Use S instead of H for bi-annual dates.

H (half year) is still allowed.

src/@dates/dates.m

@@ -228,9 +228,9 @@ end % classdef
 %@test:3
 %$ % Define some dates
 %$ B1 = '1945H1';
-%$ B2 = '1950H2';
+%$ B2 = '1950S2';
 %$ B3 = '1950h1';
-%$ B4 = '1953h2';
+%$ B4 = '1953s2';
 %$
 %$ % Define expected results.
 %$ e.time = [1945*2+1; 1950*2+2; 1950*2+1; 1953*2+2];

src/utilities/convert/date2string.m

@@ -124,7 +124,7 @@ catch
 end
 
 if t(1)
-    t(2) = isequal(str, '1938H2');
+    t(2) = isequal(str, '1938S2');
 end
 
 T = all(t);

src/utilities/convert/freq2string.m

@@ -4,9 +4,9 @@ function s = freq2string(freq) % --*-- Unitary tests --*--
 % - freq  [integer]   scalar equal to 1, 2, 4, 12, or 365 (resp. annual, bi-annual, quaterly, monthly, or daily)
 %
 % OUTPUTS
-% - s     [char]      scalar equal to Y, H, Q, M, or D (resp. annual, bi-annual, quaterly, monthly, or daily)
+% - s     [char]      scalar equal to Y, S, Q, M, or D (resp. annual, bi-annual, quaterly, monthly, or daily)
 
-% Copyright © 2013-2020 Dynare Team
+% Copyright © 2013-2021 Dynare Team
 %
 % This file is part of Dynare.
 %
@@ -27,7 +27,7 @@ switch freq
   case 1
     s = 'Y';
   case 2
-    s = 'H';
+    s = 'S';
   case 4
     s = 'Q';
   case 12
@@ -54,7 +54,7 @@ end
 
 if t(1)
     t(2) = isequal(strY, 'Y');
-    t(3) = isequal(strH, 'H');
+    t(3) = isequal(strH, 'S');
     t(4) = isequal(strQ, 'Q');
     t(5) = isequal(strM, 'M');
     t(6) = isequal(strD, 'D');

src/utilities/convert/string2date.m

@@ -31,7 +31,7 @@ if isyearly(a)
 end
 
 if isbiannual(a)
-    period = cellfun(@str2double, strsplit(a, {'H','h'}));
+    period = cellfun(@str2double, strsplit(a, {'H','h','S','s'}));
     date.freq = 2;
     date.time = period(1)*2+period(2);
     return

src/utilities/is/isbiannual.m

 function b = isbiannual(str)  % --*-- Unitary tests --*--
 
-% Tests if the input can be interpreted as a bi-annual date.
+% Tests if the input can be interpreted as a bi-annual date (semester).
 %
 % INPUTS
 %  o str     string.
@@ -8,7 +8,7 @@ function b = isbiannual(str)  % --*-- Unitary tests --*--
 % OUTPUTS
 %  o b       integer scalar, equal to 1 if str can be interpreted as a bi-annual date or 0 otherwise.
 
-% Copyright (C) 2020 Dynare Team
+% Copyright © 2021 Dynare Team
 %
 % This file is part of Dynare.
 %
@@ -26,7 +26,7 @@ function b = isbiannual(str)  % --*-- Unitary tests --*--
 % along with Dynare.  If not, see <http://www.gnu.org/licenses/>.
 
 if ischar(str)
-    if isempty(regexp(str,'^-?[0-9]+[Hh][1-2]$','once'))
+    if isempty(regexp(str,'^-?[0-9]+[HhSs][1-2]$','once'))
         b = false;
     else
         b = true;
@@ -44,6 +44,8 @@ end
 %$ date_5 = '1950 azd ';
 %$ date_6 = '1950Y';
 %$ date_7 = '1950m24';
+%$ date_8 = '1950S2';
+%$ date_9 = '1950s2';
 %$
 %$ t(1) = dassert(isbiannual(date_1),true);
 %$ t(2) = dassert(isbiannual(date_2),true);
@@ -52,5 +54,7 @@ end
 %$ t(5) = dassert(isbiannual(date_5),false);
 %$ t(6) = dassert(isbiannual(date_6),false);
 %$ t(7) = dassert(isbiannual(date_7),false);
+%$ t(8) = dassert(isbiannual(date_8),true);
+%$ t(9) = dassert(isbiannual(date_9),true);
 %$ T = all(t);
 %@eof:1
\ No newline at end of file