Simple CPNumberFormatter stringFromNumber for CPNumberFormatterDecimalStyle.

Foundation/CPNumberFormatter.j

@@ -24,12 +24,85 @@
 @import <Foundation/CPString.j>
 @import <Foundation/CPFormatter.j>
 
+CPNumberFormatterNoStyle            = 0;
+CPNumberFormatterDecimalStyle       = 1;
+CPNumberFormatterCurrencyStyle      = 2;
+CPNumberFormatterPercentStyle       = 3;
+CPNumberFormatterScientificStyle    = 4;
+CPNumberFormatterSpellOutStyle      = 5;
+
+/*!
+    @ingroup foundation
+    @class CPNumberFormatter
+
+    CPNumberFormatter takes a numeric NSNumber value and formats it as text for
+    display. It also supports the converse, taking text and interpreting it as a
+    CPNumber by configurable formatting rules.
+*/
 @implementation CPNumberFormatter : CPFormatter
 {
+    CPNumberFormatterStyle  _numberStyle @accessors(property=numberStyle);
+    CPString                _perMillSymbol @accessors(property=perMillSymbol);
+}
+
+- (CPString)stringFromNumber:(CPNumber)number
+{
+    // TODO Add locale support.
+    switch(_numberStyle)
+    {
+        case CPNumberFormatterDecimalStyle:
+            var dcmn = [CPDecimalNumber numberWithFloat:number],
+                numberHandler = [CPDecimalNumberHandler decimalNumberHandlerWithRoundingMode:CPRoundPlain scale:3 raiseOnExactness:NO raiseOnOverflow:NO raiseOnUnderflow:NO raiseOnDivideByZero:YES];
+
+            dcmn = [dcmn decimalNumberByRoundingAccordingToBehavior:numberHandler];
+
+            var output = [dcmn descriptionWithLocale:nil],
+                parts = [output componentsSeparatedByString:"."], // FIXME Locale specific.
+                preFraction = parts[0],
+                fraction = parts.length > 1 ? parts[1] : "",
+                preFractionLength = [preFraction length],
+                commaPosition = 3,
+                perMillSymbol = [self _effectivePerMillSymbol];
+
+            // TODO This is just a temporary solution. Should be generalised.
+            // Add in thousands separators.
+            if (perMillSymbol)
+                while(commaPosition < [preFraction length])
+                {
+                    preFraction = [preFraction stringByReplacingCharactersInRange:CPMakeRange(commaPosition, 0) withString:perMillSymbol];
+                    commaPosition += 4;
+                }
+
+            if (fraction)
+                return preFraction + "." + fraction;
+            else
+                return preFraction;
+        default:
+            return [number description];
+    }
+}
+
+- (CPNumber)numberFromString:(CPString)string
+{
+
+}
+
+
+/*!
+    @ignore
+    Return the perMillSymbol if set, otherwise the locale default.
+*/
+- (CPString)_effectivePerMillSymbol
+{
+    if (_perMillSymbol === nil || _perMillSymbol === undefined)
+        return ","; // (FIXME US Locale specific.)
+    return _perMillSymbol;
 }
 
 @end
 
+var CPNumberFormatterStyleKey = "CPNumberFormatterStyleKey";
+
 @implementation CPNumberFormatter (CPCoding)
 
 - (id)initWithCoder:(CPCoder)aCoder
@@ -38,6 +111,7 @@
 
     if (self)
     {
+        _numberStyle = [aCoder decodeIntForKey:CPNumberFormatterStyleKey];
     }
 
     return self;
@@ -46,6 +120,8 @@
 - (void)encodeWithCoder:(CPCoder)aCoder
 {
     [super encodeWithCoder:aCoder];
+
+    [aCoder encodeInt:_numberStyle forKey:CPNumberFormatterStyleKey];
 }
 
 @end

Tests/Foundation/CPNumberFormatterTest.j

@@ -0,0 +1,19 @@
+@import <Foundation/Foundation.j>
+
+@implementation CPNumberFormatterTest : OJTestCase
+{
+}
+
+- (void)testDecimalStyle
+{
+    var numberFormatter = [[CPNumberFormatter alloc] init];
+    [numberFormatter setNumberStyle:CPNumberFormatterDecimalStyle];
+    var formattedNumberString = [numberFormatter stringFromNumber:[CPNumber numberWithInt:123]];
+    [self assert:@"123" equals:formattedNumberString];
+
+    formattedNumberString = [numberFormatter stringFromNumber:[CPNumber numberWithFloat:122344.4563]];
+    // TODO Locale support. This test is sensitive to float precision.
+    [self assert:@"122,344.456" equals:formattedNumberString];
+}
+
+@end