Add ParseComment option to trim comments

README.md

@@ -42,6 +42,13 @@ args, err := p.Parse("./foo `echo $SHELL`")
 // args should be ["./foo", "/bin/bash"]
 ```
 
+```go
+p := shellwords.NewParser()
+p.ParseComment = true
+args, err := p.Parse("./foo # comment")
+// args should be ["./foo"]
+```
+
 # Thanks
 
 This is based on cpan module [Parse::CommandLine](https://metacpan.org/pod/Parse::CommandLine).

shellwords.go

@@ -11,6 +11,7 @@ import (
 var (
 	ParseEnv      bool = false
 	ParseBacktick bool = false
+	ParseComment  bool = false
 )
 
 func isSpace(r rune) bool {
@@ -97,6 +98,7 @@ func replaceEnv(getenv func(string) string, s string) string {
 type Parser struct {
 	ParseEnv      bool
 	ParseBacktick bool
+	ParseComment  bool
 	Position      int
 	Dir           string
 
@@ -109,6 +111,7 @@ func NewParser() *Parser {
 	return &Parser{
 		ParseEnv:      ParseEnv,
 		ParseBacktick: ParseBacktick,
+		ParseComment:  ParseComment,
 		Position:      0,
 		Dir:           "",
 	}
@@ -125,7 +128,7 @@ const (
 func (p *Parser) Parse(line string) ([]string, error) {
 	args := []string{}
 	buf := ""
-	var escaped, doubleQuoted, singleQuoted, backQuote, dollarQuote bool
+	var escaped, doubleQuoted, singleQuoted, backQuote, dollarQuote, comment bool
 	backtick := ""
 
 	pos := -1
@@ -135,6 +138,14 @@ func (p *Parser) Parse(line string) ([]string, error) {
 loop:
 	for _, r := range line {
 		i++
+
+		if comment {
+			if r == '\n' {
+				comment = false
+			}
+			continue
+		}
+
 		if escaped {
 			if r == 't' {
 				r = '\t'
@@ -254,6 +265,11 @@ loop:
 				pos = i
 				break loop
 			}
+		case '#':
+			if p.ParseComment && len(buf) == 0 && !(escaped || singleQuoted || doubleQuoted) {
+				comment = true
+				continue loop
+			}
 		}
 
 		got = argSingle

shellwords_test.go

@@ -10,10 +10,12 @@ import (
 	"testing"
 )
 
-var testcases = []struct {
+type testcase struct {
 	line     string
 	expected []string
-}{
+}
+
+var testcases = []testcase{
 	{``, []string{}},
 	{`""`, []string{``}},
 	{`''`, []string{``}},
@@ -53,6 +55,30 @@ func TestSimple(t *testing.T) {
 	}
 }
 
+func TestComment(t *testing.T) {
+	allCases := append(testcases, []testcase{
+		{"# comment", []string{}},
+		{"foo not#comment", []string{"foo", "not#comment"}},
+		{`foo "bar # baz" # comment`, []string{"foo", "bar # baz"}},
+		{"foo \"bar # baz\" # comment\nfoo\nbar # baz",
+			[]string{"foo", "bar # baz", "foo", "bar"}},
+		{"echo '# list all files' # line\\ncomment\n# whole line comment\nls -al '#' # more comment",
+			[]string{"echo", "# list all files", "ls", "-al", "#"}},
+	}...)
+
+	parser := NewParser()
+	parser.ParseComment = true
+	for _, testcase := range allCases {
+		args, err := parser.Parse(testcase.line)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if !reflect.DeepEqual(args, testcase.expected) {
+			t.Fatalf("Expected %#v for %q, but %#v:", testcase.expected, testcase.line, args)
+		}
+	}
+}
+
 func TestError(t *testing.T) {
 	_, err := Parse("foo '")
 	if err == nil {