January, 2015

Conditional injection with scala play and guice

It’s been a crazy year for me. For those who don’t know I moved from the east coast to the west coast to work for a rather large softare company in seattle (I’ll let you figure which one out) and after a few short weeks realized I made a horrible mistake and left the team. I then found a cool job at a smaller .net startup that was based in SF and met some awesome people and learned a lot. But, I’ve been poached by an old coworker and am now going to go work at a place that uses more open source things so I decided to kick into gear and investigate scala and play.

For the most part I’m doing a mental mapping of .NET’s web api framework to the scala play framework, but the more I play in play (pun intended) the more I like it.

On … Read more

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Quickly associate file types with a default program

I use JuJuEdit to open all my log files since it starts up fast, is pretty bare bones, but better than notepad. The way my log4net appender is set up is that log files are kept for 10 days and get a .N appended to them for each backup. I.e.

FooLog.log
FooLog.log.1
FooLog.log.2

Etc.

I hate having to go through each one and set the default program to open since its slow and annoying. A faster way is to use cmd (not powershell!) and use the assoc and ftype commands.

You can associate an extension (like .2) with a “file type” (which doesn’t really mean anything) and then map the file type to a program to open.

For example:

>ftype logfile="C:\Program Files (x86)\Jujusoft\JujuEdit\JujuEdit.exe" %1
>assoc .3=logfile
>assoc .4=logfile
>assoc .5=logfile
>assoc .6=logfile
...

And now they all open with juju edit. If i ever want to change it I … Read more

Creating stronger value type contracts

I’ve long been annoyed that value types don’t have strong semantic information attached to them such that the compiler would barf if I try and pass an value type that isn’t semantically the same as what the function wanted. For example, what does the following signature mean other than than taking in 2 ints and returning a bool?

IsLoggedIn :: int -> int -> bool

What I’d really like the signature to look like is

IsLoggedIn :: UserId -> SessionId -> bool

In F# you can do this sort of with type aliases and augmenting the signature with the type information. However, its just editor magic, it doesn’t actually compile to anything that would stop you from accidentally calling a function with the arguments reversed. An int is an int is an int, right?

var userId = 1
var sessionId = 2

IsLoggedIn(sessionId, userId)

This is perfectly valid to the … Read more

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