(node-property propname snl #!key default: null: rcs?:)
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 “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 “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 “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.