FEEL (Friendly Enough Expression Language) is a part of the DMN specification of the OMG. It is designed to write expressions for decision tables and literal expressions in a simple way what can easily understand by business professionals and developers.
FEEL has two entry points: unary-tests and expressions.
Unary-tests can be used only for input entries of a decision table. They are a special kind of expression with a different grammar. The expression gets the value of the input expression implicitly as the first argument. The result of the expression must be either
Expressions can be used everywhere, e.g. in a decision table as input expression or output entry. An expression takes no implicit arguments like unary-tests.