SYNOPSIS
    string * P_CLASS_PATTERN  "ClassPattern"

    string * Set(P_CLASS_PATTERN, string value)
    string * Query(P_CLASS_PATTERN)
      or
    string SetClassPattern(string value)
    string QueryClassPattern()

DESCRIPTION
    The property holds the regular-expression pattern used by 
    /std/thing::class_id() to recognize textual references to the object.
    In contrast to P_ID_PATTERN, the value of this property depends only
    on the class ids and adjectives.

    The property is set by the class_id() function itself whenever its current
    value is 0. Since every change to the object's class-ids and 
    class-adjectives resets P_CLASS_PATTERN back to 0, the pattern is 
    guaranteed to be up to date.

    The actual generation is done with the sefun gen_id_pattern(). The
    property is provided for debugging purposes only. It can be set to
    any value, but should be set to 0 only if at all.

EXAMPLE
    QueryClassPattern()  -- returns the current regexp pattern.
    SetClassPattern(0)   -- resets the pattern, it will be recreated with
                            the next call to class_id().
AVAILABILITY
    Include: <properties.h>

    Availability: /std/thing(/description) and descendants.

SEE ALSO
    thing(S), classads(P), classids(P), classpattern(P)