Compaq BASIC for OpenVMS
Alpha and VAX Systems
User Manual
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22.9.1 Character String Data Types

There are two CDD/Repository character string data types, TEXT and VARYING STRING. The TEXT data type translates directly into the BASIC STRING data type. VARYING STRING is not a supported BASIC data type; therefore, BASIC creates a group to contain the field.

The following example is a CDD/Repository definition that contains both the TEXT and VARYING STRING data types and the translated BASIC RECORD statement:

Example 22-1 CDDL 

define record CDD$top.basic.strings 
    description is 
 
        /* test */. 
 
    basicstrings structure. 
        abc         datatype is text size is 10. 
        xyz         datatype is varying string size is 16. 
    end basicstrings structure. 
end strings.

Example 22-2 Translated RECORD Statement 

     1          %INCLUDE %FROM %CDD "CDD$TOP.BASIC.STRINGS" 
        C1              !   test 
        C1              RECORD  BASICSTRINGS               ! UNSPECIFIED 
        C1                STRING  ABC  = 10                ! TEXT 
        C1                GROUP   XYZ                      ! VARYING STRING 
        C1                  WORD    WORD_VALUE 
        C1                  STRING  STRING_VALUE  = 16 
        C1                END GROUP 
        C1              END RECORD 
................1 
%BASIC-I-CDD/SUBGRO, 1:        data type in CDD/Repository not supported, 
                substituted group for: BASICSTRINGS::XYZ.

In the VARYING STRING data type, the actual character string is preceded by a 16-bit count field. Therefore, BASIC creates a WORD variable to hold the specified string length.

Note
The count field preceding the VARYING STRING is actually an UNSIGNED WORD. Therefore, the count field of a VARYING STRING whose length is greater than 32,767 is interpreted by BASIC as a negative number.

In the previous example, the group name (XYZ) is the same name as a CDD/Repository field. Therefore, BASIC supplies an additional name for the RECORD components. The supplied names are WORD_VALUE and STRING_VALUE. For example, the following program statement creates an instance of the record BASICSTRINGS, called MY_REC: 


100      MAP (TEST) BASICSTRINGS MY_REC

The names you use to reference these components in BASIC are MY_REC::XYZ::WORD_VALUE and MY_REC::XYZ::STRING_VALUE.

22.9.2 Integer Data Types

CDD/Repository refers to integer data types as fixed-point data types. CDD/Repository supports BYTE, WORD, LONGWORD, QUADWORD, and OCTAWORD integer data types. Each of these data types can have the following additional attributes:

SIGNED
UNSIGNED
SIZE
DIGITS
FRACTION
BASE
SCALE

In CDDL, if integer data types are not specified as being signed or unsigned, the default is unsigned. BASIC supports only signed BYTE, signed WORD, signed LONGWORD, and signed QUADWORD integers. If a CDD/Repository data definition containing an unsigned BYTE, WORD, LONGWORD, or QUADWORD integer is extracted, BASIC signals the informational message "Datatype in CDD/Repository not supported, substituted group for: <field-name>," and creates a group to contain the field. Because the group name is the same as the CDD/Repository field name, BASIC assigns a new name to the field. This is shown in the following CDDL data definition and corresponding BASIC RECORD statement:

CDDL Definition 


define record CDD$top.basic.integers 
    description is 
 
       /*Test of selected integer data types*/. 
    basicint structure. 
        my_byte         datatype is signed byte. 
        my_ubyte        datatype is byte. 
        my_word         datatype is signed word. 
        my_uword        datatype is unsigned word. 
        my_long         datatype is signed longword. 
        my_ulong        datatype is unsigned longword. 
    end basicint structure. 
end integers.

Translated RECORD Statement 


     1          %INCLUDE %FROM %CDD "CDD$TOP.BASIC.INTEGERS" 
        C1              !  Test of selected integer data types 
        C1              RECORD  BASICINT                   ! UNSPECIFIED 
        C1                BYTE    MY_BYTE                  ! SIGNED BYTE 
        C1                GROUP   MY_UBYTE                 ! UNSIGNED BYTE 
        C1                  BYTE    BYTE_VALUE 
        C1                END GROUP 
        C1                WORD    MY_WORD                  ! SIGNED WORD 
        C1                GROUP   MY_UWORD                 ! UNSIGNED WORD 
        C1                  WORD    WORD_VALUE 
        C1                END GROUP 
        C1                LONG    MY_LONG                  ! SIGNED LONGWORD 
        C1                GROUP   MY_ULONG                 ! UNSIGNED LONGWORD 
        C1                  LONG    LONG_VALUE 
        C1                END GROUP 
        C1              END RECORD 
................1 
%BASIC-I-CDDSUBGRO, 1:        data type in CDD/Repository not supported, 
                substituted group for: BASICINT::MY_UBYTE. 
%BASIC-I-CDDSUBGRO, 1:        data type in CDD/Repository not supported, 
                substituted group for: BASICINT::MY_UWORD. 
%BASIC-I-CDDSUBGRO, 1:        data type in CDD/Repository not supported, 
                substituted group for: BASICINT::MY_ULONG.

When the previous data definition is extracted from CDD/Repository, BASIC signals an informational message for each of the unsigned data types, and names the CDD/Repository unsigned byte field BYTE_VALUE, the CDD/Repository unsigned word field WORD_VALUE, and the CDD/Repository unsigned longword field LONG_VALUE.

BASIC does not support OCTAWORD integers. If a CDD/Repository definition contains an OCTAWORD integer, BASIC signals the informational message "Datatype in CDD/Repository not supported, substituted group for: <field-name>" and creates a group to contain the field and a string component within the group. The string component is 16 bytes for OCTAWORD integers. For example:

CDDL Definition 


define record CDD$top.basic.bigintegers 
    description is 
 
        /*Test of quadword and octaword integer data types*/. 
 
    basicint structure. 
        my_quad         datatype is signed quadword. 
        my_octa         datatype is signed octaword. 
    end basicint structure. 
end bigintegers.

Translated RECORD Statement 


     1          %INCLUDE %FROM %CDD "CDD$TOP.BASIC.BIGINTEGERS" 
        C1              !  Test of quadword and octaword integer data types 
        C1              RECORD  BASICINT                   ! UNSPECIFIED 
        C1                QUAD   MY_QUAD                   ! SIGNED QUADWORD 
        C1                GROUP   MY_OCTA                  ! SIGNED OCTAWORD 
        C1                  STRING  STRING_VALUE  = 16 
        C1                END GROUP 
        C1              END RECORD 
%BASIC-I-CDDSUBGRO,           data type in CDD/Repository not supported, 
                substituted group for: BASICINT::MY_OCTA.

CDD/Repository supports the SCALE keyword to specify an implied exponent in integer data types, and the BASE keyword (supported in CDDL only) to specify that the scale for a fixed-point field is to be interpreted in a numeric base other than 10. BASIC does not support these integer attributes. Therefore, BASIC signals the informational message "CDD/Repository specifies SCALE for <name>. Not supported" for fixed-point fields containing a SCALE specification, and the error message "CDD/Repository attributes for <name> are other than base 10" for fixed-point fields specifying a base other than 10. For example:

CDDL Definition 


define record CDD$top.basic.funnyintegers 
    description is 
 
        /* Test of quadword and octaword integer data types */. 
 
    basicint structure. 
        my_byte         datatype is signed byte scale 2. 
        my_long         datatype is signed longword base 8. 
    end basicint structure. 
end funnyintegers.

Translated RECORD Statement 


     1          %INCLUDE %FROM %CDD "CDD$TOP.BASIC.FUNNYINTEGERS" 
        C1              !   Test of quadword and octaword integer data types 
        C1              RECORD  BASICINT                   ! UNSPECIFIED 
        C1                GROUP   MY_BYTE                  ! SIGNED BYTE 
        C1                  BYTE    BYTE_VALUE 
        C1                END GROUP 
        C1                LONG    MY_LONG                  ! SIGNED LONGWORD 
        C1              END RECORD 
%BASIC-I-CDDATTSCA,     CDD specifies SCALE for BASICINT::MY_BYTE. Not supported 
%BASIC-E-CDDATTBAS,     CDD attributes for BASICINT::MY_LONG are other than base 10

At compilation time, BASIC also signals these warning errors for each reference to fields that are not base 10 or that have a SCALE.

22.9.3 Floating-Point Data Types

CDD/Repository supports F_floating, D_floating, G_floating, and H_floating data types. These correspond to the BASIC SINGLE, DOUBLE, GFLOAT, and HFLOAT1 data types, respectively. As with fixed-point data types, CDD/Repository also allows the specification of scale and base for floating-point data types. If a CDD/Repository data definition contains a floating-point field that specifies a SCALE or BASE, BASIC signals the informational message "CDD/Repository specifies SCALE for <name>. Not supported" or the error message "CDD/Repository attributes for <name> are other than base 10." For example:

CDDL Definition 


define record floats 
    description is 
 
       /*Test of floating-point data types*/. 
 
    basicfloat structure. 
        my_single       datatype is f_floating scale 3. 
        my_double       datatype is d_floating base 16. 
        my_gfloat       datatype is g_floating. 
        my_hfloat       datatype is h_floating. 
    end basicfloat structure. 
end floats.

Translated RECORD Statement 


     1          %INCLUDE %FROM %CDD "CDD$TOP.BASIC.FLOATS" 
        C1              !  Test of floating-point data types 
        C1              RECORD  BASICFLOAT                 ! UNSPECIFIED 
        C1                GROUP   MY_SINGLE                ! F_FLOATING 
        C1                  SINGLE  SINGLE_VALUE 
        C1                END GROUP 
        C1                DOUBLE  MY_DOUBLE                ! D_FLOATING 
        C1                GFLOAT  MY_GFLOAT                ! G_FLOATING 
        C1                HFLOAT  MY_HFLOAT                ! H_FLOATING 
        C1              END RECORD 
................1 
%BASIC-I-CDDATTSCA, 1:   CDD specifies SCALE for BASICFLOAT::MY_SINGLE. 
                         Not supported 
%BASIC-E-CDDATTBAS, 1:   CDD attributes for BASICFLOAT::MY_DOUBLE 
                         are other than base 10

In addition, CDD/Repository supports complex floating-point numbers, but BASIC does not support them. Complex floating-point numbers consist of a real and an imaginary part. Each part requires the same amount of storage as a simple floating-point number. Therefore, each complex floating-point number requires twice as much storage as a simple floating-point number.

If a CDD/Repository data definition containing complex numbers is extracted, BASIC signals the informational message "Datatype in CDD/Repository not supported, substituted group for <field-name>", and creates a group to contain the field. As before, BASIC uses the data type and _VALUE to create the group name, but because each complex number contains both a real and an imaginary part, BASIC adds an "_R" to the name of the real part and an "_I" to the name of the imaginary part. This is shown in the following CDD/Repository data definition and corresponding BASIC RECORD statement:

CDDL Definition 


define record CDD$top.basic.complex 
    description is 
 
        /* test complex data types */. 
 
        complex structure. 
        my_s_complex_1  datatype         f_floating_complex. 
        my_d_complex_1  datatype         d_floating_complex. 
        my_g_complex_1  datatype         g_floating_complex. 
        my_h_complex_1  datatype         h_floating_complex. 
    end complex structure. 
end complex.

Translated RECORD Statement 


     1          %INCLUDE %FROM %CDD "CDD$TOP.BASIC.COMPLEX" 
        C1              !   test complex data types 
        C1              RECORD  COMPLEX               ! UNSPECIFIED 
        C1                GROUP   MY_S_COMPLEX_1      ! F_FLOATING_COMPLEX 
        C1                  SINGLE  SINGLE_R_VALUE 
        C1                  SINGLE  SINGLE_I_VALUE 
        C1                END GROUP 
        C1                GROUP   MY_D_COMPLEX_1      ! D_FLOATING_COMPLEX 
        C1                  DOUBLE  DOUBLE_R_VALUE 
        C1                  DOUBLE  DOUBLE_I_VALUE 
        C1                END GROUP 
        C1                GROUP   MY_G_COMPLEX_1      ! G_FLOATING_COMPLEX 
        C1                  GFLOAT  GFLOAT_R_VALUE 
        C1                  GFLOAT  GFLOAT_I_VALUE 
        C1                END GROUP 
        C1                GROUP   MY_H_COMPLEX_1      ! H_FLOATING_COMPLEX 
        C1                  HFLOAT  HFLOAT_R_VALUE 
        C1                  HFLOAT  HFLOAT_I_VALUE 
        C1                END GROUP 
        C1              END RECORD 
................1 
%BASIC-I-CDDSUBGRO, 1:        data type in CDD/Repository not supported, 
                substituted group for: COMPLEX::MY_S_COMPLEX_1. 
%BASIC-I-CDDSUBGRO, 1:        data type in CDD/Repository not supported, 
                substituted group for: COMPLEX::MY_D_COMPLEX_1. 
%BASIC-I-CDDSUBGRO, 1:        data type in CDD/Repository not supported, 
                substituted group for: COMPLEX::MY_G_COMPLEX_1. 
%BASIC-I-CDDSUBGRO, 1:        data type in CDD/Repository not supported, 
                substituted group for: COMPLEX::MY_H_COMPLEX_1.

22.9.4 Decimal String Data Types

CDD/Repository supports the following forms of decimal string data types:

BASIC supports only the PACKED DECIMAL decimal string data type, which corresponds to the BASIC DECIMAL data type. For all other decimal string data types, BASIC creates a group with the same name as the CDD/Repository subordinate field, and creates a string record component to contain the field. For example:

CDDL Definition 


define record CDD$top.basic.decimalstring 
    description is 
 
        /* test decimal string data types */. 
 
    decimalstring structure. 
        my_packed_decimal          datatype is packed decimal 
                                            size is 5 digits 2 fractions. 
        my_zoned_numeric           datatype is zoned numeric 
                                            size is 6 digits 2 fractions. 
        my_unsigned_numeric        datatype is unsigned numeric 
                                            size is 8 digits 4 fractions. 
        my_lef_sep_numeric         datatype is left separate numeric 
                                            size is 10 digits 3 fractions. 
        my_left_ovpnch_numeric     datatype is left overpunched numeric 
                                            size is 5 digits 2 fractions. 
        my_right_sep_numeric       datatype is right separate numeric 
                                            size is 3 digits 1 fractions. 
        my_right_ovpnch_numeric    datatype is right overpunched numeric 
                                            size is 4 digits 2 fractions. 
    end decimalstring structure. 
end decimalstring.

Translated RECORD Statement 


     1          %INCLUDE %FROM %CDD "CDD$TOP.BASIC.DECIMALSTRING" 
        C1              !  test decimal string data types 
        C1              RECORD  DECIMALSTRING              ! UNSPECIFIED 
        C1                DECIMAL(5 ,2 ) MY_PACKED_DECIMAL ! PACKED DECIMAL 
        C1                GROUP   MY_ZONED_NUMERIC         ! ZONED NUMERIC ! 
        C1                  STRING  STRING_VALUE  = 6 
        C1                END GROUP 
        C1                GROUP   MY_UNSIGNED_NUMERIC      ! UNSIGNED NUMERIC 
        C1                  STRING  STRING_VALUE  = 8 
        C1                END GROUP 
        C1                GROUP   MY_LEF_SEP_NUMERIC       ! NUMERIC LEFT 
                                                           ! SEPARATE 
        C1                  STRING  STRING_VALUE  = 11 
        C1                END GROUP 
        C1                GROUP   MY_LEFT_OVPNCH_NUMERIC   ! NUMERIC LEFT 
                                                           ! OVERPUNCHED 
        C1                  STRING  STRING_VALUE  = 5 
        C1                END GROUP 
        C1                GROUP   MY_RIGHT_SEP_NUMERIC     ! NUMERIC RIGHT 
                                                           ! SEPARATE 
        C1                  STRING  STRING_VALUE  = 4 
        C1                END GROUP 
        C1                GROUP   MY_RIGHT_OVPNCH_NUMERIC  ! NUMERIC RIGHT 
                                                           ! OVERPUNCHED 
        C1                  STRING  STRING_VALUE  = 4 
        C1                END GROUP 
        C1              END RECORD 
%BASIC-I-CDDSUBGRO,           data type in CDD/Repository not supported, 
                substituted group for: DECIMALSTRING::MY_ZONED_NUMERIC. 
%BASIC-I-CDDSUBGRO,           data type in CDD/Repository  not supported, 
                substituted group for: DECIMALSTRING::MY_UNSIGNED_NUMERIC. 
%BASIC-I-CDDSUBGRO,           data type in CDD/Repository not supported, 
                substituted group for: DECIMALSTRING::MY_LEF_SEP_NUMERIC. 
%BASIC-I-CDDSUBGRO,           data type in CDD/Repository not supported, 
                substituted group for: DECIMALSTRING::MY_LEFT_OVPNCH_NUMERIC. 
%BASIC-I-CDDSUBGRO,           data type in CDD/Repository not supported, 
                substituted group for: DECIMALSTRING::MY_RIGHT_SEP_NUMERIC. 
%BASIC-I-CDDSUBGRO,           data type in CDD/Repository not supported, 
                substituted group for: DECIMALSTRING::MY_RIGHT_OVPNCH_NUMERIC.

22.9.5 Other Data Types

CDD/Repository supports the following additional data types:
BIT
DATE
POINTER
UNSPECIFIED
VIRTUAL
ALPHABETIC

BASIC does not support these data types. BASIC translates these data types by signaling the informational message "Datatype in CDD/Repository not supported, substituted group for: <field name>", and creates a group to contain the field. See Table 22-2 for a description of how BASIC translates these data types.

If you extract a CDD/Repository definition that contains a BIT field, the field must be a multiple of 8 bits (1 byte). This means that the following field must be aligned on a byte boundary. If the following field is not aligned on a byte boundary, BASIC signals the error "Field <name> from CDD/Repository has bit offset or length."

Note

1 Compaq BASIC for OpenVMS Alpha (Alpha BASIC) does not support the HFLOAT data type.

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