option to assert validity of results

[catwell]

I have updated the Python binding to the latest version of nanomsg today. They do something different than us which is interesting: they raise exceptions when the result from nanomsg is unexpected.

We could have a mode that does the same thing, which could even be the default. It would simplify usage of the lib. For instance, the main loop of the echo server currently looks like this:

local cid, err = rep:bind( ADDRESS )
assert( cid, nn.strerror(err) )
local msg, sz
msg, err = rep:recv_zc()
assert( msg, nn.strerror(err) )
echo = msg:tostring()
print( "GOT:", '"' .. echo .. '"' )
sz, err = rep:send( echo, #echo )
assert( sz > 0, nn.strerror(err) )
rep:shutdown( cid )

Note that we don't check the result of nn_shutdown...

With that mode it would look like this:

local cid = rep:bind( ADDRESS )
local msg = rep:recv_zc()
echo = msg:tostring()
print( "GOT:", '"' .. echo .. '"' )
local sz = rep:send( echo, #echo )
rep:shutdown( cid )

Thoughts?

EDIT: I can implement it, I just want to know what you think about the idea doing it and submitting a PR.

[neomantra]

Definitely looks nicer, and I do appreciate exceptions in C++, Ruby, and Python. They aren't so common in Lua though.

Can you paste what you would wrap around the second code sample to catch the error? Wrap it in a function and pcall it?

[catwell]

Yes. I would not use that style everywhere, sometimes you need fine-grained error handling, this is why I want that as an option. But sometimes you just want things to fail if an error happens. For instance a web application calling a service over nanomsg could log the error and return a generic HTTP 500 error to users.