Erlang CSV Parser

At long last I've finished the CSV parser I've been working on.  Most of the technical problems have been string matching problems, and that a string is a list of integers that can be matched singly prefixing a dollar sign to the char that should be matched.

The parser uses a state machine implemented by using a process and messages the next char until it reaches the end of the file/string at which point it messages an eof atom and awaits the process to message back the parsed CSV.  In the end the parser used quite a lot of erlang's features including processes, funs and parametrised macros and the end result was pretty clean.  It can take a plain string or an IO device such as a file as the string source which is handled in a nice way using funs to get the next char.  I found the switch from OOP to functional confusing at first since I wanted to use an input stream but the functional method I discovered is probably smaller than the Java stream based approach I would have used otherwise.

Other notable CSV parsers include ppolv's and an FSM OTP behaviour from Praveen Ray of Yellowfish.  I'm really impressed by the OTP behaviour, I can imagine this would improve reuse once comfortable with erlang and the OTP.

Learing Erlang

I've been learning Erlang on and off for a while and I still can't believe how high the bar to entry is to create something relatively simple.  By this I mean that I mean the large amount of new skills and tools that I need to be familiar with before I even get coding.  I'm not talking about the language itself here as I understand that a learning my first functional language isn't going to be an easy switch as it would be for C# to Java or vice versa.

I've run into two hurdles before tonight which has slowed me down and one just now which has compelled me to write about it.  Number one is a bug in eunit (a bug in a unit testing framework!!!), this really had me stumped for a while.  I believed I was working from a copy that I checked out from the eunit SVN repository and dutifully went through the code:add_path motions to update the repo to get the bug fix.  However eunit is actually part of the core libraries so I had to apply the given patch to the erlang distribution, in the end downloading the newest Erlang fixed the problem. 

All through development I've had a problem automating the compilation of my code, going down a dead end path with erlangantlib then make not being able to interpret the eunit make file when I was tinkering with it as above.  This was all crappy and gave me a bad feeling but this is all part of getting to know the language that doesn't have IBM, Sun or Microsoft backing it.  Mores the pity.

The final bullet was the debugger not being able to start and giving an erl.exe has encountered a problem message.  I know why because the excuse is in the Erlang Programming book, the tools in Erlang to my knowledge are all built using the TCL UI toolkit which is really crap on Windows.  Cheers, this feels like a real waste of my time.  Am I really supposed to start using Linux just to work proficiently in Erlang?

I'm not going to give up on Erlang just yet, its features are still far too compelling to let go of.