An ActiveRecord Model of Jazz??
So we’ve been learning about ActiveRecord here at Flatiron School, and how it’s a really awesome ORM that makes things much easier for us in developing applications. I’ve also known for a while that there is a connection between music theory and programming, especially with Python, and I wondered if there were a way to combine it with Ruby.
Jazz Model is an ActiveRecord model of concepts in Jazz theory, establishing relationships between chords and scales, and much more.
The core of Jazz Toolbox is a full Ruby object model representing concepts of Jazz theory All chord/scale/mode/etc. definitions are stored as a mathematical system (sequences of numbers) which are then used to perform calculations.
For example, putting some chord in a different key is a matter of adding an arbitrary delta of half-steps and doing modulo 12.
The Jazz Model Module
Their classes often inherit from their base Jazz Module.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
We can see that the module inherits from ActiveRecord, and that it uses a sqlite3 adapter by default. However, we learned that ActiveRecord is relational database agnostic. Definitions are things like, chords, scales, etc. And here’s an example of a class – the Chord class!
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
We have associations happenin’, yo. In our study of ActiveRecord so far, we’ve learned that objects can be related to one another; namely, a chord has many tones (makes sense), a chord has many voicings (these are inversions, a version of the chord that uses the same notes but in a different arrangement and note in the bass of the chord. But we can also see that it belongs_to chord quality – namely, there’s a class called ChordQuality, and we can see a bit of it here:
1 2 3 4 5 6 7 8 9 10
The relationship is reciprocated! And here’s a quick look at what’s going on in the database – this is a very truncated view and only represents the creation of the chords table!
1 2 3 4 5 6 7 8 9 10 11 12 13 14
We can also see a nice implementation of the tap method in our table creation. Below, we can see some of the usages of the method notes(), which returns an array of the notes of a chord. For music theory buffs, notice that it returns the correctly-spelled notes, not just the enharmonically easier ones!
1 2 3 4 5 6 7 8 9 10
Who knew there would be a “notes” method for chords in Ruby? I sure didn’t. And you can solve problems like these:
1 2 3 4 5 6 7 8 9
Anyway, I think this could be a fun open-source project to contribute to.