2 files changed, 164 insertions, 0 deletions
diff --git a/dom/css_class.go b/dom/css_class.go
new file mode 100644
index 0000000..998dd50
--- /dev/null
+++ b/dom/css_class.go
@@ -0,0 +1,45 @@
+package dom
+
+import "strings"
+
+type ClassList map[string]struct{}
+
+func (cl ClassList) set(e Element) Element {
+	if len(cl) == 0 {
+		return e
+	}
+	classes := ""
+	for k := range cl {
+		classes += k + " "
+	}
+	classes = strings.TrimSpace(classes)
+	return e.SetAttribute("class", classes)
+}
+
+func (cl ClassList) Has(v string) bool {
+	_, ok := cl[v]
+	return ok
+}
+
+func (cl ClassList) Add(v string) ClassList {
+	cl[v] = struct{}{}
+	return cl
+}
+
+func (cl ClassList) Remove(v string) ClassList {
+	delete(cl, v)
+	return cl
+}
+
+func (cl ClassList) Toggle(v string) ClassList {
+	if cl.Has(v) {
+		cl.Remove(v)
+	} else {
+		cl.Add(v)
+	}
+	return cl
+}
+
+func NewClassList() ClassList {
+	return ClassList(make(map[string]struct{}))
+}
diff --git a/dom/html.go b/dom/html.go
new file mode 100644
index 0000000..a7dc434
--- /dev/null
+++ b/dom/html.go
@@ -0,0 +1,119 @@
+package dom
+
+import (
+	"fmt"
+	"html/template"
+)
+
+func render(tag string, attributes map[string]string, endSlash bool) template.HTML {
+	base := fmt.Sprintf(`<%s`, tag)
+	for k, v := range attributes {
+		base += fmt.Sprintf(` %s="%s"`, k, v)
+	}
+	if !endSlash {
+		return template.HTML(base + `>`)
+	}
+	return template.HTML(base + ` />`)
+}
+
+type Element interface {
+	Render() template.HTML
+	HasAttribute(string) bool
+	SetAttribute(string, string) Element
+	RemoveAttribute(string) Element
+	ClassList() ClassList
+}
+
+type LiteralElement template.HTML
+
+func (e LiteralElement) Render() template.HTML {
+	return template.HTML(e)
+}
+
+func (LiteralElement) HasAttribute(string) bool {
+	return false
+}
+
+func (e LiteralElement) SetAttribute(string, string) Element {
+	return e
+}
+
+func (e LiteralElement) RemoveAttribute(string) Element {
+	return e
+}
+
+func (e LiteralElement) ClassList() ClassList {
+	return nil
+}
+
+func NewLiteralElement(s template.HTML) LiteralElement {
+	return LiteralElement(s)
+}
+
+type VoidElement struct {
+	Tag        string
+	attributes map[string]string
+	cl         ClassList
+}
+
+func (e VoidElement) Render() template.HTML {
+	e.cl.set(e)
+	return render(e.Tag, e.attributes, true)
+}
+
+func (e VoidElement) HasAttribute(k string) bool {
+	_, ok := e.attributes[k]
+	return ok
+}
+
+func (e VoidElement) SetAttribute(k, v string) Element {
+	e.attributes[k] = v
+	return e
+}
+
+func (e VoidElement) RemoveAttribute(k string) Element {
+	delete(e.attributes, k)
+	return e
+}
+
+func (e VoidElement) ClassList() ClassList {
+	return e.cl
+}
+
+func NewVoidElement(tag string) VoidElement {
+	return VoidElement{tag, make(map[string]string), NewClassList()}
+}
+
+func NewImg(src, alt string) Element {
+	return NewVoidElement("img").SetAttribute("alt", alt).SetAttribute("src", src)
+}
+
+type ContentElement struct {
+	VoidElement
+	Contents []Element
+}
+
+func (e ContentElement) Render() template.HTML {
+	e.cl.set(e)
+	base := render(e.Tag, e.attributes, false)
+	for _, el := range e.Contents {
+		base += el.Render()
+	}
+	return base + template.HTML(fmt.Sprintf(`</%s>`, e.VoidElement.Tag))
+}
+
+func NewContentElement(tag string, contents []Element) ContentElement {
+	return ContentElement{NewVoidElement(tag), contents}
+}
+
+func NewLiteralContentElement(tag string, content template.HTML) Element {
+	return NewContentElement(tag, []Element{NewLiteralElement(content)})
+}
+
+func NewParagraph(content template.HTML) Element {
+	return NewLiteralContentElement("p", content)
+}
+
+func NewHeading(level uint, content template.HTML) Element {
+	return NewLiteralContentElement(fmt.Sprintf("h%d", level), content)
+}