A Case for Common Expressions

The case function has the following signatures: expression case(Edm.Boolean:expression, ..., Edm.Boolean:expression) {{ expression case(Edm.Boolean:expression, ..., Edm.Boolean:expression,expression)}} Each Edm.Boolean:expression parameter is a tuple separated by a colon, where the first component evaluates to a Boolean value, and the second component may be an expression of any type. The case function returns the expression value of the leftmost parameter, whose first component evaluates to true. If none of the parameters match, case returns null, unless the last parameter is an expression, whose value is returned otherwise. Revised proposal 2018-4-19: The client SHOULD ensure that all parameter expressions are compatible. If all parameter expressions are of the same type, the type of the case expression is of that type. If all parameter expressions are of numeric type, then the type of the case expression is a numeric type capable of representing any of these expressions according to standard type promotion rules. Services MAY support case expressions containing parameters of incompatible types, in which case the case expression is treated as Edm.Untyped and its value has the type of the parameter expression selected by the case statement. Simplified proposal 2018-08-30 : all parameters are expression pairs with a colon, the "default" can be achieved by making the last pair true:expression .