--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/vendor/github.com/yosssi/gcss/line.go	Sun Jul 23 13:18:53 2023 +0000
@@ -0,0 +1,114 @@
+package gcss
+
+import (
+	"fmt"
+	"strings"
+)
+
+const unicodeSpace = 32
+
+const indentTop = 0
+
+// line represents a line of codes.
+type line struct {
+	no     int
+	s      string
+	indent int
+}
+
+// isEmpty returns true if the line's s is zero value.
+func (ln *line) isEmpty() bool {
+	return strings.TrimSpace(ln.s) == ""
+}
+
+// isTopIndent returns true if the line's indent is the top level.
+func (ln *line) isTopIndent() bool {
+	return ln.indent == indentTop
+}
+
+// childOf returns true if the line is a child of the parent.
+func (ln *line) childOf(parent element) (bool, error) {
+	var ok bool
+	var err error
+
+	switch pIndent := parent.Base().ln.indent; {
+	case ln.indent == pIndent+1:
+		ok = true
+	case ln.indent > pIndent+1:
+		err = fmt.Errorf("indent is invalid [line: %d]", ln.no)
+	}
+
+	return ok, err
+}
+
+// isDeclaration returns true if the line is a declaration.
+func (ln *line) isDeclaration() bool {
+	_, _, err := declarationPV(ln)
+	return err == nil
+}
+
+// isAtRule returns true if the line is an at-rule.
+func (ln *line) isAtRule() bool {
+	return strings.HasPrefix(strings.TrimSpace(ln.s), atMark)
+}
+
+// isVariable returns true if the line is a variable.
+func (ln *line) isVariable() bool {
+	if !ln.isTopIndent() {
+		return false
+	}
+
+	_, _, err := variableNV(ln)
+
+	return err == nil
+}
+
+// isMixinDeclaration returns true if the line is a mixin declaration.
+func (ln *line) isMixinDeclaration() bool {
+	if !ln.isTopIndent() {
+		return false
+	}
+
+	_, _, err := mixinNP(ln, true)
+
+	return err == nil
+}
+
+// isMixinInvocation returns true if the line is a mixin invocation.
+func (ln *line) isMixinInvocation() bool {
+	if ln.isTopIndent() {
+		return false
+	}
+
+	_, _, err := mixinNP(ln, false)
+
+	return err == nil
+}
+
+// isComment returns true if the line is a comment.
+func (ln *line) isComment() bool {
+	return strings.HasPrefix(strings.TrimSpace(ln.s), doubleSlash)
+}
+
+// newLine creates and returns a line.
+func newLine(no int, s string) *line {
+	return &line{
+		no:     no,
+		s:      s,
+		indent: indent(s),
+	}
+}
+
+// indent returns the string's indent.
+func indent(s string) int {
+	var i int
+
+	for _, b := range s {
+		if b != unicodeSpace {
+			break
+		}
+		i++
+	}
+
+	return i / 2
+}