New strings.WordWrap function

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

2 files changed, 90 insertions, 0 deletions

diff --git a/strings/strings.go b/strings/strings.go
index 8c10865a..c9b029fc 100644
--- a/strings/strings.go
+++ b/strings/strings.go
@@ -4,6 +4,8 @@ import (
 	"regexp"
 	"sort"
 	"strings"
+
+	"github.com/Masterminds/goutils"
 )
 
 // Indent - indent each line of the string with the given indent string
@@ -81,3 +83,30 @@ func CamelCase(in string) string {
 	s = strings.Replace(s, string(s[0]), string(in[0]), 1)
 	return nonAlphaNum.ReplaceAllString(s, "")
 }
+
+// WordWrapOpts defines the options to apply to the WordWrap function
+type WordWrapOpts struct {
+	// The desired maximum line length in characters (defaults to 80)
+	Width uint
+
+	// Line-break sequence to insert (defaults to "\n")
+	LBSeq string
+}
+
+// applies default options
+func wwDefaults(opts WordWrapOpts) WordWrapOpts {
+	if opts.Width == 0 {
+		opts.Width = 80
+	}
+	if opts.LBSeq == "" {
+		opts.LBSeq = "\n"
+	}
+	return opts
+}
+
+// WordWrap - insert line-breaks into the string, before it reaches the given
+// width.
+func WordWrap(in string, opts WordWrapOpts) string {
+	opts = wwDefaults(opts)
+	return goutils.WrapCustom(in, int(opts.Width), opts.LBSeq, false)
+}
diff --git a/strings/strings_test.go b/strings/strings_test.go
index dfcee552..d0c6ed62 100644
--- a/strings/strings_test.go
+++ b/strings/strings_test.go
@@ -1,6 +1,7 @@
 package strings
 
 import (
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -54,3 +55,63 @@ func TestCaseFuncs(t *testing.T) {
 		assert.Equal(t, d.c, CamelCase(d.in))
 	}
 }
+
+func TestWordWrap(t *testing.T) {
+	in := "a short line that needs no wrapping"
+	assert.Equal(t, in, WordWrap(in, WordWrapOpts{Width: 40}))
+
+	in = "a short line that needs wrapping"
+	out := `a short
+line that
+needs
+wrapping`
+
+	assert.Equal(t, out, WordWrap(in, WordWrapOpts{Width: 9}))
+	in = "a short line that needs wrapping"
+	out = `a short \
+line that \
+needs \
+wrapping`
+	assert.Equal(t, out, WordWrap(in, WordWrapOpts{Width: 9, LBSeq: " \\\n"}))
+
+	out = `There shouldn't be any wrapping of long words or URLs because that would break
+things very badly. To wit:
+https://example.com/a/super-long/url/that-shouldnt-be?wrapped=for+fear+of#the-breaking-of-functionality
+should appear on its own line, regardless of the desired word-wrapping width
+that has been set.`
+	in = strings.Replace(out, "\n", " ", -1)
+	assert.Equal(t, out, WordWrap(in, WordWrapOpts{}))
+
+	// TODO: get these working - need to switch to a word-wrapping package that
+	// can handle multi-byte characters!
+	//
+	// 	out = `ΤΟΙΣ πᾶσι χρόνος καὶ καιρὸς τῷ παντὶ πράγματι ὑπὸ τὸν οὐρανόν. καιρὸς τοῦ
+	// τεκεῖν καὶ καιρὸς τοῦ ἀποθανεῖν, καιρὸς τοῦ φυτεῦσαι καὶ καιρὸς τοῦ ἐκτῖλαι τὸ
+	// πεφυτευμένον, καιρὸς τοῦ ἀποκτεῖναι καὶ καιρὸς τοῦ ἰάσασθαι, καιρὸς τοῦ
+	// καθελεῖν καὶ καιρὸς τοῦ οἰκοδομεῖν, καιρὸς τοῦ κλαῦσαι καὶ καιρὸς τοῦ γελάσαι,
+	// καιρὸς τοῦ κόψασθαι καὶ καιρὸς τοῦ ὀρχήσασθαι, καιρὸς τοῦ βαλεῖν λίθους καὶ
+	// καιρὸς τοῦ συναγαγεῖν λίθους, καιρὸς τοῦ περιλαβεῖν καὶ καιρὸς τοῦ μακρυνθῆναι
+	// ἀπὸ περιλήψεως, καιρὸς τοῦ ζητῆσαι καὶ καιρὸς τοῦ ἀπολέσαι, καιρὸς τοῦ φυλάξαι
+	// καὶ καιρὸς τοῦ ἐκβαλεῖν, καιρὸς τοῦ ρῆξαι καὶ καιρὸς τοῦ ράψαι, καιρὸς τοῦ
+	// σιγᾶν καὶ καιρὸς τοῦ λαλεῖν, καιρὸς τοῦ φιλῆσαι καὶ καιρὸς τοῦ μισῆσαι, καιρὸς
+	// πολέμου καὶ καιρὸς εἰρήνης.`
+	// 	in = strings.Replace(out, "\n", " ", -1)
+	// 	assert.Equal(t, out, WordWrap(in, WordWrapOpts{}))
+
+	// TODO: get these working - need to switch to a word-wrapping package that
+	// understands multi-byte and correctly identifies line-breaking opportunities
+	// for non-latin languages.
+	//
+	// 	out = `何事にも定まった時があります。
+	// 生まれる時、死ぬ時、植える時、収穫の時、
+	// 殺す時、病気が治る時、壊す時、やり直す時、
+	// 泣く時、笑う時、悲しむ時、踊る時、
+	// 石をばらまく時、石をかき集める時、
+	// 抱きしめる時、抱きしめない時、
+	// 何かを見つける時、物を失う時、
+	// 大切にしまっておく時、遠くに投げ捨てる時、
+	// 引き裂く時、修理する時、黙っている時、口を開く時、
+	// 愛する時、憎む時、戦う時、和解する時。`
+	// 	in = strings.Replace(out, "\n", " ", -1)
+	// 	assert.Equal(t, out, WordWrap(in, WordWrapOpts{Width: 100}))
+}