Refactor rendering code

This refactoring simplifies some originally quirky parts of rendering
code while also adding support for rendering emphasized text (handled by
the same routine the ordinary text already is).

internal/gemini/renderer.go

@@ -18,8 +18,6 @@
 package gemini
 
 import (
-	"bufio"
-	"bytes"
 	"fmt"
 	"io"
 	"strings"
@@ -65,46 +63,17 @@ func (r Renderer) link(w io.Writer, node *ast.Link, entering bool) {
 	if entering {
 		w.Write(linkPrefix)
 		w.Write(node.Destination)
-		for _, child := range node.Children {
-			if l := child.AsLeaf(); l != nil {
-				w.Write(space)
-				w.Write(l.Literal)
-			}
-		}
-	}
-}
-
-func (r Renderer) linkText(w io.Writer, node *ast.Link) {
-	for _, text := range node.Children {
-		// TODO: Renderer.linkText: link can contain subblocks
-		if l := text.AsLeaf(); l != nil {
-			w.Write(l.Literal)
-		}
-	}
-}
-
-func (r Renderer) imageText(w io.Writer, node *ast.Image) {
-	for _, text := range node.Children {
-		// TODO: Renderer.imageText: link can contain subblocks
-		if l := text.AsLeaf(); l != nil {
-			w.Write(l.Literal)
-		}
+		w.Write(space)
+		r.text(w, node)
 	}
 }
 
 func (r Renderer) image(w io.Writer, node *ast.Image, entering bool) {
 	if entering {
 		w.Write(linkPrefix)
 		w.Write(node.Destination)
-		for _, sub := range node.Container.Children {
-			if l := sub.AsLeaf(); l != nil {
-				// TODO: Renderer.image: Markdown technically allows for
-				// links inside image titles, yet to think out how to
-				// render that :thinking:
-				w.Write(space)
-				w.Write(l.Literal)
-			}
-		}
+		w.Write(space)
+		r.text(w, node)
 	}
 }
 
@@ -113,16 +82,8 @@ func (r Renderer) blockquote(w io.Writer, node *ast.BlockQuote, entering bool) {
 	// ideally to be merged with paragraph
 	if entering {
 		if para, ok := node.Children[0].(*ast.Paragraph); ok {
-			for _, subnode := range para.Children {
-				if l := subnode.AsLeaf(); l != nil {
-					reader := bufio.NewScanner(bytes.NewBuffer(l.Literal))
-					for reader.Scan() {
-						w.Write(quotePrefix)
-						w.Write(reader.Bytes())
-						w.Write(lineBreak)
-					}
-				}
-			}
+			w.Write(quotePrefix)
+			r.text(w, para)
 		}
 	}
 }
@@ -178,23 +139,14 @@ func (r Renderer) paragraph(w io.Writer, node *ast.Paragraph, entering bool) (no
 		for _, child := range children {
 			// only render links text in the paragraph if they're
 			// combined with some other text on page
-			if link, ok := child.(*ast.Link); ok {
-				if !onlyElement {
-					r.linkText(w, link)
-				}
-				linkStack = append(linkStack, link)
-			}
-			if image, ok := child.(*ast.Image); ok {
+			switch child := child.(type) {
+			case *ast.Link, *ast.Image:
 				if !onlyElement {
-					r.imageText(w, image)
+					r.text(w, child)
 				}
-				linkStack = append(linkStack, image)
-			}
-			if text, ok := child.(*ast.Text); ok {
-				r.text(w, text)
-			}
-			if inlineBlock, ok := child.(*ast.Code); ok {
-				r.text(w, inlineBlock)
+				linkStack = append(linkStack, child)
+			case *ast.Text, *ast.Code, *ast.Emph, *ast.Strong, *ast.Del:
+				r.text(w, child)
 			}
 		}
 		if !onlyElementIsLink {
@@ -250,10 +202,7 @@ func (r Renderer) list(w io.Writer, node *ast.List, level int) {
 			}
 			para, ok := item.Children[0].(*ast.Paragraph)
 			if ok {
-				text, ok := para.Children[0].(*ast.Text)
-				if ok {
-					r.text(w, text)
-				}
+				r.text(w, para)
 			}
 			w.Write(lineBreak)
 			if l >= 2 {
@@ -270,6 +219,12 @@ func (r Renderer) text(w io.Writer, node ast.Node) {
 		// replace all newlines in text with spaces, allowing for soft
 		// wrapping; this is recommended as per Gemini spec p. 5.4.1
 		w.Write([]byte(strings.ReplaceAll(string(node.Literal), "\n", " ")))
+		return
+	}
+	if node := node.AsContainer(); node != nil {
+		for _, child := range node.Children {
+			r.text(w, child)
+		}
 	}
 }