; BY
;---------------------------------------------------------------
;! gives increment to use in FOR loops in POPS language
;# Verb POPS
;-----------------------------------------------------------------------
;;  Copyright (C) 1995
;;  Associated Universities, Inc. Washington DC, USA.
;;
;;  This program is free software; you can redistribute it and/or
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;;  published by the Free Software Foundation; either version 2 of
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;;
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;;  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;  GNU General Public License for more details.
;;
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;;  License along with this program; if not, write to the Free
;;  Software Foundation, Inc., 675 Massachusetts Ave, Cambridge,
;;  MA 02139, USA.
;;
;;  Correspondence concerning AIPS should be addressed as follows:
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;;         Postal address: AIPS Project Office
;;                         National Radio Astronomy Observatory
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;-----------------------------------------------------------------------
;---------------------------------------------------------------
BY        LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC
----------------------------------------------------------------
BY
Type:  Verb
Use:   In the FOR loop construction BY is used to signal the
       value by which to increment the incrementing variable.
       (See HELP FOR).  This value may be negative. The
       inclusion of BY is optional. If omitted, the increment
       will default to 1.
Grammar:  FOR variable = start TO fini BY increment
             statement1; statement2;... ; END
       where 'variable' is a scalar variable that will change
       each time through the loop, beginning at 'start', have
       'increment' added to it each time through the loop (the
       increment may be positive or negative) and will end when
       the next loop would be executed with 'variable' greater
       than (increment > 0; less than with increment < 0)
       'fini'.  Note that the loop will be executed at least
       once no matter what the start, fini and increment
       parameters are. If the BY section is omitted, the
       increment will default to 1.  Statementi are AIPS
       statements.
Example:   FOR I = K+3 TO K BY -1; A(I+1) = A(I); END
       This example will shift the section of array A between
       A(K) and A(K+3) forward 1 element.
----------------------------------------------------------------
