Add util.Find{FirstEOL LastSOL}; use it

edit/builtins.go

@@ -2,9 +2,10 @@ package edit
 
 import (
 	"fmt"
-	"strings"
 	"unicode"
 	"unicode/utf8"
+
+	"github.com/xiaq/elvish/util"
 )
 
 // Line editor builtins.
@@ -85,21 +86,14 @@ func startCommand(ed *Editor, k Key) *leReturn {
 }
 
 func killLineLeft(ed *Editor, k Key) *leReturn {
-	// Find last start of line
-	sol := strings.LastIndex(ed.line[:ed.dot], "\n") + 1
+	sol := util.FindLastSOL(ed.line[:ed.dot])
 	ed.line = ed.line[:sol] + ed.line[ed.dot:]
 	ed.dot = sol
 	return nil
 }
 
 func killLineRight(ed *Editor, k Key) *leReturn {
-	// Find next end of line
-	eol := strings.IndexRune(ed.line[ed.dot:], '\n')
-	if eol == -1 {
-		eol = len(ed.line)
-	} else {
-		eol += ed.dot
-	}
+	eol := util.FindFirstEOL(ed.line[ed.dot:]) + ed.dot
 	ed.line = ed.line[:ed.dot] + ed.line[eol:]
 	return nil
 }

util/strings.go

@@ -24,3 +24,15 @@ func FindContext(text string, pos int) (lineno, colno int, line string) {
 	line = strings.SplitN(text[p-colno:], "\n", 2)[0]
 	return
 }
+
+func FindFirstEOL(s string) int {
+	eol := strings.IndexRune(s, '\n')
+	if eol == -1 {
+		eol = len(s)
+	}
+	return eol
+}
+
+func FindLastSOL(s string) int {
+	return strings.LastIndex(s, "\n") + 1
+}