Returns the value that the node represented by snl exhibits for
the property propname. If the node does not exhibit the property
propname, then if the default: is supplied, it is
returned; otherwise, an error is signaled. If the node exhibits a
null value for the property, then if null: is supplied,
it is returned; otherwise, if default: is supplied,
it is returned; otherwise, an error is signaled.
propname shall be a symbol or a string specifying either the
application name (transformed as specified in section 10.1.5, Application Name Transformation)
or the RCS name of the property. propname is compared against the
property name in a case-independent manner. Property values are represented as expression language objects
according to their abstract data type:
| • An abstract character is represented by an object of type char. |
| • An abstract string is represented by an object of type string. |
| • An abstract boolean is represented by an object of type boolean. |
| • An abstract integer is represented by an object of type integer. |
| • An abstract integer list is represented by a list of integers. |
| • An abstract string list is represented by a list of strings. |
| • An enumeration is represented by a symbol whose name is equal to
the application name of the enumerator (transformed as specified
in section 10.1.5, Application Name Transformation). |
| • A component name is represented by a symbol. The name of the symbol
shall be the application name (transformed as specified
in section 10.1.5, Application Name Transformation), unless the
rcs?: argument is supplied with a true value, in which case the
RCS name will be used. |
| • An abstract component name list is represented by a list of the symbols
that represent each component name. |
| • An abstract node is represented by a singleton node-list. |
| • An abstract nodelist is represented by an object of type node-list. |
| • An abstract nmndlist is represented by an object of type named-node-list. |
| • Null values have no representation in the expression language. |