Jive Expressions & Functions

Expressions

Expressions are used to set variables and in if and while control commands. They are also used to output data for HTML. A standalone expression is converted as needed to string and sent to the HTML output page.

Expressions consist of value references and operators. Value references are variable names or literals. Basic SQL operators are used. Two special operators are supported - at sign (@) and pound sign (#). A small set of functions are available.

The precedence of operators is:

#
( )
+ - (unary)
* /
+ - (binary)
= < > <> <= >=
not
and
or
@ function

Operations on nulls are the same as SQL. Three valued logic is used.

The special operators (@, #) are used with arrays and are described under var Command.

Functions

Functions are used in expressions. They take one or more expressions as arguments and return a single value. Function arguments are normally enclosed in parentheses. Multiple arguments are separated by commas.

Jive functions are:

format Function, formats a value using a picture.
isunk Function - tests an expression for null or unknown.
ifunk Function - allows a substitute value for a null expression.

Preset Variables

At startup, Jive defines a set of variables at the root level. They are normal vairable. Their values may be changed or their definitions overridden. Jive preset variables:

  Name        Type         Description
  cr          string       control character - new line
  true        bool         boolean true
  false       bool         boolean false
  calender    date         calender date at startup
  clock       time         clock time at startup
  now         timestamp    timestamp at startup

Intrinsic Values

Intrinsic values are used to determine results from SQL, input and env commands. Two values are provided - error and empty.

The error value is set following a SQL, input or env command. It indicates if an error has occurred in processing the command. error is true following an input or env command if a type other than string was defined and there was a conversion failure, otherwise it is false. error is true following a SQL command if the SQL command caused an ODBC error, otherwise it is false.

empty is set following a SQL command. It indicates that the SQL command processed no rows. SOme ODBC drivers cannot detect empty conditions on update, delete and/or insert. In this case, empty is null.

error and empty are available for a query (select) following the {end} terminating the select.