Appendix: NED XML Binding¶

This appendix presents the abstract syntax tree (AST) of the NED language and message definitions, in the form of the DTD of the AST’s XML representation.
<!ELEMENT ned-file (comment*, (package|import|property-decl|property|
                    simple-module|compound-module|module-interface|
                    channel|channel-interface)*)>
<!ATTLIST ned-file
     filename           CDATA     #REQUIRED
     version            CDATA     "2">

<!-- comments and whitespace; comments include '//' marks. Note that although
     nearly all elements may contain comment elements, there are places
     (e.g. within expressions) where they are ignored by the implementation.
     Default value is a space or a newline, depending on the context.
 -->
<!ELEMENT comment EMPTY>
<!ATTLIST comment
     locid              NMTOKEN   #REQUIRED
     content            CDATA     #IMPLIED>

<!ELEMENT package (comment*)>
<!ATTLIST package
     name               CDATA     #REQUIRED>

<!ELEMENT import (comment*)>
<!ATTLIST import
     import-spec        CDATA     #REQUIRED>

<!ELEMENT property-decl (comment*, property-key*, property*)>
<!ATTLIST property-decl
     name               CDATA     #REQUIRED
     is-array           (true|false) "false">

<!ELEMENT extends (comment*)>
<!ATTLIST extends
     name               CDATA     #REQUIRED>

<!ELEMENT interface-name (comment*)>
<!ATTLIST interface-name
     name               CDATA     #REQUIRED>

<!ELEMENT simple-module (comment*, extends?, interface-name*, parameters?, gates?)>
<!ATTLIST simple-module
     name               NMTOKEN   #REQUIRED>

<!ELEMENT module-interface (comment*, extends*, parameters?, gates?)>
<!ATTLIST module-interface
     name               NMTOKEN   #REQUIRED>

<!ELEMENT compound-module (comment*, extends?, interface-name*,
                           parameters?, gates?, types?, submodules?, connections?)>
<!ATTLIST compound-module
     name               NMTOKEN   #REQUIRED>

<!ELEMENT channel-interface (comment*, extends*, parameters?)>
<!ATTLIST channel-interface
     name                NMTOKEN   #REQUIRED>

<!ELEMENT channel (comment*, extends?, interface-name*, parameters?)>
<!ATTLIST channel
     name                NMTOKEN   #REQUIRED>

<!ELEMENT parameters (comment*, (property|param)*)>
<!ATTLIST parameters
    is-implicit         (true|false)  "false">

<!ELEMENT param (comment*, property*)>
<!ATTLIST param
     type               (double|int|string|bool|object|xml) #IMPLIED
     is-volatile        (true|false)  "false"
     name               CDATA     #REQUIRED
     value              CDATA     #IMPLIED
     is-pattern         (true|false)  "false"
     is-default         (true|false)  "false">

<!ELEMENT property (comment*, property-key*)>
<!ATTLIST property
     is-implicit        (true|false) "false"
     name               CDATA     #REQUIRED
     index              CDATA     #IMPLIED>

<!ELEMENT property-key (comment*, literal*)>
<!ATTLIST property-key
     name               CDATA     #IMPLIED>

<!ELEMENT gates (comment*, gate*)>

<!ELEMENT gate (comment*, property*)>
<!ATTLIST gate
     name               NMTOKEN   #REQUIRED
     type               (input|output|inout) #IMPLIED
     is-vector          (true|false) "false"
     vector-size        CDATA     #IMPLIED>

<!ELEMENT types (comment*, (channel|channel-interface|simple-module|
                               compound-module|module-interface)*)>

<!ELEMENT submodules (comment*, submodule*)>

<!ELEMENT submodule (comment*, condition?, parameters?, gates?)>
<!ATTLIST submodule
     name               NMTOKEN   #REQUIRED
     type               CDATA     #IMPLIED
     like-type          CDATA     #IMPLIED
     like-expr          CDATA     #IMPLIED
     is-default         (true|false) "false"
     vector-size        CDATA     #IMPLIED>

<!ELEMENT connections (comment*, (connection|connection-group)*)>
<!ATTLIST connections
     allow-unconnected (true|false) "false">

<!ELEMENT connection (comment*, parameters?, (loop|condition)*)>
<!ATTLIST connection
     src-module          NMTOKEN   #IMPLIED
     src-module-index    CDATA     #IMPLIED
     src-gate            NMTOKEN   #REQUIRED
     src-gate-plusplus  (true|false) "false"
     src-gate-index      CDATA     #IMPLIED
     src-gate-subg       (i|o)     #IMPLIED
     dest-module         NMTOKEN   #IMPLIED
     dest-module-index   CDATA     #IMPLIED
     dest-gate           NMTOKEN   #REQUIRED
     dest-gate-plusplus (true|false) "false"
     dest-gate-index     CDATA     #IMPLIED
     dest-gate-subg      (i|o)     #IMPLIED
     name                NMTOKEN   #IMPLIED
     type                CDATA     #IMPLIED
     like-type           CDATA     #IMPLIED
     like-expr           CDATA     #IMPLIED
     is-default         (true|false) "false"
     is-bidirectional   (true|false) "false"
     is-forward-arrow   (true|false) "true">

<!ELEMENT connection-group (comment*, (loop|condition)*, connection*)>

<!ELEMENT loop (comment*)>
<!ATTLIST loop
     param-name          NMTOKEN   #REQUIRED
     from-value          CDATA     #IMPLIED
     to-value            CDATA     #IMPLIED>

<!ELEMENT condition (comment*)>
<!ATTLIST condition
     condition           CDATA     #IMPLIED>

<!ELEMENT literal (comment*)>
<!-- Note: value is in fact REQUIRED, but empty attr value should
     also be accepted because that represents the "" string literal;
     "spec" is for properties, to store the null value and "-",
     the antivalue.
 -->
<!ATTLIST literal
     type  (double|quantity|int|bool|string|spec)  #REQUIRED
     text                CDATA     #IMPLIED
     value               CDATA     #IMPLIED>

<!--
  **  'unknown' is used internally to represent elements not in this NED DTD
  -->
<!ELEMENT unknown        ANY>
<!ATTLIST unknown
     element             CDATA     #REQUIRED>