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	<?xml version="1.0" encoding="UTF-8"?>
	<chapter version="5.1" xmlns="http://docbook.org/ns/docbook"
	xmlns:xlink="http://www.w3.org/1999/xlink"
	xmlns:xila="http://www.w3.org/2001/XInclude/local-attributes"
	xmlns:xi="http://www.w3.org/2001/XInclude"
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	xmlns:svg="http://www.w3.org/2000/svg"
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	xmlns:html="http://www.w3.org/1999/xhtml"
	xmlns:db="http://docbook.org/ns/docbook">
	<?xxe-sn 2b06cb2u4g0 1?>

	<title><?xxe-sn 2b06cb2u4g0 2?>Xreate Manual</title>

	<para><?xxe-sn 2b06cb2u4g0 6?>Xreate is an open source general purpose high
	level programming language designed to write efficient and safe computer
	programs.</para>

	<para><?xxe-sn 2b06cb2u4g0 8?>Here "high level" has very specific meaning,
	implying an ability to easily write, read, as well as adapt software to a
	constantly changing environment or business goals. In this respect, any
	software product can be evaluated on the basis of the three dimensions:
	efficiency, safety, and adaptability. Unfortunately, those properties are
	proved to be largely contradictory, for it is manageable to write either
	efficient (yet unsafe) or safe (yet impractical) code, but not both. Thus,
	the ultimate goal of the language is to allow developers to produce code
	that would have all these properties at the same time. Xreate's design
	principles allow to adopt any programming technique as long as it does not
	improve one dimension at the expense of another.</para>

	<para><?xxe-sn 2b06cb2u4g0 7?>To achieve the aforementioned design goals,
	Xreate employs three distinctive layers:</para>

	<itemizedlist>
	<?xxe-sn 2b06cb2u4g0 e?>

	<listitem>
	<?xxe-sn 2b06cb2u4g0 f?>

	<para><?xxe-sn 2b06cb2u4g0 g?><link xlink:href="/w/syntax"><?xxe-sn 2b06cb2u4g0 o?>Brute</link>.
	The lowest layer is called <emphasis><?xxe-sn 2b06cb2u4g0 p?>Brute
	</emphasis>— this is code that is intended to be actually compiled. Code
	on this level implements actual software functionality. It resembles the
	usual imperative languages' apparatus and consists of executable
	instructions such as arithmetic, branching, input/output, etc.</para>
	</listitem>

	<listitem>
	<?xxe-sn 2b06cb2u4g0 i?>

	<para><?xxe-sn 2b06cb2u4g0 j?><link xlink:href="/w/transcend"><?xxe-sn 2b06cb2u4g0 q?>Transcend</link>.
	Brute level alone is not enough to constitute a full-fledged language
	since code requires various non-executable metadata to express
	developer's intents, check correctness, validity and perform other types
	of analyses. In Xreate everything of this sort belongs to a layer called
	<emphasis><?xxe-sn 2b06cb2u4g0 s?>Transcend</emphasis>. Transcend due to
	its declarative nature is appropriate to do management-type work — it
	analyzes, oversees and controls brute by guiding compilation process.
	Everything on this level — logic or transcend facts and rules — is
	gathered and sent to an external logic solver to make solutions that are
	brought back in order to guide compilation.</para>
	</listitem>

	<listitem>
	<?xxe-sn 2b06cb2u4g0 l?>

	<para><?xxe-sn 2b06cb2u4g0 m?><link
	xlink:href="/w/concepts/interpretation/"><?xxe-sn 2b06cb2u4g0 r?>Interpretation</link>.
	There is also <emphasis><?xxe-sn 2b06cb2u4g0 t?>Interpretation</emphasis>
	— the intermediate level resembling dynamically typed languages that is
	used as a contact point and interpreter between brute and transcend and
	their respective low level and high level constructs and
	structures.</para>
	</listitem>
	</itemizedlist>

	<para><?xxe-sn 2b06cb2u4g0 u?>On a syntactic level, Xreate is a procedural
	language with extensive use of <emphasis><?xxe-sn 2b06cb2u4g0 v?><link
	xlink:href="/w/transcend"><?xxe-sn 2b06cb2u4g0 w?>annotations</link></emphasis>
	— arbitrary unconstrained metadata that software developer can attach to
	different language constructs, variables and code blocks. Annotations are
	completely invisible for the compiler proper and used by transcend more as a
	suggestion conveying additional information.</para>

	<remark><?xxe-sn 2ccp2iy80zj 1td6aqezxvj7l?>"a different language
	constructs": если подразумевается "конструкции разных языков", тогда лучше
	"different languages' constructs". Если конструкции языка, в целом, то тогда
	артикль a не нужен</remark>

	<para xlink:href="w/virtualization/"><?xxe-sn 2b3f3osfk74 g?>Most severe and
	hard to resolve problems in software development stem from interaction of
	different components on different levels. Each individual component often is
	thoroughly tested and works reliably. But combining them when building
	end-user software for which purpose complex interaction and extensive IO is
	enabled usually leads to a range of runtime errors, security vulnerabilities
	and performance degradation.</para>

	<para xlink:href="w/virtualization/"><?xxe-sn 2cdtco54w00 2?>Thus Xreate
	places key emphasis on domain-specific component level improvements and
	joint use of external resources. This aspect is covered in <link
	xlink:href="/w/exploitation/"><?xxe-sn 2b3f3osfk74 h?>exploitation</link>
	and <link xlink:href="/w/concepts/containers/"><?xxe-sn 2b3f3osfk74 i?>containers</link>
	chapters.</para>

	<para xlink:href="w/virtualization/"><?xxe-sn 2cdtco54w00 3?>Unlike academic
	languages, Xreate targets safe and reliable usage of effectful computations
	such as IO covered in <link xlink:href="/w/virtualization"><?xxe-sn 2b3f3osfk74 j?>virtualization</link>
	and <link xlink:href="/w/exploitation/"><?xxe-sn 2b3f3osfk74 k?>exploitation</link>
	chapters, and mutable structures covered in <link
	xlink:href="/w/communication/"><?xxe-sn 2b3f3osfk74 l?>communication</link>.</para>

	<section>
	<?xxe-sn 2b06cb2u4g0 3?>

	<title><?xxe-sn 2b06cb2u4g0 4?>Basic Example</title>

	<para><?xxe-sn 2b06cb2u4g0 5?>To demonstrate what Xreate is all about,
	basic example is given below:</para>

	<programlisting xml:id="Example_1"><?xxe-sn 2b06cb2u4g0 x?>name="tests/introduction.cpp: Introduction.Doc_Example_1", lines=15
	guard:: iAmVeryFast
	{
	div = function(a:: float, b:: float):: float
	{
	a / b
	}
	}

	guard:: iAmVerySafe
	{
	div = function(a:: float, b:: float):: float
	{
	if ( b == (0::float)):: float {0::float} else {a / b}
	}
	}

	test = function:: float; entry; iAmVerySecure
	{
	div(10, 5)
	}</programlisting>

	<para><?xxe-sn 2b06cb2u4g0 y?>Here entry point of the program is a
	function <code><?xxe-sn 2b06cb2u4g0 z?>test</code> recognized so by
	compiler because of annotation <code><?xxe-sn 2b06cb2u4g0 10?>entry</code>
	in its signature. There are also two functions <code><?xxe-sn 2b06cb2u4g0 11?>div</code>
	called <emphasis><?xxe-sn 2b06cb2u4g0 12?>specializations</emphasis>. Each
	specialization has a guard that defines a condition that has to be met in
	order to invoke this particular specialization. In the example,
	specializations of <code><?xxe-sn 2b06cb2u4g0 13?>div</code> have
	<code><?xxe-sn 2b06cb2u4g0 14?>iAmVeryFast</code> and <code><?xxe-sn 2b06cb2u4g0 15?>iAmVerySafe</code>
	guards, respectively. Let's say that developer specifies two
	specializations where the first one is a very fast division
	implementation, while the second one is a very safe division
	implementation since it checks division by zero, although it is
	unacceptably slow due to an extra check instruction. This is a basis of
	<link xlink:href="/w/concepts/polymorphism/"><?xxe-sn 2b3f3osfk74 2?>polymorphism</link>
	— client's code <code><?xxe-sn 2b3f3osfk74 3?>test</code> is able to work
	with any specialization, and compiler must decide which one to invoke with
	the only hint it has — annotation <code><?xxe-sn 2b3f3osfk74 5?>iAmVerySecure</code>
	in the function <code><?xxe-sn 2b3f3osfk74 7?>test</code>'s
	signature.</para>

	<remark><?xxe-sn 2ccp2iy80zj 1td6aqezxvj7n?>"provides two specializations"
	- возможно, лучший вариант "designates/assigns/allocates two
	specializations". Или даже просто specifies/indicates. (PS заменил на
	specifies)</remark>

	<remark><?xxe-sn 2ccp2iy80zj 1td6aqezxvj7m?>"unbearably slow" - я бы
	заменил на более нейтральное "too slow". Unbearable - это скорее об
	ощущениях человека. Или, если под "unbearably" имеется в виду "недопустимо
	медленный", тогда - unacceptably slow.</remark>

	<note>
	<?xxe-sn 2b3f3osfk74 n?>

	<para><?xxe-sn 2b3f3osfk74 o?>All annotations (except <code><?xxe-sn 2b3f3osfk74 m?>entry</code>)
	are custom defined by developer itself.</para>
	</note>

	<para><?xxe-sn 2b3f3osfk74 6?>This is when transcend comes into play. By
	adding a transcend rule as shown below it is possible to associate
	annotation <code><?xxe-sn 2b3f3osfk74 8?>iAmVerySecure</code> with
	invocation of specialization guarded by <code><?xxe-sn 2b3f3osfk74 9?>iAmVerySafe:</code></para>

	<programlisting xml:id="Transcend_Example_1"><?xxe-sn 2b3f3osfk74 a?>name="tests/introduction.cpp: Introduction.Doc_Example_1", lines=15
	dfa_callguard(SiteInv, iAmVerySafe):-
	dfa_callfn(SiteInv, div);
	SiteInv = s(_, _, ScopeInv);
	cfa_parent(ScopeInv, function(FnInv));
	bind_func(FnInv, iAmVerySecure).</programlisting>

	<para><?xxe-sn 2b3f3osfk74 b?>Transcend rules are written in ASP syntax —
	common syntax to write logic programs. This particular rule reads that for
	any function annotated with <code><?xxe-sn 2b3f3osfk74 c?>iAmVerySecure</code>,
	certain specialization <code><?xxe-sn 2b3f3osfk74 d?>iAmVerySafe</code> is
	chosen for <code><?xxe-sn 2b3f3osfk74 e?>div</code> invocation.</para>

	<note>
	<?xxe-sn 2b3f3osfk74 p?>

	<para><?xxe-sn 2b3f3osfk74 q?>In this example an appropriate
	specialization is statically resolved, so the other specialization isn't
	even compiled.</para>

	<remark><?xxe-sn 2ccp2iy80zj 1td6aqezxvj7o?>the, потому что их всего
	две.</remark>
	</note>

	<para><?xxe-sn 2b3f3osfk74 f?>By providing custom rules it is possible to
	implement any polymorphism strategy, be it performed statically or
	dynamically. The example demonstrates basic workflow: transcend gathers
	available information about a program such as annotations and using custom
	rules makes a decision to guide compilation process, particularly by
	selecting appropriate specializations as in the above example.</para>
	</section>

	<section>
	<?xxe-sn 2ba2e84701s 1?>

	<title><?xxe-sn 2ba2e84701s 2?>Build and Run on Linux</title>

	<para><?xxe-sn 2ba2e84701s 3?>Major dependencies:</para>

	<itemizedlist>
	<?xxe-sn 2ba2e84701s 4?>

	<listitem>
	<?xxe-sn 2ba2e84701s 5?>

	<para><?xxe-sn 2ba2e84701s 6?>gcc 7</para>
	</listitem>

	<listitem>
	<?xxe-sn 2ba2e84701s 7?>

	<para><?xxe-sn 2ba2e84701s 8?>llvm 5, clang 5</para>
	</listitem>

	<listitem>
	<?xxe-sn 2ba2e84701s 9?>

	<para><?xxe-sn 2ba2e84701s a?>boost 1.66</para>
	</listitem>

	<listitem>
	<?xxe-sn 2ba2e84701s b?>

	<para><?xxe-sn 2ba2e84701s c?>coco</para>
	</listitem>

	<listitem>
	<?xxe-sn 2ba2e84701s d?>

	<para><?xxe-sn 2ba2e84701s e?>clingo</para>
	</listitem>
	</itemizedlist>

	<para><?xxe-sn 2ba2e84701s f?>Building tested on <emphasis
	role="bold"><?xxe-sn 2ba2e84701s o?>OpenSuse Leap 15</emphasis>. Please
	change commands accordingly if using other distributions.</para>

	<para><?xxe-sn 2ba2e84701s p?>Pull sources directly from
	repository:</para>

	<literallayout><?xxe-sn 2ba2e84701s g?>git clone --recursive https://pgess@bitbucket.org/pgess/xreate.git</literallayout>

	<para><?xxe-sn 2ba2e84701s q?>Enter into the source directory and run the
	following script to prepare building environment. Script will install the
	required system packages as well as Coco and Clingo from sources:</para>

	<remark><?xxe-sn 2ccp2iy80zj 1td6aqezxvj7p?>"Enter into source directory"
	- тут перед directory явно нужен артикль. Гугл говорит, что определенный -
	the</remark>

	<important>
	<?xxe-sn 2cdtco54w00 4?>

	<para><?xxe-sn 2cdtco54w00 5?>Carefully inspect scripts before
	run</para>
	</important>

	<para><?xxe-sn 2ba2e84701s 13?>On <emphasis role="bold"><?xxe-sn 2ba2e84701s 14?>OpenSuse
	Leap 15</emphasis>:</para>

	<literallayout><?xxe-sn 2ba2e84701s t?>./installation/prepare-opensuse-leap15</literallayout>

	<para><?xxe-sn 2ba2e84701s u?>That was one time operation to prepare
	environment. After that enter into <code><?xxe-sn 2ba2e84701s v?>build</code>
	directory and start actual tests building:</para>

	<remark><?xxe-sn 2ccp2iy80zj 1td6aqezxvj7q?>"build directory": здесь ты
	все-таки вначале указываешь имя объекта (build), и лишь потом родовое
	название (directory)</remark>

	<literallayout><?xxe-sn 2ba2e84701s w?>cd build
	make</literallayout>

	<para><?xxe-sn 2ba2e84701s x?>After successful build you can run xreate
	tests:</para>

	<literallayout><?xxe-sn 2ba2e84701s y?>cd ..
	./build/tests/xreate-tests</literallayout>

	<note>
	<?xxe-sn 2ba2e84701s 1h?>

	<para><?xxe-sn 2ba2e84701s 1i?>Please pay attention that the working
	directory should be the repository root</para>
	</note>

	<para><?xxe-sn 2ba2e84701s 17?>For consequent rebuilds after updates etc
	invoke <code><?xxe-sn 2ba2e84701s 18?>cmake</code> as follows:</para>

	<literallayout><?xxe-sn 2ba2e84701s 19?>#working dir build
	cmake -DCMAKE_BUILD_TYPE=Debug \
	-DBUILD_XREATE_TESTS=1 \
	-DCOCO_EXECUTABLE=<FILE> \
	-DCLINGO_PATH=<DIR> \
	-DCOCO_FRAMES_PATH=../vendors/coco/generator/ \
	-DCMAKE_CXX_COMPILER=g++ ../cpp
	make</literallayout>

	<para><?xxe-sn 2ba2e84701s 1j?>Cmake's selected parameters:</para>

	<itemizedlist>
	<?xxe-sn 2ba2e84701s 1a?>

	<listitem>
	<?xxe-sn 2ba2e84701s 1b?>

	<para><?xxe-sn 2ba2e84701s 1c?>BUILD_XREATE_TESTS Determines whether
	to build tests</para>
	</listitem>

	<listitem>
	<?xxe-sn 2ba2e84701s 1d?>

	<para><?xxe-sn 2ba2e84701s 1e?>COCO_EXECUTABLE Full filename of Coco
	executable</para>
	</listitem>

	<listitem>
	<?xxe-sn 2ba2e84701s 1f?>

	<para><?xxe-sn 2ba2e84701s 1g?>CLINGO_PATH Installed Clingo
	directory</para>

	<remark><?xxe-sn 2ccp2iy80zj 1td6aqezxvj7r?>"Directory of Clingo
	installation": может, with Clingo installation? (это если речь идет о
	папке, где хранятся инсталляционные файлы) Если наоборот, куда будет
	устанавливаться - тогда Directory for installing Clingo. Оригинальный
	вариант ("of Clingo installation") немного сбивает с толку.</remark>
	</listitem>
	</itemizedlist>
	</section>
	</chapter>

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