NAME
    test - whether a value is deemed to be true or false

SYNOPSIS
    test(x)

TYPES
    x		any

    return	0 or 1

DESCRIPTION
    This function returns 1 or 0 according as x tests as "true" or "false".

    Conditions under which a value x is considered to be false are:

	Numbers (real or complex):  x is zero

	String: x == ""

	Matrix: every component of x tests as false

        List: every element of x tests as false

        Association: x has no element

	File: x is not open

	Null: always

	Object of type xx: if xx_test has been defined, xx_test(x)
		returns zero;  if xx_test has not been defined,
		every element of x tests as false.

	Error-value or other types: never

EXAMPLE
	> print test(27), test(0), test("abc"), test("")
	1 0 1 0

	> print test(mat[3] = {1,,2}), test(mat[2][2])
	1 0

	> A = list(0, 2, 0)
	> print test(A), test(pop(A)), test(A), test(pop(A)), test(A)
	1 0 1 1 0

LIMITS
    none

LIBRARY
    none

SEE ALSO
    isassoc, isfile, isident, isnum, isint, islist, ismat, isnull, isobj,
    isreal, isstr, issimple, istype