DataBasic Elements

Statement Labels

Reality accepts the following:

• A label can have one or more spaces between the label identifier and the terminating colon.
• A label's terminating colon can be followed by a semicolon (see Multi-statement Line). This allows a comment to be included on the same line as the label.
• A label can have the same name as a literal, symbol or variable.

Predefined Symbols

In MVENTERPRISE mode (set with the $OPTIONS statement), the following additional predefined symbols are available:

Symbol	Value	Description
@DAY	DATE() 'DD'	Current day of the week.
@MONTH	DATE() 'DM'	Current month.
@YEAR	DATE() 'DY'	Current year.

Substring Extraction

Reality will accept an alternative syntax for substring extraction, whereby if the length parameter is omitted, a positive start# parameter is treated as shorthand for a negative start# parameter, combined with a length parameter with the same value. For example, the expression VAR[3] produces the same result as VAR[-3,3]; that is, it extracts the last three characters of VAR.

This is used on many other MultiValue systems.

Pattern Matching

In MVENTERPRISE mode (set with the $OPTIONS statement), multiple patterns used with the MATCH(ES) operator can be separated by any of the Reality system delimiters – attribute mark (@AM), value mark (@VM) or subvalue mark (@SM or @SVM).

Strings as Logical Expressions

In Reality mode, if a non-numeric string is used as a logical (Boolean) expression, a run-time error is generated and the result is false (see Logical Expressions). In MVENTERPRISE mode (set with the $OPTIONS statement), a non-numeric string evaluates to true and no error is generated.

Format Strings

• In Reality mode, format strings operate as described.
• In MVENTERPRISE mode (set with the $OPTIONS statement), if a scaling factor is specified, the current precision (set with the PRECISION statement) is subtracted from this before being applied and the M modifier has no effect. If the result is negative, a scaling factor of 0 is used.
• In other MultiValue modes, if a scaling factor is specified, the current precision is subtracted from this before being applied. The M modifier has no effect.

Example

PRECISION 4

A = 1234.56789

PRINT A "3"
PRINT A "32"
PRINT A "35"

If this program is run in Reality mode and other MultiValue modes, the results are as follows:

Reality mode	MVENTERPRISE mode	Other MultiValue mode
1234.568 12.346 0.012	1234.568 1234.568 123.457	1234.568 123456.789 123.457

• In the first PRINT statement, no scaling factor is specified and the result is the same in all three modes.

• In the second PRINT statement, a scaling factor of 2 is specified and the result therefore depends on the mode.

  • In Reality mode, the value of A is simply descaled by a factor of 2.
  • In MVENTERPRISE mode, the scaling factor is subtracted from the current precision (4) before being applied. This gives a negative scaling factor, so 0 is used.
  • In other MultiValue modes, the scaling factor is subtracted from the current precision (4) before being applied, giving an effective scaling factor of minus 2.

• In the third PRINT statement, a scaling factor of 5 is specified and therefore the result also depends on the mode.

  • In Reality mode, the value of A is simply descaled by a factor of 5.
  • In other MultiValue modes, the scaling factor is subtracted from the current precision (4) before being applied. This gives an effective scaling factor of 1.

Item Locks

DataBasic and Proc allow you to take multiple locks on the same item (this will normally occur if the item is processed by a number of different programs or subroutines, each of which locks the item). On Reality, each of these locks must be separately released, while some other MultiValue systems (for example, Power 95) require only a single release operation.

If required, a Reality database can be configured to work in a similar way to these MultiValue systems by setting the database configuration parameter MvStyleItemLocks to 1.

User Exits

In all MultiValue modes (selected with the $OPTIONS statement), if a user exit is called with the ICONV or OCONV function, a runtime error occurs and 0 is returned.