removing-trailing-blank-records-3.rex

Pipelines v2.1

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 **** Top of file ****
 1
 2 /* The following pipeline reads the file: winston.txt and removes any trailing blank lines
 3 and displays the result on the console.
 4
 5 There are a number of ways of identifying and removing trailing blank lines, however,
 6 this pipeline construction demonstrates the fastest and most efficient method as it only
 7 joins and buffers a non blank line followed by consecutive blank lines (1 byte each)
 8 in order to isolate a set of trailing blank records. */
 9
 10 Address Rxpipe
 11
 12 'pipe (endchar ?)',
 13 '< &installdrive:\&installpath\examples\input\winston.txt',
 14 '| strip trailing', /* Trim off whitespace. */
 15 '| a: locate', /* Route out blank records. */
  16 '| specs xfe 1 1-* n', /* Insert a x'fe' in column 1. */
 17 '| split after str xfe', /* Split after the x'fe'. */
 18 '| b: faninany', /* Merge the streams. */
 19 '| join until 1 xfe', /* Collect blank records and join them to the end.. */
 20 , /* ..of the current non-blank record. */
 21 '| c: take last', /* Isolate the last record. */
 22 '| change xff //', /* Remove blank line indicators. This removes trailing.. */
 23 , /* ..whitespace from the end of the last record.. */
 24 ,  /* ..(where each x'ff' represents a trailing blank line!). */
 25 '| d: faninany', /* Merge the streams. */
 26 '| split before str xff', /* Split the records just before x'ff's */
 27 '| change xff //', /* Remove blank line indicators. */
 28 '| cons', /* Display on the console. */
 29 '?',
 30 'a:',
 31 '| specs xff 1', /* Mark a blank line with a x'ff' character. */
 32 '| b:', /* Route back to main pipeline. */
 33 '?',
 34 'c:',
 35 '| take *', /* Handle all but the last input record. */
 36 '| d:' /* Route back to main pipeline. */
 37
 38 Say 'Hit Enter to close..'
 39 Parse Pull
 40
 41 Exit 0
 **** End of file ****