preparing UriChunk to a refactoring that will let chunks decide whether they want to match or not

(not merely by specifying a regexp pattern)

app/models/chunks/uri.rb

@@ -60,7 +60,9 @@ class URIChunk < Chunk::Abstract
         "(?:\\#(#{FRAGMENT}))?"     # Optional #fragment      (\7)
   end
 
-  URI_PATTERN_REGEXP = Regexp.new(URI_PATTERN, Regexp::EXTENDED, 'N')
+  TEXTILE_SYNTAX_PREFIX = '(!)?'
+
+  URI_PATTERN_REGEXP = Regexp.new(TEXTILE_SYNTAX_PREFIX + URI_PATTERN, Regexp::EXTENDED, 'N')
 
   def self.pattern
     URI_PATTERN_REGEXP
@@ -73,12 +75,28 @@ class URIChunk < Chunk::Abstract
 
     @link_text = match_data[0]
     
-    @original_scheme, @user, @host, @port, @path, @query, @fragment = match_data[1..-1]
+    @textile_syntax, @original_scheme, @user, @host, @port, @path, @query, @fragment = 
+        match_data[1..-1]
     
+    case @textile_syntax
+    when '":'
+      # skip URL - need to refactor apply_chunk! into the chunk class itself
+    when '!'
+      # if the last char is also an exclamation, it's Textile syntax for an image; skip it
+      if @link_text[-1..-1] == '!'
+        # skip URL
+      else 
+        match_url
+      end
+    else
+      match_url
+    end
+  end
+
+  def match_url
     # If the last character matched by URI pattern is in ! or ), this may be part of the markup,
     # not a URL. We should handle it as such. It is possible to do it by a regexp, but 
     # much easier to do programmatically
-
     last_char = @link_text[-1..-1]
     if last_char == ')' or last_char == '!'
       @trailing_punctuation = last_char