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We use dependency injection to match State names to parameters of Behavior functions—the State numberOfStates gets injected into any Behavior function that list

We use dependency injection to match State names to parameters of Behavior functions—the State numberOfStates gets injected into any Behavior function that lists is as a parameter, like function(numberOfStates). We need to have a talk. First, this isn't dependency injection - you're passing in data. These "Behavior" functions may depend on the data, but that doesn't make this a dependency. Oh, I can understand how you're confused. You see Angular doing it and reverse-engineered the term. But notice how in Angular it is used to pass services into controllers, services that the controller has a dependency on. Also, notice how this "feature" is broken in production. Any website worth its salt will minify the assets, which changes function parameter names. You did notice that, right, that your clever little hack works great in your development environment but totally breaks when you minify your code? You are testing things minified, right? Why would you spend any time at all working on a feature that is fundamentally broken in production? Kill your darlings.

aikah 11y ago
> Any website worth its salt will minify the assets In Angular you'd assign a property called $inject to make "DI" still work even with minification, so it's not really an issue.Or you can explicitly pass a array with dependency names when a service is registered. So there is no issue here. Now I don't know how Famous works and i'm not interested in using that 2M dollars vaporware. I'm just saying.
- postnihilism 11y ago
  Many build tools will allow you to simply annotate functions that are meant to have their dependencies injected so you can avoid explicitly typing out the verbose array syntax. (e.g. https://github.com/olov/ng-annotate https://github.com/olov/ng-annotate)
JustSomeNobody 11y ago
Wait, are they seriously trying to say that "function(numberOfStates)" is dependency injection?
- mikeryan 11y ago
  In angular that's basically how it works. The framework actually calls toString on the functions which actually allow you to parse out the arguments names so the callers know which arguments (dependencies) need to be passed.
- JustSomeNobody 11y ago
  I have to reply because I can't edit. To the down voters: Function(numberOfStates) is a function call with data being passed in. Function(stateMachineFactory) is dependency injection.
zackbrown 11y ago
> These "Behavior" functions may depend on the data, but that doesn't make this a dependency. Would you mind clarifying this distinction as you see it? As far as I can see, x depends on y if and only if y is a dependency of x. This would make the States that Behaviors depend on a 'dependency,' based on your statement above that 'functions ... depend on the data [States].' These State dependencies (if we can agree on the term) are injected dynamically based on the names of the parameters in the Behavior functions. I'm not one to bike-shed on terminology, but I do think it's fair to say that we have dependencies that we're dynamically injecting. If it looks like a duck and quacks like a duck, it's probably a duck. Perhaps the distinction you're flagging on vs Angular is that Angular injects a reference to the dependency, whereas Famous injects the value of the dependency?
- JustSomeNobody 11y ago
  Because state is data. You operate on data, not depend on it. My repository depends on a database connection (be it mock or real). It does not depend on what state the tables may be in. If your function operates on data, it's "passing in data" and not "dependency injection". Hell, otherwise, every function call would involve dependency injection!
  - zackbrown 11y ago
    Would you accept that a Haskell function could depend on the streams that are bound into it? Not an individual datum, but the stream itself. I'd argue 'yes', in the same sense that you could depend on some model or factory in OO land. The leap is in the paradigm, functional vs OO. Behaviors in BEST are a functional programming construct—they project streams of data into a return value. Note that Behaviors are automatically re-evaluated every time one of their dependent States change, which introduces this 'stream' functionality. I'd argue that these streams are dependencies and that they're being injected into these functions (hence DI,) but honestly, at this point we're just bike-shedding about terminology :-). I do want to make sure, though, that this functionality is properly communicated, as the State-Behavior relationship is the crux of our framework's design.

aikah 11y ago

> Any website worth its salt will minify the assets In Angular you'd assign a property called $inject to make "DI" still work even with minification, so it's not really an issue.Or you can explicitly pass a array with dependency names when a service is registered. So there is no issue here. Now I don't know how Famous works and i'm not interested in using that 2M dollars vaporware. I'm just saying.

postnihilism 11y ago
Many build tools will allow you to simply annotate functions that are meant to have their dependencies injected so you can avoid explicitly typing out the verbose array syntax. (e.g. https://github.com/olov/ng-annotate https://github.com/olov/ng-annotate)

JustSomeNobody 11y ago

Wait, are they seriously trying to say that "function(numberOfStates)" is dependency injection?

mikeryan 11y ago
In angular that's basically how it works. The framework actually calls toString on the functions which actually allow you to parse out the arguments names so the callers know which arguments (dependencies) need to be passed.
JustSomeNobody 11y ago
I have to reply because I can't edit. To the down voters: Function(numberOfStates) is a function call with data being passed in. Function(stateMachineFactory) is dependency injection.

zackbrown 11y ago

> These "Behavior" functions may depend on the data, but that doesn't make this a dependency. Would you mind clarifying this distinction as you see it? As far as I can see, x depends on y if and only if y is a dependency of x. This would make the States that Behaviors depend on a 'dependency,' based on your statement above that 'functions ... depend on the data [States].' These State dependencies (if we can agree on the term) are injected dynamically based on the names of the parameters in the Behavior functions. I'm not one to bike-shed on terminology, but I do think it's fair to say that we have dependencies that we're dynamically injecting. If it looks like a duck and quacks like a duck, it's probably a duck. Perhaps the distinction you're flagging on vs Angular is that Angular injects a reference to the dependency, whereas Famous injects the value of the dependency?

JustSomeNobody 11y ago
Because state is data. You operate on data, not depend on it. My repository depends on a database connection (be it mock or real). It does not depend on what state the tables may be in. If your function operates on data, it's "passing in data" and not "dependency injection". Hell, otherwise, every function call would involve dependency injection!
- zackbrown 11y ago
  Would you accept that a Haskell function could depend on the streams that are bound into it? Not an individual datum, but the stream itself. I'd argue 'yes', in the same sense that you could depend on some model or factory in OO land. The leap is in the paradigm, functional vs OO. Behaviors in BEST are a functional programming construct—they project streams of data into a return value. Note that Behaviors are automatically re-evaluated every time one of their dependent States change, which introduces this 'stream' functionality. I'd argue that these streams are dependencies and that they're being injected into these functions (hence DI,) but honestly, at this point we're just bike-shedding about terminology :-). I do want to make sure, though, that this functionality is properly communicated, as the State-Behavior relationship is the crux of our framework's design.