then operator
The left-associative, binary then operator evaluates its right operand only
when it's left operand is true, otherwise it evaluates as null.
Usage
void m(String s) {
String? s2 = s.empty then "hello";
}
Description
Definition
The then operator is defined in terms of an if expression as follows
if (lhs) then rhs else null
See the language specification for more details.
The then/else idiom
The then operator is often used with the else operator to emulate
C's ternary operator cond ? when-true-expr : when-false-expr, like so
T|F result = cond then whenTrueExpr else whenFalseExpr;
Compared to if expressions
Distinct from the then/else idiom Ceylon has a separate if expression:
if (cond) then whenTrueExpr else whenFalseExpr;
The if expression is more powerful than the then/else idiom, since it
supports flow typing of is, exists or nonempty conditions to the branches
Type
The result type of the then operator is the optional type of the right hand operand;
