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ZONE pre-process v1.1 |
Pipelines v2.1 |
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Syntax |
>>──stage──ZONE(─┬────────────┬──┬───────┬──┬─────────┬─)──┬──────────┬──────────────><
└─inputrange─┘ └─CASEI─┘ └─REVerse─┘ └─operands─┘
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Purpose |
Use the ZONE pre-process function to alter
the input records read by the stage
from any of its input streams. The ZONE function operates on the input records
before they are presented to the stage.
There are a number of stages that permit
the use of the ZONE function and these are stages that do not perform any
translation of their input records. They are purely filter type stages that
simply select input records based on some criteria.
The ZONE function instructs the manager to
extract a substring of the record, determined by the column, word or field
range, and optionally; to translate both the stage operands and the content of the input records to uppercase,
and present this altered record to the stage
when a read-record is requested. The ZONE function does not alter the way
in which a stage processes its input and output records, it only
alters the format of the record which is presented to the stage. When the stage performs a subsequent write-record request,
the manager writes the original unmodified input record to the specified output
stream.
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Operands |
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Streams |
None.
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Usage |
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1. |
You
cannot specify the ZONE pre-process function with a stage that does not support it. |
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2. |
The
CASEI function translates input records to uppercase before they are
presented to the stage. As such, if
the stage searches for a
hexadecimal or binary representation of a lowercase character; the stage will not find the character
because the input record has already be translated to uppercase, as in the
following example: **** Top of file ****1 Address Rxpipe 23 'pipe lit /aBbCc def ghi/', 4 '| split', 5 '| between zone( 3-* casei ) x62 /b/', 6 '| cons' 78 Exit 0 **** End of file ****
The lowercase b (x'62') in the literal string is not found because it was
translated to an uppercase B before
BETWEEN processed its input record. Similarly,
if the stage specifies a word or
field range with a word or field separator string in hexadecimal or binary
format, then the extracted range may not be as expected as the record
presented to the stage will have
been translated to uppercase. |
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3. |
Stages that allow the use of the ZONE
function do not delay the records. |
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Examples |
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1. |
In
the following example, the pipeline specifies only word number 2 as the input
location. 'pipe lit /a-B-c c-b-A/ | split | fromlab zone( wordsep /-/ w2 casei ) /b/ | cons'output:a-B-cc-b-A |
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2. |
The following pipeline specifies
the third-from-last to the second-from-last columns as the input location. 'pipe literal /ABCDE FGHIJ/ | split | tolabel zone( -3;-2 casei ) /hi/ | console'output:
ABCDE |
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3. |
The following example reads the file:
input.txt and selects records from
(and including) one that ends in two hyphens up to (and including) one that
ends in a full-stop (period), and writes its output to the file: output.txt. 'pipe
< input.txt | between zone(-2;-1 reverse) /--/ /./ | > output.txt' When the last character in a
record is a full-stop, ZONE reverses the period and the character preceding
it so BETWEEN can then find the records that begin with a period. |