The two patches described here:

http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-core/7647
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-core/7651

were never applied (as far as 1.8.6, anyway). They fix multiline 
constants and "---" (hline) in plain text files. Is it possible to get 
them in?

The patches were for 1.8.4. The second one is still correct for 1.8.6. 
The first one should be corrected for 1.8.6 as follows:

--- parsers/parse_rb.rb.bck     2007-05-13 13:04:13.000000000 -0700
+++ parsers/parse_rb.rb 2007-05-13 13:04:13.000000000 -0700
@@ -1848,9 +1848,9 @@
          case tk
          when TkSEMICOLON
            break
-        when TkLPAREN, TkfLPAREN
+        when TkLPAREN, TkfLPAREN, TkLBRACE, TkLBRACK, TkDO
            nest += 1
-        when TkRPAREN
+        when TkRPAREN, TkRBRACE, TkRBRACK, TkEND
            nest -= 1
          when TkCOMMENT
            if nest <= 0 && @scanner.lex_state == EXPR_END
@@ -1858,7 +1858,7 @@
              break
            end
          when TkNL
-          if (@scanner.lex_state == EXPR_END and nest <= 0) || 
!@scanner.continue
+           if (nest <= 0) && ((@scanner.lex_state == EXPR_END) || 
(!@scanner.continue))
              unget_tk(tk)
              break
            end

-- 
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407