

                                                                      mask

    FUNCTION
MASK MONOTONIC-INDICES                                           [Function]

    Package
    series

    DESCRIPTION

MASK is a quasi-inverse of POSITIONS.  The series input MONOTONIC-INDICES
must be a strictly increasing series of non-negative integers.  The output,
which is always unbounded, contains T in the positions specified by
MONOTONIC-INDICES and NIL everywhere else.

(MASK #Z()) => #Z(NIL NIL ...) 
(MASK #Z(0 2 3)) => #Z(T NIL T T NIL NIL ...) 
(MASK (POSITIONS #Z(NIL A NIL B NIL))) => #Z(NIL T NIL T NIL ...)


     SEE ALSO
     about-series
     about-generators
     positions

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