Summary:
Depends on D20814. Currently, "min()" and "max()" are still "min(f, n)". This is no longer consistent with the construction of functions a function-generators that are composed at top level.
Turn them into "min(n)" and "max(n)" (i.e., not higher-order functions).
Then, mark all the functions which are pure mathematical functions and not higher-order as "pure". These functions have no function parameters and do not reference external data. For now, this distinction has no immediate implications, but it will simplify the next change (which tracks where data came from when it originated from an external source -- these pure functions never have any source information, since they only apply pure mathematical transformations to data).
Test Plan: Loaded a burnup chart, nothing seemed obviously broken.
Subscribers: yelirekim
Differential Revision: https://secure.phabricator.com/D20815
Summary:
Depends on D20446. Currently, chart functions are both configured through arguments and evaluated through arguments. This sort of conflates things and makes some logic more difficult than it should be.
Instead:
- Function arguments are used to configure function behavior. For example, `scale(2)` configures a function which does `f(x) => 2 * x`.
- Evaluation is now separate, after configuration.
We can get rid of "sourceFunction" (which was basically marking one argument as "this is the thing that gets piped in" in a weird magical way) and "canEvaluate()" and "impulse".
Sequences of functions are achieved with `compose(u, v, w)`, which configures a function `f(x) => w(v(u(x)))` (note order is left-to right, like piping `x | u | v | w` to produce `y`).
The new flow is:
- Every chartable function is `compose(...)` at top level, and composes one or more functions. `compose(x)` is longhand for `id(x)`. This just gives us a root/anchor node.
- Figure out a domain, through various means.
- Ask the function for a list of good input X values in that domain. This lets function chains which include a "fact" with distinct datapoints tell us that we should evaluate those datapoints.
- Pipe those X values through the function.
- We get Y values out.
- Draw those points.
Also:
- Adds `accumluate()`.
- Adds `sum()`, which is now easy to implement.
- Adds `compose()`.
- All functions can now always evaluate everywhere, they just return `null` if they are not defined at a given X.
- Adds repeatable arguments for `compose(f, g, ...)` and `sum(f, g, ...)`.
Test Plan: {F6409890}
Reviewers: amckinley
Reviewed By: amckinley
Subscribers: yelirekim
Differential Revision: https://secure.phabricator.com/D20454
Summary:
Depends on D20445. Ref T13279. I'm not sure what the class tree of functions actually looks like, and I suspect it isn't really a tree, so I'm hesitant to start subclassing. Instead, try adding some `isSomethingSomething()` methods.
We have some different types of functions:
# Some functions can be evaluated anywhere, like "constant(3)", which always evaluates to 3.
# Some functions can't be evaluated anywhere, but have values everywhere in some domain. This is most interesting functions, like "number of open tasks". These functions also usually have a distinct set of interesting points, and are constant between those points (any count of anything, like "open points in project" or "tasks closed by alice", etc).
# Some functions can be evaluated almost nowhere and have only discrete values. This is most of the data we actually store, which is just "+1" when a task is opened and "-1" when a task is closed.
Soon, I'd like to be able to show ("all tasks" - "open tasks") and draw a chart of closed tasks. This is somewhat tricky because the two datasets are of the second class of function (straight lines connecting dots) but their "interesting" x values won't be the same (users don't open and close tasks every second, or at the same time).
The "subtract X Y" function will need to be able to know that `subtract "all tasks" 3` and `subtract "all tasks" "closed tasks"` evaluate slightly differently.
To make this worse, the data we actually //store// is of the third class of function (just the "derivative" of the line chart), then we accumulate it in the application after we pull it out of the database. So the code will need to know that `subtract "derivative of all tasks" "derivative of closed tasks"` is meaningless, or the UI needs to make that clear, or it needs to interpret it to mean "accumulate the derivative into a line first".
Anyway, I'll sort that out in future changes. For now, simplify the easy case of functions in class (1), where they're just actual functions.
Add "shift(function, number)" and "scale(function, number)". These are probably like "mul" and "add" but they can't take two functions -- the second value must always be a constant. Maybe these will go away in the future and become `add(function, constant(3))` or something?
Test Plan: {F6382885}
Reviewers: amckinley
Reviewed By: amckinley
Subscribers: yelirekim
Maniphest Tasks: T13279
Differential Revision: https://secure.phabricator.com/D20446
Summary:
Depends on D20444. Ref T13279. Instead of ad-hoc parsing and messages, formalize chart function arguments.
Also, add a whole lot of extra type checking.
Test Plan: Built and charted various functions with various valid and invalid argument lists, got sensible-seeming errors and results.
Reviewers: amckinley
Reviewed By: amckinley
Subscribers: yelirekim
Maniphest Tasks: T13279
Differential Revision: https://secure.phabricator.com/D20445
Summary:
Depends on D20443. Ref T13279. This is probably not terribly useful on its own, but is mostly a function which takes another function as an argument, and a step toward more useful functions like arithmetic and drawing a picture of an owl.
The only structural change here is that functions now read data parameters (domain, sample limit) using a more tailored "ChartDataQuery" instead of reading the actual axis. Mostly, I want a more cohesive representation of query state that can be easily passed to sub-functions, as here.
Test Plan: {F6382432}
Reviewers: amckinley
Reviewed By: amckinley
Subscribers: yelirekim
Maniphest Tasks: T13279
Differential Revision: https://secure.phabricator.com/D20444
