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CONSOLE stage v1.3
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Pipelines v2.1
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(1)
>>──┬─CONSole──┬──┬────────────┬─────────────────────────────────────────────────────><
├─SCReen───┤ └─EOF─string─┘
└─TERMinal─┘
(2)
>>────CONSole─────────────────────┬─────────────────────────────┬────────────────────><
└─DELIMit─startstr─┬────────┬─┘
└─endstr─┘
Notes:
(1) May only be specified when console is the first stage of a pipeline.
(2) May only be specified when console is not the first stage of a pipeline.
Use the CONSOLE stage to read lines from
the keyboard or write lines to the console.
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(1)
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When CONSOLE is the first stage of the
first pipeline; CONSOLE reads records from the keyboard and writes them to
its primary output stream.
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CONSOLE stops reading when:
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Its primary output stream becomes
disconnected.
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No operands are specified, CONSOLE
stops reading when a null line is entered from the keyboard. To enter a
null line, press <enter> without typing anything on the command-line.
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When the input text matches the string
specified by the EOF operand.
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Only a single active CONSOLE stage (from the moment it is initialised until
it completes processing and ends) can read from the keyboard at any one
time. You may specify multiple CONSOLE stages that read from the keyboard,
including those in a CALLPIPE chain, but only a single active instance can
have exclusive access to the keyboard for input. If more than one CONSOLE
stage attempts to secure exclusive access to the keyboard for input, at the
same time, then an error is raised and the pipeline ends.
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(2)
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When CONSOLE is not the first stage of a
pipeline; CONSOLE reads records from its primary input stream and writes them
to the console and to its primary output stream, if it is connected. CONSOLE
appends a Line-Feed character to each output record that it writes to the
console, primary output stream records are written unchanged.
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EOF
specifies that CONSOLE is to stop reading from
the keyboard when the input text matches string.
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string
is a string
that you want CONSOLE to recognise as a signal to stop reading from the
keyboard. The string is not
written to the output stream. Uppercase and lowercase representations of
the same characters do not match. CONSOLE stops reading from the keyboard
if the line read exactly matches the target string you specify.
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DELIMit
specifies that records written
to the console are prefixed and appended with a pair of delimiting character
strings. The CONSOLE stage only uses the delimiting strings when writing the
record to the console, they are not included in the record written to the
primary output stream.
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startstr
endstr
are
a pair of delimited literal strings that enclose the
record displayed on the screen.
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For example: to
display a record surrounded by a pair of quotation marks:
. . . console delimit /"/ /"/ . . .
The following streams are used by the CONSOLE stage:
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Stream
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Action
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Primary input stream
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When CONSOLE is not the first
stage of the pipeline, CONSOLE reads records from its primary input stream.
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Primary output stream
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When CONSOLE is the first stage of the first pipeline, CONSOLE
writes the records it reads from the keyboard to its primary output stream.
When CONSOLE is not the first stage of the pipeline, CONSOLE writes the
records it reads from its primary input stream to its primary output
stream.
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1.
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CONSOLE
does not delay the records.
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2.
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When
CONSOLE is the first stage of the first pipeline and it discovers that its
primary output stream is not connected, the CONSOLE stage ends.
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3.
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CONSOLE
may stop reading from the keyboard before the condition specified in the
operands is satisfied. If a stage that reads records which flow out of the
CONSOLE stage, ends or disconnects its input stream, the CONSOLE stage ends;
as in the following example: The first CONSOLE stage stops reading from the
keyboard after the second line of data or a null has been entered. (The TAKE
stage reads exactly 2 records and then disconnects is primary input stream;
causing the primary output stream of the CONSOLE stage to become
disconnected; which terminates the stage).
****
Top of file ****
1 Address Rxpipe
2
3 'pipe console',
4 '| take
2',
5 '|
console
6
7 Exit 0
****
End of file ****
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4.
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When the pipe TRACE ON option is specified
(or the pipeline has inherited the TRACE ON setting through the CALLPIPE
stage command); the CONSOLE stage encloses it's console output in angle
brackets – prefixed with the CONSOLE stage name. For example:
CONSOLE: >some output text<
However; the
CONSOLE stage only uses this output format when writing a record to the
console; records that are written to the primary output stream are written
without modification.
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5.
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CONSOLE verifies that its secondary
input and output streams are not connected and then begins execution.
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See: Usage
IN, OUT
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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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1.3
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??.??.2025
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changed
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Application-wide
rewrite.
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2.1
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1.2
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23.05.2011
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added
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When the
pipe TRACE ON option is specified (or the pipeline has inherited the TRACE ON
setting through the CALLPIPE stage command); the CONSOLE stage encloses it's
console output in angle brackets – prefixed with the CONSOLE stage name
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1.9
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1.1
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22.04.2008
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changed
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Carriage-Return
control characters are now discarded by the string operand.
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1.5
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1.0
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06.09.2007
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created
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First version.
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1.0
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