Added the possibility to instantiate empty quaterly, monthly or weekly dynDate...

Added the possibility to instantiate empty quaterly, monthly or weekly dynDate objects. Added unitary test.

matlab/@dynDate/dynDate.m

@@ -75,6 +75,7 @@ switch nargin
     return
   case 1
     if ischar(a)% Weekly, Monthly or Quaterly data.
+        if length(a)>1
             quaterly = findstr('Q',a);
             monthly  = findstr('M',a);
             weekly   = findstr('W',a);
@@ -103,20 +104,36 @@ switch nargin
                     date.time(2) = 1;
                 end
             end
+        else
+            switch a
+              case 'Q'
+                date.freq = 4;
+              case 'M'
+                date.freq = 12;
+              case 'W'
+                date.freq = 52;
+              otherwise
+                % Yearly data are assumed.
+                date.freq = 1;
+            end
+        end
     elseif isa(a,'dynDate') % If input argument is a dynDate object then do a copy.
         date = a;
-    else% If b is not a string then yearly data are assumed.
+    else
+        if isequal(length(a),1)
+            % If b is not a string then yearly data are assumed.
             date.freq = 1;
             date.time(1) = a;
             date.time(2) = 1;
+        else
+            error('dynDate:: Can''t instantiate the class, wrong calling sequence!')
+        end            
     end
   otherwise
     error('dynDate:: Can''t instantiate the class, wrong calling sequence!')
 end
 
 %@test:1
-%$ addpath ../matlab
-%$
 %$ % Define some dates
 %$ date_1 = 1950;
 %$ date_2 = '1950Q2';
@@ -156,3 +173,19 @@ end
 %$ t(10)= dyn_assert(d5.freq,e_freq_5);
 %$ T = all(t);
 %@eof:1
+
+%@test:2
+%$ % Instatiate an empty objects for quaterly, monthly and weekly dates.
+%$ qq = dynDate('Q');
+%$ mm = dynDate('M');
+%$ ww = dynDate('W');
+%$
+%$ % Check the results.
+%$ t(1) = dyn_assert(qq.freq,4);
+%$ t(2) = dyn_assert(mm.freq,12);
+%$ t(3) = dyn_assert(ww.freq,52);
+%$ t(4) = dyn_assert(all(isnan(qq.time)),1);
+%$ t(5) = dyn_assert(all(isnan(mm.time)),1);
+%$ t(6) = dyn_assert(all(isnan(ww.time)),1);
+%$ T = all(t);
+%@eof:1
\ No newline at end of file