add wildcards (*, ?, [...])

- unquoted * ? and [...] (including [!...]) are expanded to the
  matching file names, sorted, per path component
- hidden files only match if the pattern starts with a dot, a trailing /
  only matches directories, a pattern without match is kept as is
- quoted or escaped characters and values of variables are never
  expanded
- redirections to a pattern must match exactly one file
- completion escapes * ? [ and $ in file names

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

main_test.go

@@ -1514,6 +1514,10 @@ func TestTokenize_Operators(t *testing.T) {
 			t.Errorf("tokenize(%q) returned error: %v", tc.input, err)
 			continue
 		}
+		// Patterns are tested in TestTokenize_Patterns
+		for i := range got {
+			got[i].pattern, got[i].glob = "", false
+		}
 		if !reflect.DeepEqual(got, tc.want) {
 			t.Errorf("tokenize(%q) = %+v, want %+v", tc.input, got, tc.want)
 		}
@@ -1620,3 +1624,109 @@ func TestExecInput_RedirectionErrors(t *testing.T) {
 		t.Error("file f must not be created for a bad file descriptor")
 	}
 }
+
+func TestTokenize_Patterns(t *testing.T) {
+	t.Setenv("GOSH_GLOB", "*.go")
+	tests := []struct {
+		input   string
+		pattern string
+		glob    bool
+	}{
+		{"*.go", "*.go", true},
+		{"a?c", "a?c", true},
+		{"[ab].go", "[ab].go", true},
+		{"[!a].go", "[^a].go", true},
+		{"plain", "plain", false},
+		// Quoted, escaped and expanded characters are literal
+		{`"*.go"`, `\*.go`, false},
+		{`'*'.go`, `\*.go`, false},
+		{`\*.go`, `\*.go`, false},
+		{`"x"*`, `x*`, true},
+		{"$GOSH_GLOB", `\*.go`, false},
+		{`'['!a].go`, `\[!a].go`, false},
+	}
+	for _, tc := range tests {
+		tokens, err := tokenize(tc.input)
+		if err != nil || len(tokens) != 1 {
+			t.Errorf("tokenize(%q) = %+v, %v", tc.input, tokens, err)
+			continue
+		}
+		if tokens[0].pattern != tc.pattern || tokens[0].glob != tc.glob {
+			t.Errorf("tokenize(%q): pattern %q, glob %v; want %q, %v",
+				tc.input, tokens[0].pattern, tokens[0].glob, tc.pattern, tc.glob)
+		}
+	}
+}
+
+func TestExpandGlob(t *testing.T) {
+	origDir, _ := os.Getwd()
+	defer os.Chdir(origDir)
+	dir := t.TempDir()
+	os.Chdir(dir)
+	for _, d := range []string{"sub/deep", "other"} {
+		os.MkdirAll(d, 0755)
+	}
+	for _, f := range []string{"a.go", "b.go", "c.txt", ".hidden.go", "with space.go", "[x].go", "sub/s1.go", "sub/deep/d.go", "other/o.go"} {
+		os.WriteFile(f, nil, 0644)
+	}
+
+	tests := []struct {
+		pattern string
+		want    []string
+	}{
+		{"*.go", []string{"[x].go", "a.go", "b.go", "with space.go"}},
+		{".*.go", []string{".hidden.go"}},
+		{"?.go", []string{"a.go", "b.go"}},
+		{"[ab].go", []string{"a.go", "b.go"}},
+		{"[^a].go", []string{"b.go"}},
+		{"*/*.go", []string{"other/o.go", "sub/s1.go"}},
+		{"*/", []string{"other/", "sub/"}},
+		{"sub/*/*.go", []string{"sub/deep/d.go"}},
+		{"./c*", []string{"./c.txt"}},
+		{dir + "/c*", []string{dir + "/c.txt"}},
+		{`\[x\].go`, []string{"[x].go"}},
+		{"*.xyz", nil},
+		{"[", nil},
+	}
+	for _, tc := range tests {
+		if got := expandGlob(tc.pattern); !reflect.DeepEqual(got, tc.want) {
+			t.Errorf("expandGlob(%q) = %q, want %q", tc.pattern, got, tc.want)
+		}
+	}
+}
+
+func TestExecInput_Wildcards(t *testing.T) {
+	origDir, _ := os.Getwd()
+	defer os.Chdir(origDir)
+	dir := t.TempDir()
+	os.Chdir(dir)
+	for _, f := range []string{"a.go", "b.go", "c.txt"} {
+		os.WriteFile(f, []byte(f+"\n"), 0644)
+	}
+
+	tests := []struct {
+		input string
+		want  string
+	}{
+		{"echo *.go > out", "a.go b.go\n"},
+		{"cat *.go > out", "a.go\nb.go\n"},
+		// No match: the word is passed on unchanged, like in sh
+		{"echo *.xyz > out", "*.xyz\n"},
+		{`echo "*.go" '?.go' \*.go > out`, "*.go ?.go *.go\n"},
+		// A redirection to a pattern with a single match uses that file
+		{"echo hi > *.txt; cat c.txt > out", "hi\n"},
+	}
+	for _, tc := range tests {
+		if err := execInput(tc.input); err != nil {
+			t.Errorf("execInput(%q) returned error: %v", tc.input, err)
+		}
+		if got, _ := os.ReadFile("out"); string(got) != tc.want {
+			t.Errorf("%q: got %q, want %q", tc.input, got, tc.want)
+		}
+	}
+
+	err := execInput("echo hi > *.go")
+	if err == nil || err.Error() != "*.go: ambiguous redirect" {
+		t.Errorf("expected ambiguous redirect error, got %v", err)
+	}
+}