A comma `,' may be used to separate elements in an expression. OX_tag is a constant which denotes an OX message tag. SM_tag is a constant which denotes an SM command tag. If a sender AAA or a receiver BBB has to be specified, 'From AAA' or 'To BBB' is written before the OXexpression.
For example the following expression means a request to push a CMO string ``Hello''.
The following expression means a request to execute a local function ``hoge''.
In our standard encoding method, each tag is expressed as a 32 bit (4 bytes) integer with the network byte order.