Erlang is so clear.

Ah the clearness of erlang.

Someone on the yaws list gets errors and asks:

Can any one please explain me what this error is about and how to
overcome this one?

and gets the reply

Well - it's fairly clear. It says:

{undef,[{compile,file,
["/home/phanikar/.yaws/yaws/default/m1.erl",
[binary,return_errors, ...

That means that when .yaws page has been transformed into an
.erl page, the yaws server cannot compile the generated .erl file
You need to have the erlang compiler in the load path

I'm going to assume the author was being sarcastic about that being clear, I mean I get that it couldn't compile something.. but.. no hint of what reasons it couldn't compile.

maybe to quote the awesome tude of of the dynamic window manager guys:

This keeps its userbase small and elitist. No novices asking stupid questions.

Well despite some of these problems erlang is super awesome. It just needs a little more new blood to inject new attitudes of usability [ or some other language will evbentually just steal it's good ideas, which would be a shame.. we have them now. ] Also new attitudes around easier sharing of libraries. [ the erlware guys get that. ].

I'm pretty proud to see Uncle Jesse and the gang here trying to contribute improvements all the time. Better mnesia on disk tables in the works, yaws and erlang patches, erlrc, automatic mnesia fragmentation mangment and loads more. I mean we're building a big and real distributed mnesia backed system so we're learning a lot, and we're certainly not the only ones contributing lately.

So, as a novice who asks stupid questions, I'm telling the rest of you out there not to give up if you run into a few weird error messages or attitudes from language scholars who have been so entrenched they don't see what seems weird at first. Despite those few small speed bumps, there is some really powerful awesome stuff going on here. So, don't let em be elitist barge in there and get some erlang for yourself.

P.S. Pattern matching rules!!!

I'm in ur Erlangz, upgrading ur applicationz

Hot code loading is one of the sexiest features of Erlang; after all, who wants downtime? If you're running mnesia, it's also very convenient, because as we've learned mnesia does not like to be shut down (more precisely, it makes no attempt to incrementally replicate changes across brief outages, instead doing full table (re)copying; something probably nobody cares about because they never turn it off).

Erlang's hot code loading support consists of low level language and runtime features, and a high level strategy embodied by release handler. The latter is a very Java-esque strategy of bundling up the complete new state of the system and upgrading everything. Without being normative let's just say that we enjoy using our OS package manager to manage the software on our boxes, and so we were interested in integrating Erlang hot code loading with the OS package manager.

The result is erlrc, which when operating looks something like this:

pmineiro@ub32srvvmw-199% sudo apt-get install egerl
Reading package lists... Done
Building dependency tree    
Reading state information... Done
The following packages will be upgraded:
egerl
1 upgraded, 0 newly installed, 0 to remove and 34 not upgraded.
Need to get 0B/113kB of archives.
After unpacking 0B of additional disk space will be used.
WARNING: The following packages cannot be authenticated!  egerl
Install these packages without verification [y/N]? y
(Reading database ... 48221 files and directories currently installed.)
Preparing to replace egerl 4.0.1 (using .../archives/egerl_4.1.0_all.deb) ...
Unpacking replacement egerl ...
erlrc-upgrade: Upgrading 'egerl': (cb8eec1a1b85ec017517d3e51c5aee7b) upgraded
Setting up egerl (4.1.0) ...
erlrc-start: Starting 'egerl': (cb8eec1a1b85ec017517d3e51c5aee7b) already_running

Basically, I issued an apt command, the result was to hot upgrade the corresponding Erlang application on the running Erlang node on the machine.

In addition to integration with the OS package manager, erlrc also features an extensible boot procedure (basically, using a boot directory instead of a boot file to determine what to start, which makes packaging easier); and in addition erlrc will automatically generate appup files which correspond to most of the common cases outlined in the appup cookbook. Of course, Erlang packages made with fw-template-erlang are automatically instrumented for erlrc (but the instrumentation is inert if erlrc is not installed).

If you're interested, there's more extensive documentation on google code.

Cooter to talk “Beautiful Concurrency with Erlang" at OSCON

Our buddy Cooter is going to be giving a talk at OSCON entitled

“Beautiful Concurrency with Erlang"

Congrats cooter.