New: *Simple Diff Scanner* (closes #22).

* Highlights unified diffs, especially like the ones svn diff outputs.
* Changes to make highlighting of whole lines were necessary.
* I added two example files.

More changes:
* Added token classes :head, :delete, :insert, and :change along with styles.
* Added two new special token types: :begin_line and :end_line. They mark token groups that explicitly span whole lines and should be highlighted as such.
* The HTML encoder converts these new tokens to DIVs. May need more work.
* The Debug Encoder uses square brackets for line tokens.
* Some cleanups.

1 files changed, 104 insertions, 0 deletions

diff --git a/lib/coderay/scanners/diff.rb b/lib/coderay/scanners/diff.rb
new file mode 100644
index 0000000..d52458c
--- /dev/null
+++ b/lib/coderay/scanners/diff.rb
@@ -0,0 +1,104 @@
+module CodeRay
+module Scanners
+  
+  class Diff < Scanner
+    
+    register_for :diff
+    
+    def scan_tokens tokens, options
+      
+      line_kind = nil
+      state = :initial
+      
+      until eos?
+        kind = match = nil
+        
+        if match = scan(/\n/)
+          if line_kind
+            tokens << [:end_line, line_kind]
+            line_kind = nil
+          end
+          tokens << [match, :space]
+          next
+        end
+        
+        case state
+        
+        when :initial
+          if match = scan(/--- |\+\+\+ |=+|_+/)
+            tokens << [:begin_line, line_kind = :head]
+            tokens << [match, :head]
+            next unless match = scan(/.+/)
+            kind = :plain
+          elsif match = scan(/Index: |Property changes on: /)
+            tokens << [:begin_line, line_kind = :head]
+            tokens << [match, :head]
+            next unless match = scan(/.+/)
+            kind = :plain
+          elsif match = scan(/Added: /)
+            tokens << [:begin_line, line_kind = :head]
+            tokens << [match, :head]
+            next unless match = scan(/.+/)
+            kind = :plain
+            state = :added
+          elsif match = scan(/\\ /)
+            tokens << [:begin_line, line_kind = :change]
+            tokens << [match, :change]
+            next unless match = scan(/.+/)
+            kind = :plain
+          elsif scan(/(@@)((?>[^@\n]*))(@@)/)
+            tokens << [:begin_line, line_kind = :change]
+            tokens << [self[1], :change]
+            tokens << [self[2], :plain]
+            tokens << [self[3], :change]
+            next unless match = scan(/.+/)
+            kind = :plain
+          elsif match = scan(/\+/)
+            tokens << [:begin_line, line_kind = :insert]
+            tokens << [match, :insert]
+            next unless match = scan(/.+/)
+            kind = :plain
+          elsif match = scan(/-/)
+            tokens << [:begin_line, line_kind = :delete]
+            tokens << [match, :delete]
+            next unless match = scan(/.+/)
+            kind = :plain
+          elsif scan(/ .*/)
+            kind = :comment
+          elsif scan(/.+/)
+            tokens << [:begin_line, line_kind = :head]
+            kind = :plain
+          else
+            raise_inspect 'else case rached'
+          end
+        
+        when :added
+          if match = scan(/   \+/)
+            tokens << [:begin_line, line_kind = :insert]
+            tokens << [match, :insert]
+            next unless match = scan(/.+/)
+            kind = :plain
+          else
+            state = :initial
+            next
+          end
+        end
+        
+        match ||= matched
+        if $DEBUG and not kind
+          raise_inspect 'Error token %p in line %d' %
+            [[match, kind], line], tokens
+        end
+        raise_inspect 'Empty token', tokens unless match
+        
+        tokens << [match, kind]
+      end
+      
+      tokens << [:end_line, line_kind] if line_kind
+      tokens
+    end
+    
+  end
+  
+end
+end