remove currencySystem member (#694)

* Remove `currencySystem` member * Editorial: add note about digital currencies
w3c · May 1, 2018 · 6b2aebc · 6b2aebc
1 parent dbcbe9e
commit 6b2aebc
Showing 1 changed file with 43 additions and 50 deletions.
diff --git a/index.html b/index.html
@@ -120,12 +120,6 @@ <h2>
  before proceeding along the W3C Recommendation track.
  </p>
  <ul>
- <li>
- <a data-lt=
- "PaymentCurrencyAmount.currencySystem">currencySystem</a> (see
- <a href="https://github.com/w3c/payment-request/issues/617">issue
- 617</a>).
- </li>
  <li data-link-for="PaymentItem">
  <a>PaymentItem</a>'s <a>type</a> member and the
  <a>PaymentItemType</a> enum (see <a href=
@@ -1407,56 +1401,63 @@ <h2>
  dictionary PaymentCurrencyAmount {
  required DOMString currency;
  required DOMString value;
- // Note: currencySystem is "at risk" of being removed!
- DOMString currencySystem = "urn:iso:std:iso:4217";
  };
  </pre>
  <p>
  A <a>PaymentCurrencyAmount</a> dictionary is used to supply monetary
  amounts.
  </p>
- <div class="issue atrisk">
- <p>
- This feature has been marked "<a>at risk</a>". If you'd like for this
- feature to remain in the specification, please describe your use case
- in <a href="https://github.com/w3c/payment-request/issues/490">issue
- 490</a>.
- </p>
- <dl>
- <dt>
- <dfn>currencySystem</dfn> member
- </dt>
- <dd>
- A URL that indicates the currency system that the <a>currency</a>
- identifier belongs to. By default, the value is
- "<code>urn:iso:std:iso:4217</code>" indicating that <a>currency</a>
- is defined by [[!ISO4217]] (for example, <code>USD</code> for US
- Dollars).
- </dd>
- </dl>
- </div>
  <dl>
  <dt>
  <dfn>currency</dfn> member
  </dt>
  <dd>
  <p>
- A string containing a currency identifier. The value of
- <a>currency</a> can be any string that is valid within the currency
- system indicated by <a>currencySystem</a>.
- </p>
- <p>
- When using [[!ISO4217]], all <a data-cite=
+ A [[!ISO4217]] <a data-cite=
  "!ecma-402#sec-iswellformedcurrencycode">well-formed</a> 3-letter
- alphabetic codes are allowed (i.e., the numeric codes are not
- supported). Their canonical form is upper case. However, the set of
- combinations of currency code for which localized currency symbols
- are available is implementation dependent. Where a localized
- currency symbol is not available, a user agent SHOULD use U+00A4
- (¤) for formatting. User agents MAY format the display of the
- <a>currency</a> member to adhere to OS conventions (e.g., for
- localization purposes).
+ alphabetic code (i.e., the numeric codes are not supported). Their
+ canonical form is upper case. However, the set of combinations of
+ currency code for which localized currency symbols are available is
+ implementation dependent. Where a localized currency symbol is not
+ available, a user agent SHOULD use U+00A4 (¤) for formatting. User
+ agents MAY format the display of the <a>currency</a> member to
+ adhere to OS conventions (e.g., for localization purposes).
  </p>
+ <div class="note" title=
+ "Digital currencies and ISO 4217 currency codes">
+ <p>
+ User agents implementing this specification enforce [[ISO4217]]'s
+ 3-letter codes format via ECMAScript’s <a data-cite=
+ "!ecma-402#sec-iswellformedcurrencycode">isWellFormedCurrencyCode</a>
+ abstract operation, which is invoked as part of the <a>check and
+ canonicalize amount</a> algorithm. When a code does not adhere to
+ the [[ISO4217]] defined format, a <a>RangeError</a> is thrown.
+ </p>
+ <p>
+ Current implementations will therefore allow the use of
+ well-formed currency codes that are not part of the official
+ [[ISO4217]] list (e.g., XBT, XRP, etc.). If the provided code is
+ a currency that the browser knows how to display, then an
+ implementation will generally display the appropriate currency
+ symbol in the user interface (e.g., "USD" is shown as "$", "GBP"
+ is "£", and the non-standard "XBT" could be shown as "Ƀ"). When a
+ code cannot be matched, the specification recommends browsers
+ show a scarab "¤".
+ </p>
+ <p>
+ Efforts are underway at ISO to account for digital currencies,
+ which may result in an update to the [[ISO4217]] registry or an
+ entirely new registry. The community expects this will resolve
+ ambiguities that have crept in through the use of non-standard
+ 3-letter codes; for example, does "BTC" refer to Bitcoin or to a
+ future Bhutan currency? At the time of publication, it remains
+ unclear what form this evolution will take, or even the time
+ frame in which the work will be completed. The W3C Web Payments
+ Working Group is liaising with ISO so that, in the future,
+ revisions to this specification remain compatible with relevant
+ ISO registries.
+ </p>
+ </div>
  </dd>
  <dt>
  <dfn>value</dfn> member
@@ -1506,11 +1507,6 @@ <h3>
  steps:
  </p>
  <ol data-link-for="PaymentCurrencyAmount">
- <li data-tests=
- "PaymentCurrencyAmount/currencySystem-member.https.html">If
- <var>amount</var>.<a>currencySystem</a> is not
- "<code>urn:iso:std:iso:4217</code>", throw a <a>TypeError</a>.
- </li>
  <li>Let <var>isValidCurrency</var> be the result of calling
  <a data-cite=
  "!ecma-402#sec-iswellformedcurrencycode">IsWellFormedCurrencyCode</a>
@@ -1536,9 +1532,6 @@ <h3>
  steps:
  </p>
  <ol data-link-for="PaymentCurrencyAmount">
- <li>If <var>total</var>.<a>currencySystem</a> is not
- "<code>urn:iso:std:iso:4217</code>", terminate this algorithm.
- </li>
  <li>
  <a>Check and canonicalize amount</a> <var>amount</var>. Rethrow any
  exceptions.