Skip to main content

Sherlock Holmes and the "Case of the Errant Erlang Macro"


The compiler dutifully informed me that:

case error_logger:logfile({open, ?IMP_LOGFILE} ) of

was giving out:

/imp_scan.erl:137: syntax error before: '}'

...and boy did I end up scratching my head until finally, applying Rule #1 (you spelled it wrong) coupled with the Holmes conjecture I realised that (a) I was indeed wrong again and (b) the compiler was correct and here was the problem:

-define(IMP_LOGFILE,"/tmp/impscan.log"}).

Yes, having decided that the string was best made a constant I refactored the code and accidentally left the trailing closing brace in the macro, hence my confusion! The error message was referring to that brace but because the parameter was itself a tuple I had become confused. Just another day on the job.

PS: As I like to call it, the "Holmes conjecture",
How often have I said to you that when you have eliminated the impossible, whatever remains, however improbable, must be the truth?
.

Comments

Post a Comment

Popular posts from this blog

Angular.JS ... absolutely awesome BUT...

Aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaagh! Sort the documentation soon please!  More soon, I really do like it though. :)
Post a Comment
Read more

PHP and Lisp: multiple-value-bind (MVB)

This is another article in my attempts to find new ways of looking at PHP and making it less of a chore to type in all that code. As much as I love PHP I hate wasting keystrokes. More typing is more errors is more grief. Being an off and on user of Lisp, although not as much as I used to, one of the things that I always liked in Lisp was the ability to be able to return multiple values from a function at once using (values) and then marry that with (multiple-value-bind) to create convenient named bindings for whatever you were about to do. I recently found myself wanting to return a couple of values from a helper function and I just didn't want to go to the trouble of having to type all those character required to create an array with keys for the two values and then I remembered MVB and a little light went on in my head! If somebody else has already done this then I apologise up front but it was new to me and I haven't seen it anywhere else so this could be a first! ...
Post a Comment
Read more

Handling multipart/form-data with NanoHTTPD

I am in the process of reviving an old project from 2014 that I never finished because of other work commitments. In that time, bitrot has set in, the Android API has moved on and all in all, the home-brewed HTTP server I wrote using SocketServer and the org.apache libraries had to go! I looked around, found a couple of contenders and after much time decided to go with NanoHTTPD because it is lean, small and fits in exactly two files. The main server is in one file `NanoHTTPD.java`and there is another file called `ServerRunner.java` which manages instances of running servers. The others The other project I looked at is this one:  https://github.com/koush/AndroidAsync which led me a merry dance and I just couldn't figure out how get the POST data I had uploaded. I spent a few days really digging at it with Wire Shark too to make sure the data was going up. It was. Whatever... I had used it via a gradle dependency entry but I dropped it and went back to NanoHTTPD. For m...
Post a Comment
Read more