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VARIABLE stage v1.1
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Pipelines v2.1
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Need
examples
Tracking needs a tool tip!
>>──VARiable──┬─name────────┬──┬──────────┬──────────────────────────────────────────><
├─name[index]─┤ └─TRACKing─┘
└─name.index──┘
Use the VARIABLE stage to
retrieve or set an ooRexx variable, array or stem entry.
By default, when
VARIABLE is the first stage of a pipeline; VARIABLE retrieves the value of an
ooRexx variable and writes the value to its primary output stream. When
VARIABLE is not the first stage of a pipeline, VARIABLE sets the specified
variable to the contents of the first record in its primary input stream and
then the VARIABLE stage terminates. If at termination; the VARIABLE stage
determines that no input records have been read and that the specified ooRexx
variable is a simple variable (not an array or stem entry); then the variable
is dropped, otherwise the specified array or stem entry remains unchanged.
VARIABLE also copies its primary input stream records to its primary output
stream.
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name
specifies the name of
the ooRexx variable, array or stem entry on which to operate.
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index
an unsigned integer which specifies the array or
stem index.
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TRACKing
specifies that VARIABLE, when
it is the first stage of a pipeline; continuously obtains the value of the variable
and writes it to the primary output stream. When VARIABLE is not the first
stage of a pipeline, TRACKING specifies that VARIABLE sets the variable to
the contents of each input record that is read. The final value of the
variable is the last record read from VARIABLE's primary input stream. The
variable remains unchanged if no records are read from the primary input
stream.
Note: that VARIABLE
with the TRACKING operand, when it is the first stage of a pipeline; writes
an infinite number of records unless you limit the number of records.
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The following streams are used by the VARIABLE stage:
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Stream
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Action
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Primary input stream
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VARIABLE reads records from its primary
input stream, if it is connected and writes them the specified ooRexx array.
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Primary
output stream
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VARIABLE
writes records to its primary output stream, if it is connected.
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1.
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VARIABLE does not delay the records.
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2.
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If
the VARIABLE stage discovers that both its primary input and primary output streams
are not connected, the VARIABLE stage ends.
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3.
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With
the TRACKING operand, when it is the first stage of a pipeline; writes an
infinite number of records unless you limit the number of records.
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4.
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VARIABLE verifies that it has
either/and a primary input stream and primary output stream connected and
then begins execution.
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5.
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You should be mindful of the way
in which ooRexx handles variable definitions when you use the VARIABLE stage.
In order to assign a new value to an existing variable; you must provide the
name of the variable as an explicit literal argument on the VARIABLE stage.
Consider the following example:
**** Top of file **** 1 Address Rxpipe 2 3 /* A simple stem with four elements. */ 4 5 mystem.1 = "The" 6 mystem.2 = "quick" 7 mystem.3 = "brown" 8 mystem.4 = "fox" 9 mystem.0 = 4 10 11 'pipe variable mystem.3', /* Retrieve the value in element number 3 */ 12 '| change /brown/ /red/', /* Change "brown" to "red" */ 13 '| var' mystem.3 /* Set the new value of element number 3, you think! */ 14 15 Do i = 1 to mystem.0 16 Say "mystem."i" = " || mystem.i 17 End 18 19 Say "brown = " || brown 20 21 Exit 0 **** End of file ****
output:
mystem.1 =
"The"
mystem.2 =
"quick"
mystem.3 =
"brown"
mystem.4 =
"fox"
brown = red
Note. The value in mystem.3 remains unchanged, because
the name of the variable provided by ooRexx to the VARAIBLE stage on line: 13
was interpreted as brown (the value of mystem.3), hence the variable
named brown is assigned the value
red. To ensure that
variable names are treated as literal definitions; always provide the
variable as an explicit literal argument:
10 ... 11 'pipe variable mystem.3', /* Retrieve the value in element number 3 */ 12 '| change /brown/ /red/', /* Change "brown" to "red" */ 13 '| var mystem.3' /* Set the new value of element number 3, correctly! */ 14 ... |
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1.
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/* FINDMAX EXEC */
parse arg x y
/* get arguments in x and y */
maxnum = max(x, y)
/* find largest of the two */
'pipe var maxnum | > MAX FILE A' /* write largest to MAX FILE A */
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2.
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/* READLAST EXEC */
'pipe literal a b c | split | var letter tracking'
say 'The letter you want is ' letter
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3.
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4.
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/* CHECKNAM EXEC */
'pipe',
'<' userid()
'NAMES', /* read user's CMS NAMES
file */
'| split before string
/:/', /* split
lines before colons */
'| find
:nick.'||, /* find
beginning of a nickname */
'| count lines', /* count the number of nicknames
*/
'| var namewrds' /* set variable with the count */
/* issue messages based on count */
if namewrds > 100 then say "You
know lots of people, don't you!"
else
say "You should try to get out more often!"
exit
ARRAY, STEM
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Version
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Date
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Action
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Description
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Pipelines
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1.1
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28.12.2021
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changed
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Application-wide rewrite.
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2.1
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1.0
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04.02.2012
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created
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First version.
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2.0
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