Hi,

Maybe I missed something in specification but it is described in the standard:

20.1.3 Else branch in alternatives
"The last branch in an alt statement can be defined as an else branch by including the else keyword between the open and close brackets at the beginning of the alternative.
...
NOTE 1: It is also possible to use else in altsteps."

20.1.6 Invocation of altsteps as alternatives
"TTCN-3 allows the invocation of altsteps as alternatives in alt statements (see clause 16.2.3)."

What I think about is lack of full description of altsteps invocation in clause 20.1.6.
It is written earlier that altsteps may use 'else' branch in alternatives. I assume this should be last branch of an alt statement and last branch of an altstep. Invocation of an altstep with 'else' branch as an alternative in an alt statement will cause processing of alternatives to be finished just after an altstep, default not to be activated and the next alternative to be taken into account is the first alternative of an alt statement.

I hope it should be explicitly mentioned that an altstep with 'else' branch can not be invoked from an alternative of an alt statement with the only exception that it may be the last alternative in an alt statement.

BR,
Mariusz Kupiec