Patch - Support tag exclusion filtering

- Now supports "-tag" in filters to filter out tasks that do not
  have the specified tag (thanks to Chris Pride).
- Added unit tests to prevent regression.
- Updated the filter docs to include examples.

ChangeLog

@@ -14,7 +14,10 @@
    part of the description, despite what they otherwise might mean.
  + Removed support for the obsolete task file format 1 (never released).
  + Fixed bug that allowed blank annotations to be added (thanks to Bruce
-   Dillahunty),
+   Dillahunty).
+ + Supports negative tag filters, so that (task list +foo -bar) now filters
+   tasks that have the "foo" tag, but do not have the "bar" tag (thanks to
+   Chris Pride).
 
 ------ old releases ------------------------------
 

html/filter.html

@@ -76,6 +76,13 @@
                 <p>
                   Lists only tasks with the "shopping" tag.
                 </p>
+
+                <code><pre>% task list +shopping -gift</pre></code>
+
+                <p>
+                  Lists tasks that have the "shopping" tag, but do not have the
+                  "gift" tag.
+                </p>
               </div>
 
               <br />

html/task.html

@@ -144,7 +144,10 @@
                       part of the description, despite what they otherwise might mean.
                   <li>Removed support for the obsolete task file format 1 (never released).
                   <li>Fixed bug that allowed blank annotations to be added (thanks to Bruce
-                      Dillahunty),
+                      Dillahunty).
+                  <li>Supports negative tag filters, so that (task list +foo -bar) now filters
+                      tasks that have the "foo" tag, but do not have the "bar" tag (thanks to
+                      Chris Pride).
                 </ul>
 
                 <p>

src/report.cpp

@@ -108,6 +108,9 @@ void filter (std::vector<T>& all, T& task)
   std::vector <std::string> tagList;
   task.getTags (tagList);
 
+  std::vector <std::string> removeTagList;
+  task.getRemoveTags (removeTagList);
+
   // Get all the attributes to match against.
   std::map <std::string, std::string> attrList;
   task.getAttributes (attrList);
@@ -180,7 +183,15 @@ void filter (std::vector<T>& all, T& task)
             ++matches;
 
         if (matches == tagList.size ())
-          filtered.push_back (refTask);
+        {
+          matches = 0;
+          for (unsigned int t = 0; t < removeTagList.size (); ++t)
+            if (refTask.hasTag (removeTagList[t]))
+              ++matches;
+
+          if (matches == 0)
+            filtered.push_back (refTask);
+        }
       }
     }
   }

src/tests/filter.t

@@ -28,7 +28,7 @@
 
 use strict;
 use warnings;
-use Test::More tests => 108;
+use Test::More tests => 129;
 
 # Create the rc file.
 if (open my $fh, '>', 'filter.rc')
@@ -110,6 +110,33 @@ like   ($output, qr/five/,  'g5');
 unlike ($output, qr/six/,   'g6');
 unlike ($output, qr/seven/, 'g7');
 
+$output = qx{../task rc:filter.rc list -tag};
+unlike ($output, qr/one/,   'g1');
+like   ($output, qr/two/,   'g2');
+like   ($output, qr/three/, 'g3');
+like   ($output, qr/four/,  'g4');
+unlike ($output, qr/five/,  'g5');
+like   ($output, qr/six/,   'g6');
+like   ($output, qr/seven/, 'g7');
+
+$output = qx{../task rc:filter.rc list -missing};
+like   ($output, qr/one/,   'g1');
+like   ($output, qr/two/,   'g2');
+like   ($output, qr/three/, 'g3');
+like   ($output, qr/four/,  'g4');
+like   ($output, qr/five/,  'g5');
+like   ($output, qr/six/,   'g6');
+like   ($output, qr/seven/, 'g7');
+
+$output = qx{../task rc:filter.rc list +tag -tag};
+unlike ($output, qr/one/,   'g1');
+unlike ($output, qr/two/,   'g2');
+unlike ($output, qr/three/, 'g3');
+unlike ($output, qr/four/,  'g4');
+unlike ($output, qr/five/,  'g5');
+unlike ($output, qr/six/,   'g6');
+unlike ($output, qr/seven/, 'g7');
+
 $output = qx{../task rc:filter.rc list project:A priority:H};
 like   ($output, qr/one/,   'h1');
 like   ($output, qr/two/,   'h2');