I think it would be nice if you could give an explicit type.
For example:
uint64_t(42), char(2), string(hello)

+1

Also, this is not a parser for CASH, but a new implementation of caf::from_string. You can check whether the string starts with "@<>..." and use the existing implementation in this case. Otherwise, do a full parse over the string, extracting type informations for each element on the fly.

Sorry to crash the party late...but what are "signatures" and when do they come up?

I'm sorry, i didn't explain. When using send you need to write the types of your message in front of the real message. It looks like this: send 4 @atom+@i32+i32( 'add', 5, 9). By signature i mean the part in front of the message, so @atom+@i32+@i32.
The task would be to use send in a comfortable way like send 4 'add' 5 9.

Also, this is not a parser for CASH, but a new implementation of caf::from_string. You can check 
whether the string starts with "@<>..." and use the existing implementation in this case. Otherwise, do a 
full parse over the string, extracting type informations for each element on the fly.

I'm wondering what the @<>... is, i'm pretty sure it's possible to send messages without it.

Obsoleted by libcaf_python.