Added Clear and renamed ctor

Author: linkdotnet

stringbuilder.go

@@ -13,7 +13,7 @@ func NewStringBuilder(initialCapacity int) *StringBuilder {
 }
 
 // Creates a new instance of the StringBuilder with a preallocated text
-func NewFromString(text string) *StringBuilder {
+func NewStringBuilderFromString(text string) *StringBuilder {
 	return &StringBuilder{
 		data:     []rune(text),
 		position: len(text),
@@ -105,6 +105,12 @@ func (s *StringBuilder) Insert(index int, text string) error {
 	return nil
 }
 
+// Removes all characters from the current instance. This sets the internal size to 0.
+// The internal array will stay the same.
+func (s *StringBuilder) Clear() {
+	s.position = 0
+}
+
 func (s *StringBuilder) grow(lenToAdd int) {
 	// Grow times 2 until lenToAdd fits
 	newLen := cap(s.data)

stringbuilder_test.go

@@ -59,15 +59,15 @@ func TestToStringEmptyBuilder(t *testing.T) {
 func TestNewFromString(t *testing.T) {
 	const expected string = "Hello"
 
-	sb := NewFromString(expected)
+	sb := NewStringBuilderFromString(expected)
 
 	if result := sb.ToString(); result != expected {
 		t.Errorf("Actual %q, Expected: %q", result, expected)
 	}
 }
 
 func TestRemovePartOfString(t *testing.T) {
-	sb := NewFromString("Hello")
+	sb := NewStringBuilderFromString("Hello")
 
 	if err := sb.Remove(3, 2); err != nil {
 		t.Errorf("Remove threw an error: %v", err)
@@ -79,31 +79,31 @@ func TestRemovePartOfString(t *testing.T) {
 }
 
 func TestRemoveWhenStartIndexOutOfBounds(t *testing.T) {
-	sb := NewFromString("Hello")
+	sb := NewStringBuilderFromString("Hello")
 
 	if err := sb.Remove(100, 1); err == nil {
 		t.Error("Should throw error but did not")
 	}
 }
 
 func TestRemoveWhenStartIndexNegative(t *testing.T) {
-	sb := NewFromString("Hello")
+	sb := NewStringBuilderFromString("Hello")
 
 	if err := sb.Remove(-1, 1); err == nil {
 		t.Error("Should throw error but did not")
 	}
 }
 
 func TestRemoveWhenLengthNegative(t *testing.T) {
-	sb := NewFromString("Hello")
+	sb := NewStringBuilderFromString("Hello")
 
 	if err := sb.Remove(1, -1); err == nil {
 		t.Error("Should throw error but did not")
 	}
 }
 
 func TestRemoveWhenEndIndexOutOfBounds(t *testing.T) {
-	sb := NewFromString("Hello")
+	sb := NewStringBuilderFromString("Hello")
 
 	if err := sb.Remove(4, 4); err == nil {
 		t.Error("Should throw error but did not")
@@ -112,7 +112,7 @@ func TestRemoveWhenEndIndexOutOfBounds(t *testing.T) {
 
 func TestRemoveWhenLengthZero(t *testing.T) {
 	const expected string = "Hello"
-	sb := NewFromString(expected)
+	sb := NewStringBuilderFromString(expected)
 
 	if err := sb.Remove(0, 0); err != nil {
 		t.Errorf("Remove threw an error: %v", err)
@@ -125,7 +125,7 @@ func TestRemoveWhenLengthZero(t *testing.T) {
 
 func TestInsertAtIndex(t *testing.T) {
 	const expected string = "Hello my dear and beautiful World"
-	sb := NewFromString("Hello World")
+	sb := NewStringBuilderFromString("Hello World")
 
 	if err := sb.Insert(5, " my dear and beautiful"); err != nil {
 		t.Errorf("Insert threw an error: %v", err)
@@ -151,3 +151,13 @@ func TestInsertShouldThrowErrirIfOutOfRange(t *testing.T) {
 		t.Error("Should throw error but did not")
 	}
 }
+
+func TestClear(t *testing.T) {
+	sb := NewStringBuilderFromString("Hello")
+
+	sb.Clear()
+
+	if result := sb.ToString(); result != "" {
+		t.Errorf("Expected empty string but did receive %v", result)
+	}
+}