Review for changes to specification for Unified NumberFormat

.gitignore

@@ -40,3 +40,6 @@ jspm_packages
 yarn.lock
 package-lock.json
 npm-shrinkwrap.json
+
+
+out.html

README.md

@@ -1,19 +1,127 @@
 Intl.NumberFormat Unified API Proposal
 ======================================
 
-## Motivation
+## Background / Motivation
 
-There are many requests for adding number-formatting-related features to ECMA 402.  A few of them include:
+There are many requests for adding number-formatting-related features to ECMA 402. These include:
 
-- tc39/ecma402#200
-- tc39/ecma402#186
-- tc39/ecma402#164
-- tc39/ecma402#163
-- tc39/ecma402#95
-- tc39/ecma402#91
-- tc39/ecma402#37
-- tc39/ecma402#32
+- [Expose narrow currency symbol](https://github.com/tc39/ecma402/issues/200) -- Section I
+- [Add currency accounting format](https://github.com/tc39/ecma402/issues/186) -- Section IV
+- [Add scientific notation](https://github.com/tc39/ecma402/issues/164) -- Section III
+- [Add option to force sign](https://github.com/tc39/ecma402/issues/163) -- Section IV
+- [Add compact decimal notation](https://github.com/tc39/ecma402/issues/37) -- Section III
+- [Add measure unit formatting](https://github.com/tc39/ecma402/issues/32) -- Section II
 
-Rather than complicate `Intl` with more subclasses with heavilly overlapping functionality, this proposal is to restructure the spec of `Intl.NumberFormat` to make it more easilly support additional features in a "unified" way.
+These features are important to both end users and to Google.  Since most of these features require carrying along large amounts of locale data for proper i18n support, exposing these features via a JavaScript API reduces bandwidth and lowers the barrier to entry for i18n best practices.
+
+Rather than complicate `Intl` with more constructors with heavilly overlapping functionality, this proposal is to restructure the spec of `Intl.NumberFormat` to make it more easilly support additional features in a "unified" way.
+
+Additional background: [Unified API for number formatting](https://github.com/tc39/ecma402/issues/215)
+
+## I. Spec Cleanup
+
+Certain sections of the spec have been refactored with the following objectives:
+
+- Fix https://github.com/tc39/ecma402/issues/238 (currency long name has dependency on plural form, and the currency long name pattern has dependency on currencyWidth).
+- Move pattern resolution out of the constructor to keep all internal fields of NumberFormat locale-agnostic, making it easier to reason about behavior in the format method.
+
+In addition, one missing option is added to the existing `currencyDisplay` setting: "narrowSymbol", which uses the CLDR narrow-format symbol.
+
+## II. Measure Units
+
+Units of measurement can be formatted as follows:
+
+```javascript
+(9.81).toLocaleString("en-US", {
+    style: "unit",
+    unit: "acceleration-meter-per-second-squared",
+    unitDisplay: "short"
+});
+// ==> "9.81 m/s²"
+```
+
+The syntax was discussed in #3.
+
+- `style` receives the string value "unit"
+- `unit` receives a string measure unit identifier, defined in [UTS #35](http://unicode.org/reports/tr35/tr35-general.html#Unit_Elements).  See also the [full list of unit identifiers](https://unicode.org/repos/cldr/tags/latest/common/validity/unit.xml).
+- `unitDisplay`, named after the corresponding setting for currencies, `currencyDisplay`, takes either "narrow", "short", or "long".
+
+## III. Scientific and Compact Notation
+
+Scientific and compact notation are represented by the new option `notation` and can be formatted as follows:
+
+```javascript
+(987654321).toLocaleString("en-US", {
+    notation: "scientific"
+});
+// ==> 9.877E8
+
+(987654321).toLocaleString("en-US", {
+    notation: "engineering"
+});
+// ==> 987.7E6
+
+(987654321).toLocaleString("en-US", {
+    notation: "compact",
+    compactDisplay: "long"
+});
+// ==> 987.7 million
+```
+
+The syntax was discussed in #5.
+
+- `notation` takes either "scientific", "engineering", "compact", or "plain"
+- `compactDisplay`, used only when `notation` is "compact", takes either "short" or "long"
+
+Rounding-related settings (min/max integer/fraction digits) are applied after the number is scaled according to the chosen notation.
+
+Notation styles are allowed to be combined with other options.  (ICU supports this.)
+
+```javascript
+(299792458).toLocaleString("en-US", {
+    notation: "scientific",
+    minimumFractionDigits: 2,
+    maximumFractionDigits: 2,
+    style: "unit",
+    unit: "speed-meter-per-second"
+});
+// ==> 3.00E8 m/s
+```
+
+## IV. Sign Display
+
+The sign can be displayed on positive numbers:
+
+```javascript
+(55).toLocaleString("en-US", {
+    signDisplay: "always"
+});
+// ==> +55
+```
+
+Currency accounting sign display is also supported via a new option:
+
+```javascript
+(-55).toLocaleString("en-US", {
+    style: "currency",
+    currency: "USD",
+    currencySignDisplay: "accounting"
+});
+// ==> ($55.00)
+```
+
+The syntax was discussed in #6.
+
+- `signDisplay` takes either "auto", "always", "never", or "except-zero"
+- `currencySignDisplay` takes either "standard" or "accounting"
+
+As usual, this may be combined with other options.
+
+```javascript
+(0.55).toLocaleString("en-US", {
+    style: "percent",
+    signDisplay: "except-zero"
+});
+// ==> +55%
+```
 
-Background: tc39/ecma402#215