlight>. | ||
== Naming things == | |||
Iverson's work on programming languages sometimes crossed over with his studies of the English language. [[Roger Hui]] recounts that "Ken was deeply interested in words, their use and their etymology. He indeed did read the dictionary, and kept a copy of the [[wikipedia:The American Heritage Dictionary of the English Language|American Heritage Dictionary]] (along with other dictionaries) by his easy chair for ready reference."<ref>[[Roger Hui]]. [https://keiapl.org/rhui/remember.htm Remembering Ken Iverson]. 2004-11.</ref> Iverson also remarked on an interest in etymology among early APLers at [[IBM]].<ref>[[Roger Hui]]. "APL Quotations and Anecdotes", [https://www.jsoftware.com/papers/APLQA.htm#from_everywhere quoting Iverson].</ref> He chose names for APL concepts carefully and sometimes relied on obscure meanings, for example "[[ravel]]" in the sense of unmaking a knitted fabric<ref>[[Gitte Christensen]]. [http://archive.vector.org.uk/art10002270 Ken Iverson in Denmark]. [[Vector Journal]] volume 22 issue 3.</ref> and [[nub]] meaning the essential part. A suggestion of "coadunate representation" regarding [[wikipedia:reference counting|reference counting]] in [[SHARP APL]]<ref>[[Bob Bernecky]]. [https://dl.acm.org/doi/10.1145/390007.805333 Representations for enclosed arrays] at [[APL81]].</ref> was changed to "joint representation" by the time the feature was implemented.<ref>[[Leslie Goldsmith]]. "New Release of SHARP APL". IPSA Newsletter November/December 1982 ([https://www.snakeisland.com/IPSANewsletter_1982_11_12.pdf pdf])</ref> In [[A Dictionary of APL]], Iverson began to describe programming syntax in terms of English grammar, a choice that carried through to [[J]]—implementer Hui shared and encouraged Iverson's interest in English. | |||
[[The name APL]] was chosen by [[Adin Falkoff]] and not Iverson, albeit based on his [[A Programming Language]]. However, some of Iverson's names have become accepted in mainstream mathematics or programming, such as "floor" and "ceiling" as mentioned above, and [[reduction]], which may have been named in part for how it reduces the argument's rank by one. It's possible that Iverson coined the term "bubble sort", as A Programming Language is the first publication known to use it.<ref>Owen Astrachan. [https://dl.acm.org/doi/10.1145/792548.611918 Bubble Sort: An Archaeological Algorithmic Analysis] ([https://users.cs.duke.edu/~ola/bubble/bubble.html web]). 2003-01-11.</ref><ref>[[Roger Hui]]. "APL Quotations and Anecdotes", [https://www.jsoftware.com/papers/APLQA.htm#bubble_sort on bubble sort].</ref> | |||
== Publications == | == Publications == | ||
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=== SHARP APL Technical Notes === | === SHARP APL Technical Notes === | ||
* SATN-36: [[Direct Definition]]. 1980-04-20. | * SATN-36: [[Direct definition (notation)|Direct Definition]]. 1980-04-20. | ||
* SATN-41: [https://www.jsoftware.com/papers/satn41.htm Composition and Enclosure]. 1981-06-20. | * SATN-41: [https://www.jsoftware.com/papers/satn41.htm Composition and Enclosure]. 1981-06-20. | ||
* SATN-42: [https://www.jsoftware.com/papers/satn42.htm Determinant-Like Functions Produced by the Dot-Operator]. 1982-04-01. | * SATN-42: [https://www.jsoftware.com/papers/satn42.htm Determinant-Like Functions Produced by the Dot-Operator]. 1982-04-01. | ||
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* [http://keiapl.org/ A Celebration of the life of Kenneth Eugene Iverson] (has many links to writings about Iverson) | * [http://keiapl.org/ A Celebration of the life of Kenneth Eugene Iverson] (has many links to writings about Iverson) | ||
== References == | |||
<references/> | |||
{{APL community}}{{DEFAULTSORT:Iverson, Ken}}[[Category:People]][[Category:Jsoftware employees]][[Category:I.P. Sharp Associates employees]][[Category:Designers]] | {{APL community}}{{DEFAULTSORT:Iverson, Ken}}[[Category:People]][[Category:Jsoftware employees]][[Category:I.P. Sharp Associates employees]][[Category:Designers]] | ||