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Comparison of APL dialects: Difference between revisions
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All APL dialects share core features, and at least the [[primitive]]s are [[Backwards compatibility|backwards compatible]] with those of [[APL.SV]]. However, there are important dialectal differences, the most significant of which are described in this article. | |||
== Flat | == Flat versus Nested == | ||
One of the most significant differences between APLs is the choice of [[Nested array theory|nested]] or [[Flat array theory|flat]] | One of the most significant differences between APLs is the choice of [[array model]], namely [[Nested array theory|nested]] or [[Flat array theory|flat]]. Originally, all APLs were entirely flat, that is, the only [[scalar]] values supported were [[simple]] and had to be either [[number]]s and [[character]]s, and an array had to be homogeneous, that is, consisting entirely of a single [[type]]. [[SHARP APL]] introduced the [[box]] as a third type, such that a box could hold any other array (including a box array), and this allowed for arrays contain other arrays. [[NARS]] introduced the nested array model, where any arrays can be an actual [[element]] of another array. Most currently maintained dialects ([[Dyalog APL]], [[NARS2000]], [[APL2]], [[GNU APL]], and others) use the nested array model. | ||
== Complex numbers == | == Complex numbers == | ||
Most dialects support [[complex number]]s, but some ([[dzaima/APL]], [[APLX]], [[APL+Win]]) don't. Dialects with complex numbers also extend [[Circular]] (<syntaxhighlight lang=apl inline>○</syntaxhighlight>) to left arguments designed for complex numbers. | |||
== First/Mix == | == First/Mix == | ||
[[ | In dialects implementing [[nested array theory]], the two [[glyph]]s commonly used for [[Disclose]] are [[Right Shoe]] (<syntaxhighlight lang=apl inline>⊃</syntaxhighlight>) and [[Up Arrow]] (<syntaxhighlight lang=apl inline>↑</syntaxhighlight>). The original [[NARS]] paper specified [[monadic]] <syntaxhighlight lang=apl inline>↑</syntaxhighlight> as [[Mix]] and <syntaxhighlight lang=apl inline>⊃</syntaxhighlight> as [[First]], so [[Dyalog]] and [[STSC]] implemented [[Dyalog APL]] and [[APL*PLUS]] accordingly. [[IBM]] decided to swap them in [[APL2]], causing the others to implement [[Migration Level]], as APL2 was seen as the authoritative implementation. When the ISO [[standard]] was written, it closely followed APL2, causing [[APLX]], [[NARS2000]], [[GNU APL]], and [[ngn/apl]] to adopt these notations. However, ngn/apl later switched to follow Dyalog. | ||
== Depth == | == Depth == | ||
[[Dyalog APL]] defines [[Depth]] to return negative numbers when the depth | [[Dyalog APL]] defines [[Depth]] (<syntaxhighlight lang=apl inline>≡</syntaxhighlight>) to return negative numbers when the depth is uneven. Most other dialects instead define it to return the maximum depth. The original NARS paper assigned the glyph to a function called [[Simple (NARS)|Simple]], which simply answered if the argument was simple or not, without reporting the actual depth. It was thus equivalent to today's <syntaxhighlight lang=apl inline>1=≡,Y</syntaxhighlight>. | ||
== | == External links == | ||
* [https://omnibar.rubenverg.com Omnibar] is a site that lists all available glyphs in a variety of dialects together with their meanings. It supports filtering using set operations (union, intersection, difference) between feature sets of the supported dialects. | |||
[https://omnibar.rubenverg.com Omnibar] is a site that lists all available glyphs in | {{APL dialects}}[[Category:Lists]] | ||