raffazizzi/CORS

## CORS
<div type="div3" xml:id="CORS2"><head>Creating New Reference Systems</head>
<p>If a text has no canonical reference system of its own, a new custom reference
system may be used.</p>

<p>The global attributes <att>n</att> and <att>xml:id</att> may be used to
  assign reference identifiers to segments of the text.  Identifiers
  specified by either attribute apply to the entire element for which they
  are given.  ID attributes must be unique within a single
  document, and ID values must begin with a letter.  No such restrictions
  are made on the values of <att>n</att> attributes.
</p>

<p>Determining a referencing system for a TEI encoding depends on many factors
  that may either be derived by textual structure, or influenced by extra-textual
  contingencies such as project and file management matters. It is important,
  therefore, that the attribute used, the elements which can bear standard
  reference identifiers, and the method for constructing standard reference
  identifiers, should all be declared in the header as described in section
  <ptr target="#HD54"/>.
</p>

<p>The Guidelines do not recommend one specific method for creating new referencing
   systems; however, the rest of this section lists some possibly useful strategies.</p>

<div type="div4" xml:id="CORS2-1">
  <head>Referencing system derived from markup</head>
  <p>
    A new referencing system may be derived from the structure of the electronic
    text, specifically from the markup of the text. As with any
    reference system intended for long-term use, it is important to see the
    reference as an established, unchanging point in the text. Should the
    text be revised or rearranged, the reference-system identifiers
    associated with any bit of text must stay with that bit of text, even if
    it means the reference numbers fall out of sequence.  (A new reference
    system may always be created beside the old one if out-of-sequence
    numbers must be avoided.)
  </p>
  <p>A convenient method of mechanically generating unique values for
    <att>xml:id</att> or <att>n</att> attributes based on the structure of
    the document is to construct, for each element, a <term>domain-style
      address</term> comprising a series of components separated by full
    stops, with one component for each level of the document hierarchy.
    Two methods may be used.  In the <term>typed path</term> form of
    identifier, each component in the identifier takes the form of an
    element identifier, a hyphen, and a number, for example
    <code>p-2</code>. The element name specifies what type of
    element is to be sought, and the number specifies which occurrence of that
    element type is to be selected.  (The hyphen and number may be omitted
    if there is only one element of the given type.)  In the <term>untyped
      path</term> form of identifier, each component consists of a number,
    indicating which element in the sequence of nodes at each level is to be
    selected.  To make the resulting identifier a valid XML identifier, it
    may need to be prefixed with an unchanging alphabetic letter.</p>
    <p>Identifiers generated with these methods should use the <gi>text</gi>
      element as their starting point, rather than the <gi>TEI</gi> or
      <gi>body</gi> elements. The <gi>TEI</gi> element may be taken
      as a starting point only if identifiers need to be generated for the
      <gi>teiHeader</gi>, which is not usually the case;  using the
      <gi>body</gi> element as a root would prevent assignment of identifiers
      for the front and back matter.  The component corresponding to the root
      element can be omitted from identifiers, if no confusion will result.
      In collections and corpora, the component corresponding to the root may
      be replaced by the unique identifier assigned to the text or sample.
    </p>
  <p>In the following example, each element within the <gi>text</gi>
    element has been given a typed-path identifier as its <att>xml:id</att>
    value, and an untyped-path identifier as its <att>n</att> value; the
    latter are prefixed with the string <mentioned>AB</mentioned>, which may be
    imagined to be the general identifier for this text.
    <egXML xmlns="http://www.tei-c.org/ns/Examples"><text xml:id="Text-1" n="AB">
      <front xml:id="Front" n="AB.1">
        <div xml:id="Front.div-1" n="AB.1.1">
          <p> ... </p>
        </div>
        <titlePage xml:id="Front.titlePage" n="AB.1.2">
          <titlePart> ... </titlePart>
        </titlePage>
        <div xml:id="Front.div-2" n="AB.1.3">
          <p> ... </p>
        </div>
      </front>
      <body xml:id="Body" n="AB.2">
        <p xml:id="Body.p-1" n="AB.2.1"> ... </p>
        <p xml:id="Body.p-2" n="AB.2.2"> ... </p>
        <div xml:id="Body.div-1" n="AB.2.3">
          <head xml:id="Body.div-1.head" n="AB.2.3.1"> ... </head>
          <p xml:id="Body.div-1.p-1" n="AB.2.3.2"> ... </p>
          <p xml:id="Body.div-1.p-2" n="AB.2.3.3"> ... </p>
        </div>
        <div xml:id="Body.div-2" n="AB.2.4">
          <head xml:id="Body.div-2.head" n="AB.2.4.1"> ... </head>
          <p xml:id="Body.div-2.p-1" n="AB.2.4.2"> ... </p>
          <p xml:id="Body.div-2.p-2" n="AB.2.4.3"> ... </p>
        </div>
      </body>
    </text></egXML>
    The typed and untyped path methods are convenient, but are in no way
    required for anyone creating a reference system.
  </p>
  <p>If the <att>xml:id</att> attribute is used to record the reference
    identifiers generated, each value should record the entire path.  If the
    <att>n</att> attribute is used, each value may record either the entire
    path or only the subpath from the parent element.  The attribute
    used, the elements which can bear standard reference identifiers, and
    the method for constructing standard reference identifiers, should all
    be declared in the header as described in section <ptr target="#HD54"/>.
  </p>
</div>

</div>
	<div type="div3" xml:id="CORS2"><head>Creating New Reference Systems</head>
	<p>If a text has no canonical reference system of its own, a new custom reference
	system may be used.</p>

	<p>The global attributes <att>n</att> and <att>xml:id</att> may be used to
	assign reference identifiers to segments of the text. Identifiers
	specified by either attribute apply to the entire element for which they
	are given. ID attributes must be unique within a single
	document, and ID values must begin with a letter. No such restrictions
	are made on the values of <att>n</att> attributes.
	</p>

	<p>Determining a referencing system for a TEI encoding depends on many factors
	that may either be derived by textual structure, or influenced by extra-textual
	contingencies such as project and file management matters. It is important,
	therefore, that the attribute used, the elements which can bear standard
	reference identifiers, and the method for constructing standard reference
	identifiers, should all be declared in the header as described in section
	<ptr target="#HD54"/>.
	</p>

	<p>The Guidelines do not recommend one specific method for creating new referencing
	systems; however, the rest of this section lists some possibly useful strategies.</p>

	<div type="div4" xml:id="CORS2-1">
	<head>Referencing system derived from markup</head>
	<p>
	A new referencing system may be derived from the structure of the electronic
	text, specifically from the markup of the text. As with any
	reference system intended for long-term use, it is important to see the
	reference as an established, unchanging point in the text. Should the
	text be revised or rearranged, the reference-system identifiers
	associated with any bit of text must stay with that bit of text, even if
	it means the reference numbers fall out of sequence. (A new reference
	system may always be created beside the old one if out-of-sequence
	numbers must be avoided.)
	</p>
	<p>A convenient method of mechanically generating unique values for
	<att>xml:id</att> or <att>n</att> attributes based on the structure of
	the document is to construct, for each element, a <term>domain-style
	address</term> comprising a series of components separated by full
	stops, with one component for each level of the document hierarchy.
	Two methods may be used. In the <term>typed path</term> form of
	identifier, each component in the identifier takes the form of an
	element identifier, a hyphen, and a number, for example
	<code>p-2</code>. The element name specifies what type of
	element is to be sought, and the number specifies which occurrence of that
	element type is to be selected. (The hyphen and number may be omitted
	if there is only one element of the given type.) In the <term>untyped
	path</term> form of identifier, each component consists of a number,
	indicating which element in the sequence of nodes at each level is to be
	selected. To make the resulting identifier a valid XML identifier, it
	may need to be prefixed with an unchanging alphabetic letter.</p>
	<p>Identifiers generated with these methods should use the <gi>text</gi>
	element as their starting point, rather than the <gi>TEI</gi> or
	<gi>body</gi> elements. The <gi>TEI</gi> element may be taken
	as a starting point only if identifiers need to be generated for the
	<gi>teiHeader</gi>, which is not usually the case; using the
	<gi>body</gi> element as a root would prevent assignment of identifiers
	for the front and back matter. The component corresponding to the root
	element can be omitted from identifiers, if no confusion will result.
	In collections and corpora, the component corresponding to the root may
	be replaced by the unique identifier assigned to the text or sample.
	</p>
	<p>In the following example, each element within the <gi>text</gi>
	element has been given a typed-path identifier as its <att>xml:id</att>
	value, and an untyped-path identifier as its <att>n</att> value; the
	latter are prefixed with the string <mentioned>AB</mentioned>, which may be
	imagined to be the general identifier for this text.
	<egXML xmlns="http://www.tei-c.org/ns/Examples"><text xml:id="Text-1" n="AB">
	<front xml:id="Front" n="AB.1">
	<div xml:id="Front.div-1" n="AB.1.1">
	<p> ... </p>
	</div>
	<titlePage xml:id="Front.titlePage" n="AB.1.2">
	<titlePart> ... </titlePart>
	</titlePage>
	<div xml:id="Front.div-2" n="AB.1.3">
	<p> ... </p>
	</div>
	</front>
	<body xml:id="Body" n="AB.2">
	<p xml:id="Body.p-1" n="AB.2.1"> ... </p>
	<p xml:id="Body.p-2" n="AB.2.2"> ... </p>
	<div xml:id="Body.div-1" n="AB.2.3">
	<head xml:id="Body.div-1.head" n="AB.2.3.1"> ... </head>
	<p xml:id="Body.div-1.p-1" n="AB.2.3.2"> ... </p>
	<p xml:id="Body.div-1.p-2" n="AB.2.3.3"> ... </p>
	</div>
	<div xml:id="Body.div-2" n="AB.2.4">
	<head xml:id="Body.div-2.head" n="AB.2.4.1"> ... </head>
	<p xml:id="Body.div-2.p-1" n="AB.2.4.2"> ... </p>
	<p xml:id="Body.div-2.p-2" n="AB.2.4.3"> ... </p>
	</div>
	</body>
	</text></egXML>
	The typed and untyped path methods are convenient, but are in no way
	required for anyone creating a reference system.
	</p>
	<p>If the <att>xml:id</att> attribute is used to record the reference
	identifiers generated, each value should record the entire path. If the
	<att>n</att> attribute is used, each value may record either the entire
	path or only the subpath from the parent element. The attribute
	used, the elements which can bear standard reference identifiers, and
	the method for constructing standard reference identifiers, should all
	be declared in the header as described in section <ptr target="#HD54"/>.
	</p>
	</div>

	</div>