--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/vendor/github.com/yosssi/gcss/declaration.go	Sun Jul 23 13:18:53 2023 +0000
@@ -0,0 +1,109 @@
+package gcss
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"strings"
+)
+
+// declaration represents a declaration of CSS.
+type declaration struct {
+	elementBase
+	property string
+	value    string
+}
+
+// WriteTo writes the declaration to the writer.
+func (dec *declaration) WriteTo(w io.Writer) (int64, error) {
+	return dec.writeTo(w, nil)
+}
+
+// writeTo writes the declaration to the writer.
+func (dec *declaration) writeTo(w io.Writer, params map[string]string) (int64, error) {
+	bf := new(bytes.Buffer)
+
+	bf.WriteString(dec.property)
+	bf.WriteString(colon)
+
+	for i, v := range strings.Split(dec.value, space) {
+		if i > 0 {
+			bf.WriteString(space)
+		}
+
+		for j, w := range strings.Split(v, comma) {
+			if j > 0 {
+				bf.WriteString(comma)
+			}
+
+			if strings.HasPrefix(w, dollarMark) {
+				// Writing to the bytes.Buffer never returns an error.
+				dec.writeParamTo(bf, strings.TrimPrefix(w, dollarMark), params)
+			} else {
+				bf.WriteString(w)
+			}
+		}
+	}
+
+	bf.WriteString(semicolon)
+
+	n, err := w.Write(bf.Bytes())
+
+	return int64(n), err
+}
+
+// writeParam writes the param to the writer.
+func (dec *declaration) writeParamTo(w io.Writer, name string, params map[string]string) (int64, error) {
+	if s, ok := params[name]; ok {
+		if strings.HasPrefix(s, dollarMark) {
+			if v, ok := dec.Context().vars[strings.TrimPrefix(s, dollarMark)]; ok {
+				return v.WriteTo(w)
+			}
+			return 0, nil
+		}
+
+		n, err := w.Write([]byte(s))
+		return int64(n), err
+	}
+
+	if v, ok := dec.Context().vars[name]; ok {
+		return v.WriteTo(w)
+	}
+
+	return 0, nil
+}
+
+// declarationPV extracts a declaration property and value
+// from the line.
+func declarationPV(ln *line) (string, string, error) {
+	pv := strings.SplitN(strings.TrimSpace(ln.s), space, 2)
+
+	if len(pv) < 2 {
+		return "", "", fmt.Errorf("declaration's property and value should be divided by a space [line: %d]", ln.no)
+	}
+
+	if !strings.HasSuffix(pv[0], colon) {
+		return "", "", fmt.Errorf("property should end with a colon [line: %d]", ln.no)
+	}
+
+	return strings.TrimSuffix(pv[0], colon), pv[1], nil
+}
+
+// newDeclaration creates and returns a declaration.
+func newDeclaration(ln *line, parent element) (*declaration, error) {
+	property, value, err := declarationPV(ln)
+
+	if err != nil {
+		return nil, err
+	}
+
+	if strings.HasSuffix(value, semicolon) {
+		return nil, fmt.Errorf("declaration must not end with %q [line: %d]", semicolon, ln.no)
+	}
+
+	return &declaration{
+		elementBase: newElementBase(ln, parent),
+		property:    property,
+		value:       value,
+	}, nil
+}