50.1. $valueInfo: $fieldInfoExtended, $classInfoExtended, and $createClassDscrExtended

$fieldInfo, $classInfo, and $createClassDscr use a representation of a CLASS that is not sufficiently general to describe everything that can be in a MAINSAIL CLASS. As a temporary feature, more general forms of these PROCEDUREs (named $fieldInfoExtended, $classInfoExtended, and $createClassDscrExtended, respectively) provide a more complete description of a MAINSAIL CLASS. These PROCEDUREs use records of the CLASS $valueInfo to describe the fields of a CLASS:

CLASS $valueInfo (
    STRING              $valueName;
    INTEGER             $valueType;
    LONG INTEGER        $valueDspl;
    STRING              $valueBounds;
    POINTER($classDscr) $valueClass;
    POINTER($valueInfo) $valueNext;
    );

One record is allocated for each CLASS field described. The meanings of the fields of $valueInfo for a field f of a CLASS c are as follows:

• $valueName: f's identifier.

• $valueType: The extended type code for f.

• $valueDspl: The displacement from the start of a c record at which f's value is stored (same as $LDSP(c.f)).

• $valueBounds: If f is an inplace ARRAY field, a STRING describing the inplace ARRAY's bounds as a space-separated series of space-separated lower and upper bounds; i.e., the format is lb1 ub1 for a one-dimensional ARRAY, lb1 ub1 lb2 ub2 for a two-dimensional ARRAY, or lb1 ub1 lb2 ub2 lb3 ub3 for a three-dimensional ARRAY.

  If f is not an inplace ARRAY, $valueBounds is the empty STRING (currently, no bounds information is available for a dynamic ARRAY).

• $valueClass: If f is an inplace record, the CLASS descriptor for the record's CLASS; otherwise NULLPOINTER (currently, no CLASS information is available for classified POINTERs or ADDRESSes).

• $valueNext: A link to the $valueInfo record for c's next field.

Although the PROCEDUREs that use $valueInfo are more general than the corresponding older PROCEDUREs, they are still not sufficiently general to describe a MAINSAIL CLASS completely (for example, there is no way to distinguish between a POINTER and a dynamic ARRAY). Accordingly, the $valueInfo CLASS and all the PROCEDUREs that use it are subject to change (or replacement with completely different facilities) in a future version of MAINSAIL.

50.1.1. $fieldInfoExtended

POINTER($valueInfo)
PROCEDURE   $fieldInfoExtended
                        (POINTER p;
                         STRING fieldName;
                         OPTIONAL POINTER($area) area;
                         OPTIONAL POINTER($valueInfo)
                             recToUse);

$fieldInfoExtended returns a POINTER to a $valueInfo record describing the field named fieldName of the record or CLASS descriptor pointed to by p. If recToUse is specified, it is reused (its fields are filled in and the same POINTER is returned). Newly allocated data (if any) go into area.

50.1.2. $classInfoExtended

POINTER($valueInfo)
PROCEDURE   $classInfoExtended
                        (POINTER p;
                         PRODUCES OPTIONAL STRING
                             className;
                         PRODUCES OPTIONAL
                             POINTER($classDscr) cd;
                         OPTIONAL POINTER($area) area);

$classInfoExtended returns a POINTER to a linked list of $valueInfo records describing the fields associated with p. className, cd, and area have the same meaning as the corresponding parameters to $classInfo.

50.1.3. $createClassDscrExtended

POINTER($classDscr)
PROCEDURE   $createClassDscrExtended
                        (STRING className;
                         POINTER($valueInfo) fieldList);

$createClassDscrExtended creates a CLASS descriptor at runtime for a new CLASS named className with the fields specified by fieldList.