Introduce calculatable numeric types (#1432)

* Add calculalted Numeric abstraction

* Add calculated Number type

* Add some Number tests

* Typo

* Scaffold for calculated interger

* Accept broader refinements in Selective.if()

* Replace CSS Number by (fixed) calculatable ones

* Clean up parser

* Use (fixed) calculated Integers

* Remove and infer redundant second parameter of dimensions

* Make calculatable length inherits from calculatable dimensions

* Add some angle parsing tests

* Build calculatable Angle abstraction

* Spread usage of calculatable Angles

* Streamline expressions reducing

* Introduce calculatable percentage abstraction

* Remove NumberPercentage

* Use calculatable percentages

* Streamline percentage resolusion

* Clean up

* Extract API

* Clean up

* Clean up

* Extract API

* Strip down base numerics used in calculations

* Remove Math inheritance from Value

* Move value.ts back in the value directory

* Mark temporary helpers as internal

* Extract API

* Introduce Foo.Canonical abstraction

* Extract API

* Typo

Co-authored-by: Rolf Christian Jørgensen <114920418+rcj-siteimprove@users.noreply.github.com>

---------

Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Rolf Christian Jørgensen <114920418+rcj-siteimprove@users.noreply.github.com>

.changeset/brown-countries-applaud.md

@@ -0,0 +1,10 @@
+---
+"@siteimprove/alfa-style": minor
+"@siteimprove/alfa-css": minor
+---
+
+**Breaking:** New abstractions for calculatable numeric values (numbers, percentages, dimensions) are introduced and used in style properties. Currently, style properties only accept non-calculated numeric (except for some properties that already accepted calculated lengths or length-percentages and keep doing so).
+
+These abstractions are now exported from `@siteimprove/alfa-css` instead of the old abstractions which didn't accept calculations. In order to keep the functionalities of the old abstractions, replace `Foo` (`Number`, `Length`, …) with `Foo.Fixed`.
+
+The new abstractions come with a `#resolve()` method which resolve any remaining calculation and returns a `Fixed` value. These methods need various resolvers argument depending on the precise abstraction (e.g. `Length#resolve` needs to know how to resolve relative lengths into `px`).

.changeset/cold-tables-sing.md

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+---
+"@siteimprove/alfa-css": minor
+---
+
+**Breaking:** Math expression converters (`.toLength`, …) now return a `Result<T, string>` instead of an `option<T>`.

.changeset/fair-needles-compare.md

@@ -0,0 +1,5 @@
+---
+"@siteimprove/alfa-css": minor
+---
+
+**Breaking:** The redundant second type parameter (Unit category) of Dimensions has been removed and is now automatically inferred from the first parameter (type string representation).

.changeset/gold-pens-shave.md

@@ -2,10 +2,7 @@
 "@siteimprove/alfa-css": minor
 ---
 
-**Breaking:** `Math.resolve` has been renamed `Math.resolve2`.
-This is a temporary change to accommodate for the new `resolve` method on parent class `Value`.
-
-**Breaking:** `Math.resolve2` now returns a `Result<Numeric, string>` instead of an `Option`.
+**Breaking:** `Math.resolve` now returns a `Result<Numeric, string>` instead of an `Option`.
 Invalid expressions return an error message.
 
-**Breaking:** No resolver is needed for `Math.resolve2` on `Number` expressions.
+**Breaking:** No resolver is needed for `Math.resolve` on `Number` expressions.

.changeset/hip-baboons-applaud.md

@@ -0,0 +1,5 @@
+---
+"@siteimprove/alfa-css": minor
+---
+
+**Added:** Most CSS value types now export a `Foo.Canonical` type which is the canonical representation of the type with calculation resolved, relative values absolutized, and dimensions converted to their canonical units. The `Canonical` type is normally the one used to represent conputed values of style propreties.

.changeset/odd-dancers-rush.md

@@ -0,0 +1,7 @@
+---
+"@siteimprove/alfa-selective": minor
+---
+
+**Added:** `Selective.if()` now accepts any refinement and will refine to the intersection of its result and the value in the associated right side.
+
+This allows use cases like `Selective.of<A | B>(foo).if(isBOrC, bar => …)` to correctly refine `bar` to a `B` instead of defaulting to the `Predicate` overload that wouldn't refine anything.

.changeset/rotten-birds-pay.md

@@ -0,0 +1,5 @@
+---
+"@siteimprove/alfa-style": minor
+---
+
+**Breaking:** the `NumberPercentage` abstraction, which doesn't exist in CSS, has been removed.

.changeset/serious-snails-switch.md

@@ -0,0 +1,5 @@
+---
+"@siteimprove/alfa-style": minor
+---
+
+**Breaking:** The `Resolver.percentage` helper has been removed. Instead, the `Percentage#resolve(base)` method (from `@siteimprove/alfa-css`) provides the same functionality.