Merge pull request #3 from bnkamalesh/fmt-stringer-interface

Fmt stringer interface

README.md

@@ -9,10 +9,9 @@
 [![awesome-go](https://awesome.re/mentioned-badge.svg)](https://github.com/avelino/awesome-go#financial)
 
 
-## Currency v1.0.0
+## Currency v2.0.0
 
-Currency package helps you do currency computations accurately, by avoiding *_peddling_*.
-The `Currency` struct holds all the data required to define a currency.
+Currency package helps you do currency computations accurately. `Currency` struct holds all the data required to define a currency.
 
 ```
 type Currency struct {
@@ -29,6 +28,10 @@ type Currency struct {
 	// FUShare represents the no.of fractional/sub units that make up 1 main unit. e.g. ₹1 = 100 paise
 	// Number of fractional units that make up 1 unit of the main value
 	FUShare uint
+	// PrefixSymbol if true will prefix the symbol when stringified
+	PrefixSymbol bool
+	// SuffixSymbol if true will suffix the symbol when stringified
+	SuffixSymbol bool
 }
 ```
 
@@ -81,7 +84,7 @@ e.g. ₹1/- (INR 1) is to be divided by 3. There are 2 options of dividing this
 
 ### Multiple currency representations
 
-1. `c1.String(prefixSymbol bool)`, returns a string representation of the currency value. Returns string prefixed by its respective symbol if `prefixSymbol` is true
+1. `c1.String()`, returns a string representation of the currency value
 2. `c1.Float64()`, returns a float64 representation of the currency value
 
 ## Benchmarks

currency.go

@@ -48,6 +48,10 @@ type Currency struct {
 	fuDigits int `json:"fuDigits,omitempty"`
 	// magnitude is the fraction which sets the magnitude required for the rounding function
 	magnitude float64 `json:"magnitude,omitempty"`
+	// PrefixSymbol if true will add the symbol as a prefix to the string representation of currency. e.g. ₹1.5
+	PrefixSymbol bool `json:"alwaysAddPrefix,omitempty"`
+	// SuffixSymbol if true will add the symbol as a suffix to the string representation of currency. e.g. 1.5₹
+	SuffixSymbol bool `json:"alwaysAddSuffix,omitempty"`
 }
 
 // New returns a new instance of currency.
@@ -190,8 +194,7 @@ func (c *Currency) Float64() float64 {
 	return float64(c.Main) + (float64(frac) / float64(c.FUShare))
 }
 
-// String returns the currency represented as string.
-func (c *Currency) String(prefixSymbol bool) string {
+func (c *Currency) StringWithoutSymbols() string {
 	frc := c.Fractional
 	if c.Fractional < 0 {
 		frc = -frc
@@ -209,24 +212,35 @@ func (c *Currency) String(prefixSymbol bool) string {
 	if c.Fractional < 0 {
 		str = "-" + str
 	}
+	return str
+}
 
-	if prefixSymbol {
+// String returns the currency represented as string.
+func (c *Currency) String() string {
+	str := c.StringWithoutSymbols()
+
+	if c.PrefixSymbol {
 		if c.Fractional < 0 || c.Main < 0 {
 			str = strings.Replace(str, "-", "-"+c.Symbol, 1)
 		} else {
 			str = c.Symbol + str
 		}
 	}
 
+	if c.SuffixSymbol {
+		str = str + c.Symbol
+	}
+
 	return str
 }
 
 func (c *Currency) Format(s fmt.State, verb rune) {
 	switch verb {
-	// 's' verb would produce the full currency string along with its symbol. equivalent to c.String(true)
-	case 's':
+	// 's' verb would produce the full currency string along with its symbol. equivalent to c.String()
+	// 'v' - only once you add this does the fmt.Stringer seem to work, otherwise it's always printing blank
+	case 's', 'v':
 		{
-			_, _ = io.WriteString(s, c.String(true))
+			_, _ = io.WriteString(s, c.String())
 		}
 	// 'd' verb would produce the main integer part of the currency, without the symbol
 	case 'd':
@@ -240,10 +254,10 @@ func (c *Currency) Format(s fmt.State, verb rune) {
 			main := strconv.Itoa(c.Fractional)
 			_, _ = io.WriteString(s, main)
 		}
-	// 'f' verb would produce the full currency string without its symbol. equivalent to c.String(false)
+	// 'f' verb would produce the full currency string without its symbol. equivalent to c.StringWithoutSymbols()
 	case 'f':
 		{
-			_, _ = io.WriteString(s, c.String(false))
+			_, _ = io.WriteString(s, c.StringWithoutSymbols())
 		}
 	// 'y' verb would produce the currency symbol alone
 	case 'y':

currency_test.go

@@ -94,7 +94,8 @@ func TestNew(t *testing.T) {
 			t.Fail()
 		}
 
-		str := cur.String(true)
+		cur.PrefixSymbol = true
+		str := cur.String()
 		if str != nT.out.str {
 			t.Log("Expected:", nT.out.str, "got:", str)
 			t.Fail()
@@ -137,7 +138,8 @@ func TestNewFractional(t *testing.T) {
 			t.Fail()
 		}
 
-		str := cur.String(true)
+		cur.PrefixSymbol = true
+		str := cur.String()
 		if str != nT.out.str {
 			t.Log("Expected:", nT.out.str, "got:", str)
 			t.Fail()
@@ -179,7 +181,8 @@ func TestParseStr(t *testing.T) {
 			t.Fail()
 		}
 
-		str := cur.String(true)
+		cur.PrefixSymbol = true
+		str := cur.String()
 		if str != nT.out.str {
 			t.Log("Expected:", nT.out.str, "got:", str)
 			t.Fail()
@@ -221,7 +224,8 @@ func TestParseFloat64(t *testing.T) {
 			t.Fail()
 		}
 
-		str := cur.String(true)
+		cur.PrefixSymbol = true
+		str := cur.String()
 		if str != nT.out.str {
 			t.Log("Expected:", nT.out.str, "got:", str)
 			t.Fail()
@@ -245,11 +249,29 @@ func TestFormat(t *testing.T) {
 	list := []struct {
 		Verb     string
 		Expected string
+		Prefix   bool
+		Suffix   bool
 	}{
 		{
 			Verb:     "s",
+			Expected: "12.75",
+		},
+		{
+			Verb:     "s",
+			Prefix:   true,
 			Expected: "₹12.75",
 		},
+		{
+			Verb:     "s",
+			Suffix:   true,
+			Expected: "12.75₹",
+		},
+		{
+			Verb:     "s",
+			Suffix:   true,
+			Prefix:   true,
+			Expected: "₹12.75₹",
+		},
 		{
 			Verb:     "d",
 			Expected: "12",
@@ -268,6 +290,9 @@ func TestFormat(t *testing.T) {
 		},
 	}
 	for _, l := range list {
+		c.PrefixSymbol = l.Prefix
+		c.SuffixSymbol = l.Suffix
+
 		formatstr := "%" + l.Verb
 		str := fmt.Sprintf(formatstr, c)
 		if str != l.Expected {
@@ -302,15 +327,16 @@ func BenchmarkParseString(t *testing.B) {
 
 func BenchmarkString(t *testing.B) {
 	cur1, _ := New(10, 5, "INR", "₹", "paise", 100)
+	cur1.PrefixSymbol = true
 	for i := 0; i < t.N; i++ {
-		cur1.String(true)
+		cur1.String()
 	}
 }
 
 func BenchmarkStringNoPrefix(t *testing.B) {
 	cur1, _ := New(10, 5, "INR", "₹", "paise", 100)
 	for i := 0; i < t.N; i++ {
-		cur1.String(false)
+		cur1.StringWithoutSymbols()
 	}
 }
 

operations_test.go

@@ -20,7 +20,8 @@ func TestUpdateWithFractional(t *testing.T) {
 		t.Fail()
 	}
 
-	s := cur.String(true)
+	cur.PrefixSymbol = true
+	s := cur.String()
 	if s != "₹10.05" {
 		t.Log("Expected ₹10.05, got:", s)
 		t.Fail()
@@ -59,7 +60,8 @@ func TestAdd(t *testing.T) {
 		t.Fail()
 	}
 
-	str := cur1.String(true)
+	cur1.PrefixSymbol = true
+	str := cur1.String()
 	if str != "₹21.98" {
 		t.Log("Expected ₹21.98, got:", str)
 		t.Fail()
@@ -98,7 +100,8 @@ func TestAdd2(t *testing.T) {
 		t.Fail()
 	}
 
-	str := cur1.String(true)
+	cur1.PrefixSymbol = true
+	str := cur1.String()
 	if str != "₹0.00" {
 		t.Log("Expected ₹0.00, got:", str)
 		t.Fail()
@@ -136,7 +139,8 @@ func TestAdd3(t *testing.T) {
 		t.Fail()
 	}
 
-	str := cur1.String(true)
+	cur1.PrefixSymbol = true
+	str := cur1.String()
 	if str != "-₹20.50" {
 		t.Log("Expected -₹20.50, got:", str)
 		t.Fail()
@@ -168,7 +172,8 @@ func TestAddInt(t *testing.T) {
 		t.Fail()
 	}
 
-	str := cur.String(true)
+	cur.PrefixSymbol = true
+	str := cur.String()
 	if str != "₹21.09" {
 		t.Log("Expected:", "₹21.09", "got:", str)
 		t.Fail()
@@ -207,7 +212,8 @@ func TestSubtract(t *testing.T) {
 		t.Fail()
 	}
 
-	str := cur1.String(true)
+	cur1.PrefixSymbol = true
+	str := cur1.String()
 	if str != "-₹1.00" {
 		t.Log("Expected -₹1.00, got:", str)
 		t.Fail()
@@ -246,7 +252,8 @@ func TestSub2(t *testing.T) {
 		t.Fail()
 	}
 
-	str := cur1.String(true)
+	cur1.PrefixSymbol = true
+	str := cur1.String()
 	if str != "₹4.70" {
 		t.Log("Expected ₹4.70, got:", str)
 		t.Fail()
@@ -278,7 +285,8 @@ func TestSubtractInt(t *testing.T) {
 		t.Fail()
 	}
 
-	str := cur.String(true)
+	cur.PrefixSymbol = true
+	str := cur.String()
 	if str != "-₹0.09" {
 		t.Log("Expected:", "-₹0.09", "got:", str)
 		t.Fail()
@@ -310,7 +318,8 @@ func TestMultiply(t *testing.T) {
 		t.Fail()
 	}
 
-	str := cur1.String(true)
+	cur1.PrefixSymbol = true
+	str := cur1.String()
 	if str != "₹52.50" {
 		t.Log("Expected ₹52.50, got:", str)
 		t.Fail()
@@ -342,7 +351,8 @@ func TestMultiplyFloat64(t *testing.T) {
 		t.Fail()
 	}
 
-	str := cur1.String(true)
+	cur1.PrefixSymbol = true
+	str := cur1.String()
 	if str != "₹11.03" {
 		t.Log("Expected ₹11.03, got:", str)
 		t.Fail()
@@ -374,7 +384,8 @@ func TestPercent(t *testing.T) {
 		t.Fail()
 	}
 
-	str := cur2.String(true)
+	cur2.PrefixSymbol = true
+	str := cur2.String()
 	if str != "₹0.55" {
 		t.Log("Expected ₹0.55, got:", str)
 		t.Fail()
@@ -400,7 +411,8 @@ func TestDivideRetain(t *testing.T) {
 		t.Fail()
 	}
 
-	for _, split := range splits {
+	for idx := range splits {
+		split := splits[idx]
 		if split.Main != 0 {
 			t.Log("Expected", 0, "got:", split.Main)
 			t.Fail()
@@ -411,7 +423,8 @@ func TestDivideRetain(t *testing.T) {
 			t.Fail()
 		}
 
-		str := split.String(true)
+		split.PrefixSymbol = true
+		str := split.String()
 		if str != "₹0.33" {
 			t.Log("Expected:", "₹0.33", "got:", str)
 			t.Fail()
@@ -443,7 +456,8 @@ func TestDivideNoRetain(t *testing.T) {
 		t.Fail()
 	}
 
-	for _, split := range splits {
+	for idx := range splits {
+		split := splits[idx]
 		if split.Main != 0 {
 			t.Log("Expected", 0, "got:", split.Main)
 			t.Fail()
@@ -454,7 +468,8 @@ func TestDivideNoRetain(t *testing.T) {
 			t.Fail()
 		}
 
-		str := split.String(true)
+		split.PrefixSymbol = true
+		str := split.String()
 		if str != "₹0.33" && str != "₹0.34" {
 			t.Log("Expected:", "₹0.33 or ₹0.34", "got:", str)
 			t.Fail()