Using BPM as the unit for tempo.
TODO: Consider a higher-fidelity way to calculate BPM, although I'm not sure
this is critical functionality; an interesting problem is just seducing me, and
this app would be better off resisting the temptation.
Elm reminds me of Haskell. In fact, I'm using `haskell-mode` (for now) in Emacs
to write my Elm code, and it works reliably. I'm not writing a Haskell app, but
if I were, I would define my application Model with the following Haskell code:
```haskell
data Model = Model { whitelistedChords :: [Theory.Chord]
, selectedChord :: Theory.Chord
, isPaused :: Bool
, tempo :: Int
}
```
When I first modelled my application state, I did something similar. After
reading more Elm examples of SPAs, I see that people prefer using type aliases
to define records. As far as I know, you cannot do this in Haskell; I believe
all types are "tagged" (something about "nominal typing" comes to mind). Anyhow,
Elm isn't Haskell; Haskell has cool features like type classes; Elm has cool
features like human-readable error messages and exhaustiveness checking for
cases. I love Haskell, and I love Elm, and you didn't ask.
Anyhow, this commit refactors my records as type aliases instead of types. I
think the resulting code is more readable and ergonomic.
Create a more convincing representation of the piano.
I would like to compute the left-offset based on the naturalWidth. That change
is probably forthcoming.
First of all, Elm's purity is beautiful. I think every language should model
their error messages and develop experience after Elm. If I didn't have to
download packages, I don't think I would need an internet connection to
troubleshoot my program's errors. This is how helpful I find the compiler.
Now that that's out of the way, here's what I've changed since we've last
corresponded:
- Use Elm's Browser.element to create a reactive application with state
- Write a function to generate all of the chords about which CDS knows
- Move some code out of Main.elm into other modules
- Depend on List.Extra, Random, Random.Extra
What's left:
- Lots of work
- Instead of clicking a button to show a new chord, use a timer
- Add mobile-first styling (probably add TailwindCSS)
- Persist settings in LocalStorage (and then eventually create user accounts)
- Allow users to curate the list of chords they're interested in practicing
- Deploy the website and dogfood it
Unknowns:
- How can I handle tempo? I don't expect setInterval to be enough (maybe it
is)...
Initialize an Elm application to build a MVP for the Chord Drill Sergeant
application. There isn't much to see at the moment. I'm just sketching
ideas. More forthcoming...
