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[netrexx-pipelines] REGEX stage now with "context" and complete(?)
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From: Jeff H. <Je...@Je...> - 2020-07-01 03:19:29
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<p>I have added the CONTEXT <i>number</i> option. This reports not
only the matching record, but some before and after it also. Also
added are BEFORE and AFTER to get contextual records in one
direction. There is an optional SEPARATOR to set off the groups
of records. It defaults to "--".</p>
<p>
<blockquote type="cite"><tt>/** regex<br>
<br>
>>--<b>REGEX</b>--+--------------------------+--<i>regex_string</i>-(1)---><<br>
+-(--| <i>options_string</i> |--)-+<br>
<br>
<b>options_string</b>:<br>
+----------------------------+<br>
|--v-+------------------------+-+--|<br>
+-NUMBERS----------------+ (2)<br>
+-BEFORE-+-<i>0</i>------+------+ (3)<br>
| +-<i>number</i>-+ |<br>
+-AFTER-+-<i>0</i>------+-------+ (3)<br>
| +-<i>number</i>-+ |<br>
+-CONTEXT-+-<i>0</i>------+-----+ (4)<br>
| +-<i>number</i>-+ |<br>
+-NOSEPARATOR------------+<br>
+-SEPARATOR-+- -- ----+--+<br>
| +-<i>DString</i>-+ |<br>
<br>
Records matching the RegEx are put out on primary output<br>
Records not matching are put out on secondary, if connected,
or discarded.<br>
<br>
(1) string is a Java RegEx expresion. null string passes all
records.<br>
(2) lines are prefaced with line number, 10 characters, right
justified<br>
(3) number of records put out after a matching record<br>
(4) number of records put out before and after a matching
record<br>
<br>
*/<br>
</tt></blockquote>
<br>
This brings it up, functionally, almost to GNU GREP 3.4 (minus all
of its file input options).</p>
<p>A few things for discussion:</p>
<ul>
<li>Would it ever help to put matched records out on the tertiary
stream without the context records? Unmatched ones are already
on the secondary.</li>
<li>GREP has an option to just put out the COUNT of matched
records. Do we have any use for this? ( REGEX string | COUNT
LINES does the same.)<br>
</li>
<li>Possibly the regex_string should be a delimited string. This
because a potential REGEX_CHANGE stage would have two delimited
strings.</li>
<li>Should this be named GREP? Which term would be more or less
familiar to our users? Both? with one an alias of the other?</li>
</ul>
(Oops, just spotted a bug: BEFORE, etc, without a number works if it
is the last option, but not otherwise. Something for the morning
fix.)<br>
<p>Jeff<br>
</p>
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