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{{Glyphbox|∘}}
{{Glyphbox|∘}}
The [[glyph]] '''jot''' is a small circle represented by the [[Unicode]] character <code>∘</code>, "ring operator" (<code>◦</code>, "white bullet", may also be used in some dialects). Derived from the [[Iverson notation]] convention of using a circle for the top (reducing) function of an [[Inner Product]] to turn it into an [[Outer Product]], the jot now has several uses in various dialects:
The [[glyph]] '''jot''' is a small circle represented by the [[Unicode]] character <code>∘</code>, "ring operator" (<code>◦</code>, "white bullet", may also be used in some dialects). Derived from the [[Iverson notation]] convention of using a circle for the top (reducing) function of an [[Inner Product]] to turn it into an [[Outer Product]], the jot now has several uses in various dialects:
* In [[APL\360]] and all other APLs, it is a "special" left operand to [[Inner Product]] (<source lang=apl inline>.</source>), so that (<source lang=apl inline>∘.f</source>) is an [[Outer Product]] by <source lang=apl inline>f</source>.
* In [[APL\360]] and all other APLs, it is a "special" left operand to [[Inner Product]] (<syntaxhighlight lang=apl inline>.</syntaxhighlight>), so that (<syntaxhighlight lang=apl inline>∘.f</syntaxhighlight>) is an [[Outer Product]] by <syntaxhighlight lang=apl inline>f</syntaxhighlight>.
* In [[SHARP APL]], <source lang=apl inline>∘</source>, named [[nil]], is the [[enclose]]d [[empty]] [[numeric]] [[vector]], which may also be written <source lang=apl inline><⍳0</source>.
* In [[SHARP APL]], <syntaxhighlight lang=apl inline>∘</syntaxhighlight>, named [[nil]], is the [[enclose]]d [[empty]] [[numeric]] [[vector]], which may also be written <syntaxhighlight lang=apl inline><⍳0</syntaxhighlight>.
* In [[NARS]], [[Dyalog APL]], and other [[Nested array model|nested]] APLs derived from these, <source lang=apl inline>∘</source> is the [[Compose]] [[operator]].
* In [[NARS]], [[Dyalog APL]], and other [[Nested array model|nested]] APLs derived from these, <syntaxhighlight lang=apl inline>∘</syntaxhighlight> is the [[Compose]] [[operator]].
* In [[NARS]] and [[NARS2000]], for an array <source lang=apl inline>a</source>, <source lang=apl inline>a∘/</source> is [[Mask]] and <source lang=apl inline>a∘\</source> is [[Mesh]].
* In [[NARS]] and [[NARS2000]], for an array <syntaxhighlight lang=apl inline>a</syntaxhighlight>, <syntaxhighlight lang=apl inline>a∘/</syntaxhighlight> is [[Mask]] and <syntaxhighlight lang=apl inline>a∘\</syntaxhighlight> is [[Mesh]].
Thus jot may be considered either a special element of syntax as in [[APL\360]], an [[array]] as in [[SHARP APL]], or an [[operator]]. In the last case it would not normally be allowed as an [[operand]] to the [[Inner Product]] operator, and a special rule is needed to allow the [[Outer Product]] syntax. As a final option, [[APL2]] allows a jot only in the context of an Outer Product like APL\360, but documents that jot "is treated syntactically as a [[function]]."<ref>[[IBM]]. [https://www.ibm.com/downloads/cas/ZOKMYKOY "APL2 Programming: Language Reference"]. 1994. p.24.</ref>
Thus jot may be considered either a special element of syntax as in [[APL\360]], an [[array]] as in [[SHARP APL]], or an [[operator]]. In the last case it would not normally be allowed as an [[operand]] to the [[Inner Product]] operator, and a special rule is needed to allow the [[Outer Product]] syntax. As a final option, [[APL2]] allows a jot only in the context of an Outer Product like APL\360, but documents that jot "is treated syntactically as a [[function]]."<ref>[[IBM]]. [https://www.ibm.com/downloads/cas/ZOKMYKOY "APL2 Programming: Language Reference"]. 1994. p.24.</ref>



Latest revision as of 22:15, 10 September 2022

The glyph jot is a small circle represented by the Unicode character , "ring operator" (, "white bullet", may also be used in some dialects). Derived from the Iverson notation convention of using a circle for the top (reducing) function of an Inner Product to turn it into an Outer Product, the jot now has several uses in various dialects:

Thus jot may be considered either a special element of syntax as in APL\360, an array as in SHARP APL, or an operator. In the last case it would not normally be allowed as an operand to the Inner Product operator, and a special rule is needed to allow the Outer Product syntax. As a final option, APL2 allows a jot only in the context of an Outer Product like APL\360, but documents that jot "is treated syntactically as a function."[1]

References

APL glyphs [edit]
Information GlyphTyping glyphs (on Linux) ∙ UnicodeFontsMnemonicsOverstrikesMigration level
Individual glyphs Jot () ∙ Right Shoe () ∙ Up Arrow () ∙ Zilde () ∙ High minus (¯) ∙ Dot (.) ∙ Del ()