2,954
edits
(→Documentation: BQN link) |
|||
(3 intermediate revisions by 2 users not shown) | |||
Line 1: | Line 1: | ||
{ | {| class=vertical-navbox style="float:right; font-size:500%; margin:0 1ex;" | ||
|<code>⊇</code> <code>@</code> | |||
|} | |||
'''From''' (<code>⊇</code> or <code>@</code> and also called '''Select''', or, [[humour]]ously, ''Sane Indexing'') is a [[primitive function]] that selects multiple [[major cell]]s of its right argument using an array of [[index|indices]] given by its left. The primitive often offers additional functionality for a [[nested]] left argument, which varies from one language to another. It appears in [[J]] (as <source lang=j inline>{</source>), [[Extended Dyalog APL]], [[dzaima/APL]], [[KAP]], and [[BQN]] (as <code>⊏</code>). | |||
== Common usage == | == Common usage == | ||
Line 38: | Line 41: | ||
== History == | == History == | ||
From (<code>{</code>) was introduced in 1986 by [[A Dictionary of APL]], with the same meaning now used in [[J]]. This description introduced the characteristic feature of selection of multiple cells simultaneously, as well as the pairing with monadic [[Catalogue]], scatter-point indexing, negative indices, and the ability to exclude rather than include indices using a third level of boxing. [[Roger Hui]] expressed his support for the new definition with a presentation at the next [[APL conference]]<ref>[[Roger Hui]]. [https://www.jsoftware.com/papers/from.htm Some Uses of { and }] at [[APL87]].</ref>, and it was included in J from the earliest drafts in 1990—a limited version had even appeared in [[Arthur Whitney]]'s one-page interpreter prototype. | From (<code>{</code>) was introduced in 1986 by [[A Dictionary of APL]], with the same meaning now used in [[J]]. This description introduced the characteristic feature of selection of multiple cells simultaneously, as well as the pairing with monadic [[Catalogue]], scatter-point indexing, negative indices, and the ability to exclude rather than include indices using a third level of boxing. [[Roger Hui]] expressed his support for the new definition with a presentation at the next [[APL conference]]<ref>[[Roger Hui]]. [https://www.jsoftware.com/papers/from.htm Some Uses of <code>{</code> and <code>}</code>] at [[APL87]].</ref>, and it was included in J from the earliest drafts in 1990—a limited version had even appeared in [[Arthur Whitney]]'s one-page interpreter prototype. | ||
[[SHARP APL]] followed A Dictionary of APL and used <code>{</code>, but this was later deprecated, programmers being told to use <code>@</code> instead.<ref>Soliton Associates Limited. SHARP APL for UNIX Language Guide. [https://abrudz.github.io/SAX2/SAX61.pdf#G41.16516 Deprecated Primitives: Braces]. 2000.</ref> | |||
The name Select and glyph <code>⊇</code> were introduced by [[Extended Dyalog APL]], and subsequently adopted by [[dzaima/APL]] and [[KAP]]. | The name Select and glyph <code>⊇</code> were introduced by [[Extended Dyalog APL]], and subsequently adopted by [[dzaima/APL]] and [[KAP]]. | ||
Line 53: | Line 58: | ||
* J: [https://www.jsoftware.com/help/dictionary/d520.htm Dictionary], [https://code.jsoftware.com/wiki/Vocabulary/curlylf#dyadic Nuvoc] | * J: [https://www.jsoftware.com/help/dictionary/d520.htm Dictionary], [https://code.jsoftware.com/wiki/Vocabulary/curlylf#dyadic Nuvoc] | ||
* [https://abrudz.github.io/SAX2/SAX61.pdf#M44.9.from SAX] | * [https://abrudz.github.io/SAX2/SAX61.pdf#M44.9.from SAX] | ||
* [https://mlochbaum.github.io/BQN/doc/select.html BQN] | |||
== References == | == References == | ||
<references/> | <references/> | ||
{{APL built-ins}}[[Category:Primitive functions]] | {{APL built-ins}}[[Category:Primitive functions]] |