Default Arguments for Code Types
Sometimes it is the case, particularly for actions, that some arguments take default values. In making such declarations we can use the keyword
default followed by a value of the required type. In such cases all the arguments with default values must appear at the end and, in use, if an argument is given a value other than its default then all previous arguments with defaults have to be also given a value (usually its default value). Below are examples from the builtin (system) declarations.
act write_list(TermList : !list(@term),
Stream : !stream_type default stdout)
"Write TermList to Stream."
act connect_to_pedro(Host : !atom default localhost,
Port : !int default 4550)
"Connect to the pedro server on Host using Port."
In the second example if the Pedro server on this machine was started using, say port 5000, then we would need to use
connect_to_pedro(localhost, 5000)
