Add support for alt-text.

Author: ioquatix

lib/rdoc/markdown.kpeg

@@ -992,9 +992,14 @@ Strike = &{ strike? }
          "~~"
          { strike a.join }
 
-# TODO alt text support
-Image = "!" ( ExplicitLink | ReferenceLink ):a
-        { "rdoc-image:#{a[/\[(.*)\]/, 1]}" }
+Image = "!" ExplicitLink:a
+        {
+          # Extract alt text and URL
+          alt_text = a[/\{(.*?)\}/, 1] || ""
+          url = a[/\[(.*?)\]/, 1] || ""
+
+          "rdoc-image:#{url}:#{alt_text}"
+        }
 
 Link =  ExplicitLink | ReferenceLink | AutoLink
 

lib/rdoc/markup/to_html.rb

@@ -98,7 +98,12 @@ def handle_RDOCLINK url # :nodoc:
 
       gen_url CGI.escapeHTML(url), CGI.escapeHTML(text)
     when /^rdoc-image:/
-      %[<img src=\"#{CGI.escapeHTML($')}\">]
+      url, alt = $'.split(":", 2) # Split the string after "rdoc-image:" into url and alt
+      if alt
+        %[<img src="#{CGI.escapeHTML(url)}" alt="#{CGI.escapeHTML(alt)}">]
+      else
+        %[<img src="#{CGI.escapeHTML(url)}">]
+      end
     when /\Ardoc-[a-z]+:/
       CGI.escapeHTML($')
     end

test/rdoc/test_rdoc_markdown.rb

@@ -511,7 +511,7 @@ def test_parse_html_no_html
   def test_parse_image
     doc = parse "image ![alt text](path/to/image.jpg)"
 
-    expected = doc(para("image rdoc-image:path/to/image.jpg"))
+    expected = doc(para("image rdoc-image:path/to/image.jpg:alt text"))
 
     assert_equal expected, doc
   end
@@ -523,7 +523,7 @@ def test_parse_image_link
 
     expected =
       doc(
-        para('{rdoc-image:path/to/image.jpg}[http://example.com]'))
+        para('{rdoc-image:path/to/image.jpg:alt text}[http://example.com]'))
 
     assert_equal expected, doc
   end