DFDL expressions
DFDL expressions can be used to set some properties dynamically at processing-time.
For example, a message might contain a 'count' element whose value gives the number of occurrences of a later element that is an array. The array element uses an expression in the Occurs Count property, which refers to the 'count' element.
The DFDL expression language is a subset of XPath 2.0. Expressions follow XPath 2.0 syntax rules, but are always enclosed in braces '{' and '}'.
The properties that support DFDL expressions include:
- assert (the test property of the assert takes the expression)
- binary float rep
- byte order
- discriminator (the test property of the discriminator takes the expression)
- encoding
- escape character
- escape escape character
- initiator
- input value calc
- length
- occurs count
- output new line
- output value calc
- separator
- terminator
- text boolean false rep
- text boolean true rep
- text standard decimal separator
- text standard exponent character
- text standard grouping separator