<stránka

	xmlns="https://trac.frantovo.cz/xml-web-generator/wiki/xmlns/strana"

	xmlns:m="https://trac.frantovo.cz/xml-web-generator/wiki/xmlns/makro">

	<nadpis>Release v0.13</nadpis>

	<perex>sixth public release of Relational pipes</perex>

	<m:release>v0.13</m:release>

	<text xmlns="http://www.w3.org/1999/xhtml">

		<p>

			We are pleased to introduce you the new development version of <m:name/>.

			This release brings the XMLTable input filter, the SQL transformation and a small improvement in the filesystem input filter: 

		</p>

		<ul>

			<li>

				<strong>XMLTable input</strong>:

				This tool does similar job like the <a href="https://www.postgresql.org/docs/current/functions-xml.html">xmltable</a> function known from SQL.

				It uses the <a href="https://www.w3.org/TR/xpath/all/">XPath</a> language for selecting parts of the input XML – one XPath expression points to record nodes

				and one or more XPath expressions point to attribute nodes/values relatively to particular record node.

				Thus it is able to produce one or more relations from an arbitrary XML input.

				The input is parsed at once and converted to DOM in memory i.e. no streaming – thus processing of huge XML files requires appropriate amounts of RAM, on the other hand: 

				our expression can access whole XML document and pick values not only from currently processed record node.

				This tool uses the <a href="http://xmlsoft.org/">Libxml2</a> library (XML parser and XPath processor).

			</li>

			<li>

				<strong>SQL transformation</strong>:

				SQL is one of most powerful languages for processing relational data and the most widespread one.

				Now it can be used even on-the-fly in shell pipelines – without having any database server running.

				It is useful for record filtering, JOINing several relations together, doing aggregations or computations.

				By default everything is done in memory, but with the <code>--file</code> parameter we can use a temporary file

				and with <code>--keep-file</code> we can make it not so temporary (n.b. in the next version this option was renamed to <code>--file-keep</code>).

				This tool uses the <a href="https://www.sqlite.org/">SQLite</a> library.

			</li>

			<li>

				<strong>file system input</strong>:

				new optional attribute has been added: <code>--file content</code>

				which allows getting the text content (currently only in the UTF-8 encoding) of the file which allows us using the file system as a simple database.

			</li>

		</ul>

		<p>

			n.b. the <code>--file</code> and <code>--file-keep</code> have been dropped in <m:a href="release-v0.16">v0.16</m:a>

			(replacement is described in the v0.16 release notes).

		</p>

		<p>

			See the <m:a href="examples">examples</m:a> and <m:a href="screenshots">screenshots</m:a> pages for details.

		</p>

		<p>

			Please note that this is still a development release and thus the API (libraries, CLI arguments, formats) might and will change.

		</p>

		<h3>Data types</h3>

		<ul>

			<li m:since="v0.8">boolean</li>

			<li m:since="v0.8">variable unsigned integer (prototype)</li>

			<li m:since="v0.8">string in UTF-8</li>

		</ul>

		<h3>Inputs</h3>

		<ul>

			<li m:since="v0.11">Recfile</li>

			<li m:since="v0.9">XML</li>

			<li m:since="v0.13">XMLTable</li>

			<li m:since="v0.9">CSV</li>

			<li m:since="v0.9">file system</li>

			<li m:since="v0.8">CLI</li>

			<li m:since="v0.8">fstab</li>

		</ul>

		<h3>Transformations</h3>

		<ul>

			<li m:since="v0.13">sql: filtering and transformations using the SQL language</li>

			<li m:since="v0.12">awk: filtering and transformations using the classic AWK tool and language</li>

			<li m:since="v0.10">guile: filtering and transformations defined in the Scheme language using GNU Guile</li>

			<li m:since="v0.8">grep: regular expression filter, removes unwanted records from the relation</li>

			<li m:since="v0.8">cut: regular expression attribute cutter (removes or duplicates attributes and can also DROP whole relation)</li>

			<li m:since="v0.8">sed: regular expression replacer</li>

			<li m:since="v0.8">validator: just a pass-through filter that crashes on invalid data</li>

			<li m:since="v0.8">python: highly experimental</li>

		</ul>

		<h3>Outputs</h3>

		<ul>

			<li m:since="v0.11">ASN.1 BER</li>

			<li m:since="v0.11">Recfile</li>

			<li m:since="v0.9">CSV</li>

			<li m:since="v0.8">tabular</li>

			<li m:since="v0.8">XML</li>

			<li m:since="v0.8">nullbyte</li>

			<li m:since="v0.8">GUI in Qt</li>

			<li m:since="v0.8">ODS (LibreOffice)</li>

		</ul>

		<p>

			Instalation was tested on Debian GNU/Linux 9.6.

			The process should be similar on other distributions.

		</p>

		<m:pre src="examples/release-v0.13.sh" jazyk="bash" odkaz="ano"/>

		<p>

			<m:name/> are modular thus you can download and install only parts you need (the libraries are needed always).

			Tools <code>out-gui.qt</code> and <code>tr-python</code> require additional libraries and are not built by default.

		</p>

		<p>

			The module <code>relpipe-in-filesystem</code> uses C++ filesystem API which is supported since GCC 8.

			This module can be compiled and seems usable even with GCC 6, but requires some patching (switch to the experimental API):

		</p>

		<m:pre jazyk="bash"><![CDATA[sed 's@#include <filesystem>@#include <experimental/filesystem>@g' -i "$RELPIPE_SRC"/relpipe-in-filesystem.cpp/src/FileAttributeFinder.h "$RELPIPE_SRC"/relpipe-in-filesystem.cpp/src/XattrAttributeFinder.h "$RELPIPE_SRC"/relpipe-in-filesystem.cpp/src/FilesystemCommand.h "$RELPIPE_SRC"/relpipe-in-filesystem.cpp/src/AttributeFinder.h

sed 's@std::filesystem@std::experimental::filesystem@g' -i "$RELPIPE_SRC"/relpipe-in-filesystem.cpp/src/FileAttributeFinder.h "$RELPIPE_SRC"/relpipe-in-filesystem.cpp/src/XattrAttributeFinder.h "$RELPIPE_SRC"/relpipe-in-filesystem.cpp/src/FilesystemCommand.h "$RELPIPE_SRC"/relpipe-in-filesystem.cpp/src/AttributeFinder.h

sed 's/.*PROPERTY CXX_STANDARD.*/#\0/g' -i "$RELPIPE_SRC"/relpipe-in-filesystem.cpp/src/CMakeLists.txt]]></m:pre>

		<p>

			The module <code>relpipe-tr-guile</code> uses GNU Guile 2.2 but can also work with 2.0.

			In such case, it requires this patch:

		</p>

		<m:pre jazyk="bash"><![CDATA[sed 's/guile-2\.2/guile-2.0/g' -i "$RELPIPE_SRC"/relpipe-tr-guile.cpp/src/CMakeLists.txt]]></m:pre>

	</text>

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