132 lines
2.5 KiB
Go
132 lines
2.5 KiB
Go
package hatmill
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import "io"
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//go:generate go run ./internal/codegen/codegen.go -input htmldefs.json -output htmldefs.go -package hatmill
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// Term represents a fragment of HTML markup, and is one of EmptyElement, ParentElement, or Text.
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type Term interface {
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io.WriterTo
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// isHtml is a no-op method to prevent external Term implementations, because
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// Go doesn't have sum types.
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isHtml()
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}
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// writeStringsTo attempts to write the strings in ss to w, incrementing n by the
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// number of bytes written.
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func writeStringsTo(w io.Writer, n *int64, ss ...string) error {
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for _, s := range ss {
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nCurr, err := io.WriteString(w, s)
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*n += int64(nCurr)
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if err != nil {
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return err
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}
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}
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return nil
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}
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type Attrib struct {
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Key string
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Value string
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}
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func (a Attrib) WriteTo(w io.Writer) (n int64, err error) {
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err = writeStringsTo(w, &n, a.Key)
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if err != nil {
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return
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}
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if a.Value != "" {
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err = writeStringsTo(w, &n, "='", a.Value, "'")
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}
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return
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}
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type EmptyElement struct {
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TagName string
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Attribs []Attrib
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}
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func (EmptyElement) isHtml() {}
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func (e EmptyElement) WriteTo(w io.Writer) (n int64, err error) {
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err = writeStringsTo(w, &n, "<", e.TagName)
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if err != nil {
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return
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}
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for _, attrib := range e.Attribs {
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err = writeStringsTo(w, &n, " ")
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if err != nil {
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return
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}
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var nCurr int64
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nCurr, err = attrib.WriteTo(w)
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n += int64(nCurr)
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if err != nil {
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return
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}
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}
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err = writeStringsTo(w, &n, ">")
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return
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}
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type ParentElement struct {
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EmptyElement
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Children []Term
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}
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func (e *ParentElement) isHtml() {}
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func (e *ParentElement) WriteTo(w io.Writer) (n int64, err error) {
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n, err = e.EmptyElement.WriteTo(w)
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if err != nil {
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return
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}
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for _, child := range e.Children {
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var nCurr int64
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nCurr, err = child.WriteTo(w)
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n += int64(nCurr)
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if err != nil {
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return
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}
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}
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err = writeStringsTo(w, &n, "</", e.TagName, ">")
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return
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}
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type Text string
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func (Text) isHtml() {}
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func (t Text) WriteTo(w io.Writer) (n int64, err error) {
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err = writeStringsTo(w, &n, string(t))
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return
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}
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// WriteDocument writes an HTML5 doctype declaration, followed by root.
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// root should probably be an <html> element.
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func WriteDocument(w io.Writer, root *ParentElement) (n int64, err error) {
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err = writeStringsTo(w, &n, "<!DOCTYPE html>")
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if err != nil {
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return
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}
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var nroot int64
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nroot, err = root.WriteTo(w)
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n += nroot
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return
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}
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// Data creates an attribute of the form "data-suffix='value'".
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func Data(suffix, value string) Attrib {
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return Attrib{
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Key: "data-" + suffix,
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Value: value,
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}
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}
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