Add CutLongWords option to Wrapper (#13)

Author: bbrks

wrapper.go

@@ -46,9 +46,12 @@ type Wrapper struct {
 	TrimInputSuffix string
 
 	// StripTrailingNewline can be set to true if you want the trailing
-	// newline to be removed from the return vailue.
+	// newline to be removed from the return value.
 	// Default: false
 	StripTrailingNewline bool
+
+	// CutLongWords will cause a hard-wrap in the middle of a word if the word's length exceeds the given limit.
+	CutLongWords bool
 }
 
 // NewWrapper returns a new instance of a Wrapper initialised with defaults.
@@ -98,15 +101,24 @@ func (w Wrapper) line(s string, limit int) string {
 	// Find the index of the last breakpoint within the limit.
 	i := strings.LastIndexAny(s[:limit+1], w.Breakpoints)
 
-	// Can't wrap within the limit, wrap at the next breakpoint instead.
+	breakpointWidth := 1
+
+	// Can't wrap within the limit
 	if i < 0 {
-		i = strings.IndexAny(s, w.Breakpoints)
-		// Nothing left to do!
-		if i < 0 {
-			return w.OutputLinePrefix + s + w.OutputLineSuffix
+		if w.CutLongWords {
+			// wrap at the limit
+			i = limit
+			breakpointWidth = 0
+		} else {
+			// wrap at the next breakpoint instead
+			i = strings.IndexAny(s, w.Breakpoints)
+			// Nothing left to do!
+			if i < 0 {
+				return w.OutputLinePrefix + s + w.OutputLineSuffix
+			}
 		}
 	}
 
 	// Recurse until we have nothing left to do.
-	return w.OutputLinePrefix + s[:i] + w.OutputLineSuffix + w.Newline + w.line(s[i+1:], limit)
+	return w.OutputLinePrefix + s[:i] + w.OutputLineSuffix + w.Newline + w.line(s[i+breakpointWidth:], limit)
 }

wrapper_test.go

@@ -1,6 +1,7 @@
 package wrap_test
 
 import (
+	"strconv"
 	"strings"
 	"testing"
 	"unicode/utf8"
@@ -63,3 +64,44 @@ func TestWrapper_Wrap(t *testing.T) {
 
 	}
 }
+
+func TestWrapper_Wrap_CutLongWords(t *testing.T) {
+	const limit = 8
+
+	tests := []struct {
+		input    string
+		expected string
+	}{
+		{
+			input: "A short woooord",
+			expected: `A short
+woooord`,
+		},
+		{
+			input: "A perfect wooooord",
+			expected: `A
+perfect
+wooooord`,
+		},
+		{
+			input: "A long wooooooooooooord",
+			expected: `A long
+wooooooo
+oooooord`,
+		},
+	}
+
+	for i, test := range tests {
+		t.Run(strconv.FormatInt(int64(i), 10), func(t *testing.T) {
+			w := wrap.NewWrapper()
+			w.CutLongWords = true
+			w.StripTrailingNewline = true
+
+			actual := w.Wrap(test.input, limit)
+
+			if actual != test.expected {
+				t.Errorf("expected %q but got %q", test.expected, actual)
+			}
+		})
+	}
+}