REDEFINE

REDEFINE

operand1 (

nX )
operand2

This document covers the following topics:

For an explanation of the symbols used in the syntax diagram, see Syntax Symbols.

Belongs to Function Group: Reporting Mode Statements

REDEFINE Usage

The REDEFINE statement is used to redefine a field. The resulting definition may consist of one or more user-defined variables.

With one REDEFINE statement, several fields may be redefined.

REDEFINE Restriction

The REDEFINE statement is only valid in reporting mode. To redefine a field in structured mode, use the REDEFINE clause of the DEFINE DATA statement.

REDEFINE Syntax Description

Operand Definition Table:

Operand Possible Structure Possible Formats Referencing Permitted Dynamic Definition
operand1   S A G   A U N P I F B D T L C     yes no
operand2   S A G   A   N P I F B D T L C     yes yes

Syntax Element Description:

Syntax Element Description
REDEFINE operand1 operand2
Method of Redefinition:

The byte positions of operand1 are redefined from left to right regardless of format.

The format of operand2 can be different from the format of operand1. However, the data at the byte positions of operand2 should match the format specification of operand2 to avoid strange results in the output report. For example, if an alphanumeric field is redefined as numeric and does not contain numeric data according to the format specification, an abnormal termination may result when it is used. For a recommended approach to checking numeric values in an alphanumeric field, see Example 5: Checking Numeric Values in an Alphanumeric Field.

Further Redefinition:

Fields defined using a REDEFINE statement may be subsequently redefined with another REDEFINE statement.

nX
Filler Notation:

The nX notation is used to denote filler bytes within the field/variable being redefined. Any trailing nX notation is optional.

REDEFINE Examples

Example 1

The user-defined variable #A (format/length A10) contains the value 123ABCDEFG. 

REDEFINE #A (#A1(N3) #A2(A7))

The value in #A1 is 123. The value in #A2 is ABCDEFG.

Example 2

The user-defined variable #B (format/length A10) contains the value (shown in hexadecimal format) 12345CC1C2C3C4C5C6C7. 

REDEFINE #B (#B1(P4) #B2(A7))

The value in #B1 is 12345C (in hexadecimal format).

The value in #B2 is C1C2C3C4C5C6C7 (in hexadecimal format). 

REDEFINE #B (#BB1(B2)8X)) or REDEFINE #B(#BB1(B2))

The value in #BB1 is 1234 (in hexadecimal format).

Note
For packed data (Format P), the number of decimal positions required must be specified. The following formula can be used to determine the number of bytes that the packed number occupies:

Number of bytes = (number of decimal positions + 1) / 2, rounded upwards to full bytes.

Example 3 

COMPUTE #V (N8.2) = #Y (N10) = ...
REDEFINE #V (3X  #A(N3)  2X  #P (N2))  #Y (#B(N3)  7X)

Example

Example 4

This example redefines the value of the system variable *DATN, which is in the form YYYYMMDD, and displays the result as three separate fields in the order day/month/year: 

MOVE *DATN TO #DATINT (N8)
REDEFINE #DATINT (#YEAR (N4) #MONTH (N2) #DAY (N2))
DISPLAY NOTITLE #DATINT #DAY #MONTH #YEAR
END

Output:

 #DATINT  #DAY #MONTH #YEAR
--------- ---- ------ -----
                           
 20140326  26    3     2014

Example 5: Checking Numeric Values in an Alphanumeric Field

When an alphanumeric field containing characters and numeric values is redefined as numeric, accessing a value that is not valid for the numeric format may cause an abnormal termination. If you need to check for a numeric value in an alphanumeric field, it is recommended that you use the IS option. The numeric value can then be obtained using the VAL function.

For example:

DEFINE DATA LOCAL
1 #A (A4)
1 REDEFINE #A
 2 #N(N4)
END-DEFINE
#A := '-123'
IF #A IS (N4) THEN /* check if #A can be converted to numeric format
 #N := VAL(#A)     /* get the numeric value
 WRITE "TRUE"
ELSE
 WRITE "FALSE"     / * #A contains non-numeric characters and cannot be converted.
END-IF
END

In the above example, #A contains the character value '-123'. Although #A is defined as an alphanumeric field, the IS (N4) condition checks whether its content can be interpreted as a numeric value. Since '-123' is a valid numeric value, the condition is true, and VAL(#A) can be used to obtain its numeric value in #N. 

IF #N = -123
...
END-IF

The above example demonstrates that an access to a numeric defined field which contains non-numeric characters can cause an abnormal behavior. Therefore, the IS and VAL functions are recommended when accessing a redefined numeric field.

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