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  1. Glossary of APL terms

Glossary of APL terms

APL literature includes many terms whose meanings, though rigorous, differ slightly from elsewhere. Terms used here but not defined follow normal usage or are defined at FOLDOC.

Term

Description

ambivalent

(or nomadic)(of a dyadic function) permitting its left argument to be elided.

array

data valued object of zero or more orthogonal dimensions in row-major order in which each item is a primitive scalar or another array.

define

create by lexical assignment or association or in an editor.

depth

(of an array) the number of levels of nesting.

derive

create by juxtaposition as a combination of more than one previously existing array, function or operator.

dyadic

accepting or requiring two arguments or operands: left and right; having valence of two.

empty

(of an array) having one or more dimensions of length zero.

function

primitive, defined or derived operation or mapping that takes zero, one (right) or two (left & right) array valued arguments and may return an array valued result.

matrix

(of a function) applying to matrices.

monadic

accepting or requiring one argument or operand; on the right for a function; on the left for an operator; having valence of one.

nested

(of an array) having one or more items or a prototype which is not a primitive scalar.

niladic

accepting no arguments; having valence of zero.

operator

primitive or defined operation or mapping that takes one (left) or two (left & right) function or array valued arguments (operands) and derives a function.

prototype

(of an array) the type of its first item.

rank

(of an array) number of dimensions.
(of a function) ranks of arguments to which it applies.

reduction

application of a function between the items of its right argument.

scalar

(of a function) applying to scalars.

shape

(of an array) length of each dimension.

simple

(of a scalar) a single primitive datum.
(of an array) composed entirely of primitive scalars.

strand

lexical juxtaposition of array valued names or expressions to form a larger, possibly nested, array.

type

(of an array) array of identical structure in which all numbers are zero and all characters are blanks.

valence

degree or number of arguments or operands of an operation.

vector

(of a function) applying to vectors.

workspace

area of computer memory containing arrays and defined &/or derived operations or a file containing a preserved binary image of such.

-- PhilLast 2009-08-11 14:50:14

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