Add Amount.from_number().

src/js/amount.js

@@ -65,6 +65,10 @@ Amount.json_rewrite = function (j) {
   return Amount.from_json(j).to_json();
 };
 
+Amount.from_number = function (n) {
+  return (new Amount()).parse_number(n);
+};
+
 Amount.from_json = function (j) {
   return (new Amount()).parse_json(j);
 };
@@ -624,6 +628,18 @@ Amount.prototype.parse_quality = function (q, c, i) {
   return this;
 }
 
+Amount.prototype.parse_number = function (n) {
+  this._currency    = Currency.from_json(1);
+  this._issuer      = UInt160.from_json(1);
+  this._is_negative = n < 0 ? 1 : 0;
+  this._value       = new BigInteger(this._is_negative ? -n : n);
+  this._offset      = 0;
+
+  this.canonicalize();
+
+  return this;
+};
+
 // <-> j
 Amount.prototype.parse_json = function (j) {
   if ('string' === typeof j) {

src/js/currency.js

@@ -52,6 +52,10 @@ Currency.prototype.parse_json = function (j) {
   if ("" === j || "0" === j || "XRP" === j) {
     this._value	= 0;
   }
+  else if ('number' === typeof j) {
+    // XXX This is a hack
+    this._value	= j;
+  }
   else if ('string' != typeof j || 3 !== j.length) {
     this._value	= NaN;
   }

src/js/uint160.js

@@ -37,7 +37,10 @@ UInt160.prototype.parse_json = function (j) {
   if (config.accounts && j in config.accounts)
     j = config.accounts[j].account;
 
-  if ('string' !== typeof j) {
+  if ('number' === typeof j) {
+    this._value  = new BigInteger(j);
+  }
+  else if ('string' !== typeof j) {
     this._value  = NaN;
   }
   else if (j[0] === "r") {