well the difference is, that [+],... are binops while [sin],... are unary operations.
the [bang(-method for binops is there for things like | [t b f] | | [+ ] |
since this is not needed it is not there for unops.
I wonder what should be outout by a bang to a unary object. Right now the result of the last operation is not stored - a respective field would have to be added to the object. That's exactly what an [f] object does in a patch.
best greetings, Thomas