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{{Built-in|Disclose|⊃}} or '''Reveal''' is a [[monadic function]] in [[Nested array model|nested]] APLs which reduces the level of nesting of an array. Early experiments in array nesting usually defined a primitive to extract the contents of a nested [[scalar]], but did not always specify how it should behave on an array. [[Jim Brown]]'s "A Generalization of APL",<ref>[[Jim Brown]]. [http://www.softwarepreservation.org/projects/apl/Books/AGENERALIZATIONOFAPL "A Generalization of APL"] (Ph.D. thesis). 1971.</ref> stated that it "may be undefined" on non-scalar arrays. However, all dialects do define it on non-scalars, but with differing definitions. Some dialects, for example [[Dyalog APL]], have it extract the argument's initial element in [[ravel order]], while others, for example [[APL2]] have it combine the array's elements (requiring conforming shapes or padding with [[fill element]]s). Depending on which approach is taken, it is recommended to use the unambiguous names [[First]] and [[Mix]] for these two functions.
{{Built-in|Disclose|⊃}} or '''Reveal''' is a [[monadic function]] in [[Nested array model|nested]] APLs which reduces the level of nesting of an array. It may refer to:
 
* [[First]], a the function extracting its argument's initial element in [[ravel order]].
* [[Mix]], a function combining its argument's elements (requiring conforming shapes or padding with [[fill element]]s).
 
Early experiments in array nesting usually defined a primitive to extract the contents of a nested [[scalar]], but did not always specify how it should behave on an array. [[Jim Brown]]'s "A Generalization of APL",<ref>[[Jim Brown]]. [http://www.softwarepreservation.org/projects/apl/Books/AGENERALIZATIONOFAPL "A Generalization of APL"] (Ph.D. thesis). 1971.</ref> stated that it "may be undefined" on non-scalar arrays. However, all dialects do define it on non-scalars, but with differing definitions.


For a discussion of all uses of the [[glyph]] <code>⊃</code>, see [[Right Shoe]].
== References ==
== References ==
<references/>
<references/>
{{APL built-ins}}[[Category:Primitive functions]]
{{APL built-ins}}[[Category:Primitive functions]]

Revision as of 12:46, 1 May 2020

⊃

Disclose (⊃) or Reveal is a monadic function in nested APLs which reduces the level of nesting of an array. It may refer to:

  • First, a the function extracting its argument's initial element in ravel order.
  • Mix, a function combining its argument's elements (requiring conforming shapes or padding with fill elements).

Early experiments in array nesting usually defined a primitive to extract the contents of a nested scalar, but did not always specify how it should behave on an array. Jim Brown's "A Generalization of APL",[1] stated that it "may be undefined" on non-scalar arrays. However, all dialects do define it on non-scalars, but with differing definitions.

References

  1. ↑ Jim Brown. "A Generalization of APL" (Ph.D. thesis). 1971.
APL built-ins [edit]
Primitives (Timeline) Functions
Scalar
Monadic Conjugate ∙ Negate ∙ Signum ∙ Reciprocal ∙ Magnitude ∙ Exponential ∙ Natural Logarithm ∙ Floor ∙ Ceiling ∙ Factorial ∙ Not ∙ Pi Times ∙ Roll ∙ Type ∙ Imaginary ∙ Square Root
Dyadic Add ∙ Subtract ∙ Times ∙ Divide ∙ Residue ∙ Power ∙ Logarithm ∙ Minimum ∙ Maximum ∙ Binomial ∙ Comparison functions ∙ Boolean functions (And, Or, Nand, Nor) ∙ GCD ∙ LCM ∙ Circular ∙ Complex ∙ Root
Non-Scalar
Structural Shape ∙ Reshape ∙ Tally ∙ Depth ∙ Ravel ∙ Enlist ∙ Table ∙ Catenate ∙ Reverse ∙ Rotate ∙ Transpose ∙ Raze ∙ Mix ∙ Split ∙ Enclose ∙ Nest ∙ Cut (K) ∙ Pair ∙ Link ∙ Partitioned Enclose ∙ Partition
Selection First ∙ Pick ∙ Take ∙ Drop ∙ Unique ∙ Identity ∙ Stop ∙ Select ∙ Replicate ∙ Expand ∙ Set functions (Intersection ∙ Union ∙ Without) ∙ Bracket indexing ∙ Index ∙ Cartesian Product ∙ Sort
Selector Index generator ∙ Grade ∙ Index Of ∙ Interval Index ∙ Indices ∙ Deal ∙ Prefix and suffix vectors
Computational Match ∙ Not Match ∙ Membership ∙ Find ∙ Nub Sieve ∙ Encode ∙ Decode ∙ Matrix Inverse ∙ Matrix Divide ∙ Format ∙ Execute ∙ Materialise ∙ Range
Operators Monadic Each ∙ Commute ∙ Constant ∙ Replicate ∙ Expand ∙ Reduce ∙ Windowed Reduce ∙ Scan ∙ Outer Product ∙ Key ∙ I-Beam ∙ Spawn ∙ Function axis
Dyadic Bind ∙ Compositions (Compose, Reverse Compose, Beside, Withe, Atop, Over) ∙ Inner Product ∙ Determinant ∙ Power ∙ At ∙ Under ∙ Rank ∙ Depth ∙ Variant ∙ Stencil ∙ Cut ∙ Direct definition (operator)
Quad names Index origin ∙ Comparison tolerance ∙ Migration level ∙ Atomic vector
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