Remove 'include' in favor of XInclude

The custom MEF 'include' specification has grown redundant in view of the widespread availability of XInclude. XInclude is flexible and powerful to allow unconstrained splitting of the model as an analyst wishes.
open-psa · Oct 4, 2017 · f76bec9 · f76bec9
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diff --git a/mef/model_organization.rst b/mef/model_organization.rst
@@ -60,44 +60,23 @@ For even medium size PSA models this assumption not compatible with Quality Cont
 Moreover, such a monolithic organization of data would be very hard to manage
 when several persons work together on the same model.
 
-A first way to split the model into several files is to use the XML notion of entities:
-in any XML file, it is possible to declare file entities in the preamble,
-and to include them in the body of the document.
-This mechanism is exemplified below.
-
-.. code-block:: xml
-
-    <?xml version="1.0" ?>
-
-    <!DOCTYPE SMRF [
-    <!ENTITY file1 SYSTEM "file1.xml">
-    <!ENTITY file2 SYSTEM "file2.xml">
-    ]>
-    <smrf>
-        ...
-        &file1;
-        ...
-        &file2;
-        ...
-    </smrf>
-
-This mechanism, however, has the drawback
-that XML tools have to actually include the files into the document,
-hence, making its manipulation heavier.
-
-The Model Exchange Format proposes another simple mechanism to achieve the same goal:
-the tag include.
+The Model Exchange Format utilizes XInclude_,
+general purpose XML Include (W3C Candidate Recommendation),
+which allows splitting the model in flexible and unconstrained ways.
 This tag can be inserted at any place in a document.
-Its effect is to load the content of the given file into the model.
+Its effect is to include the content of the given file into the model.
 
 .. code-block:: xml
 
-    <opsa-mef>
+    <opsa-mef xmlns:xi="http://www.w3.org/2001/XInclude">
         ...
-        <include file="basic-events.xml"/>
+        <xi:include href="basic-events.xml"/>
         ...
     </opsa-mef>
 
+.. _XInclude: https://www.w3.org/TR/xinclude/
+
+
 Organization of a Model
 =======================
 

diff --git a/mef/schema/fault_tree.rnc b/mef/schema/fault_tree.rnc
@@ -7,8 +7,7 @@ fault-tree-definition =
      | CCF-group-definition
      | event-definition
      | component-definition
-     | parameter-definition
-     | include-directive)*
+     | parameter-definition)*
   }
 
 component-definition =
@@ -21,8 +20,7 @@ component-definition =
      | CCF-group-definition
      | event-definition
      | component-definition
-     | parameter-definition
-     | include-directive)*
+     | parameter-definition)*
   }
 
 role = attribute role { "private" | "public" }
@@ -31,8 +29,7 @@ model-data =
   element model-data {
     (house-event-definition
      | basic-event-definition
-     | parameter-definition
-     | include-directive)*
+     | parameter-definition)*
   }
 
 event-definition =

diff --git a/mef/schema/mef.rnc b/mef/schema/mef.rnc
@@ -7,11 +7,6 @@ reference =
     xsd:NCName { pattern = "([^\-.]+(-[^\-.]+)*)(\.\i[^\-.]*(-[^\-.]+)*)*" }
   }
 
-include-directive =
-  element include {
-    attribute file { xsd:string }
-  }
-
 include "model.rnc"
 include "label_and_attributes.rnc"
 

diff --git a/mef/schema/model.rnc b/mef/schema/model.rnc
@@ -13,6 +13,5 @@ model =
      | initiating-event-definition
      | fault-tree-definition
      | substitution-definition
-     | CCF-group-definition
-     | include-directive)*
+     | CCF-group-definition)*
   }