Add trigbase() built-in function.

contrib/remind-conf-mode/remind-conf-mode.el

@@ -145,7 +145,7 @@
          "$NumTrig" "$October" "$On" "$OnceFile" "$ParseUntriggered" "$Pm"
          "$PrefixLineNo" "$PSCal" "$RunOff" "$Saturday" "$September"
          "$SimpleCal" "$SortByDate" "$SortByPrio" "$SortByTime" "$SubsIndent"
-         "$Sunday" "$SuppressImplicitWarnings" "$SuppressLRM" "$SysInclude" "$T" "$Td"
+         "$Sunday" "$SuppressImplicitWarnings" "$SuppressLRM" "$SysInclude" "$T" "$Tb" "$Td"
          "$TerminalBackground" "$Thursday" "$TimeSep" "$TimetIs64bit" "$Tm" "$Today"
          "$Tomorrow" "$Tt" "$Tuesday" "$Tw" "$Ty" "$U" "$Ud" "$Um"
          "$UntimedFirst" "$Use256Colors" "$UseBGVTColors" "$UseTrueColors"
@@ -176,7 +176,7 @@
          "ostype" "pad" "plural" "psmoon" "psshade" "realcurrent" "realnow"
          "realtoday" "rows" "sgn" "shell" "shellescape" "slide" "soleq"
          "stdout" "strlen" "substr" "sunrise" "sunset" "time" "timepart"
-         "timezone" "today" "trig" "trigback" "trigdate" "trigdatetime"
+         "timezone" "today" "trig" "trigback" "trigbase" "trigdate" "trigdatetime"
          "trigdelta" "trigduration" "trigeventduration" "trigeventstart"
          "trigfrom" "trigger" "triginfo" "trigpriority" "trigrep"
          "trigscanfrom" "trigtags" "trigtime" "trigtimedelta" "trigtimerep"

man/remind.1.in

@@ -3029,6 +3029,9 @@ this installation.
 .B $T (read-only, DATE type)
 Exactly equivalent to \fBtrigdate()\fR.  (See BUILT-IN FUNCTIONS.)
 .TP
+.B $Tb (read-only, DATE type)
+Exactly equivalent to \fBtrigbase()\fR.  (See BUILT-IN FUNCTIONS.)
+.TP
 .B $Td (read-only)
 Equivalent to \fBday(trigdate())\fR.
 .TP
@@ -4388,6 +4391,25 @@ Returns the "back" amount of the last \fBREM\fR or \fBIFTRIG\fR command.
 Returns a positive integer N if the "back" is of the form -N, or a negative
 integer if it is of the form --N.  If there is no "back", then returns 0.
 .TP
+.B trigbase()
+Returns the "base" date of the last \fBREM\fR or \fBIFTRIG\fR command.
+If the trigger specification includes \fIall three\fR of day, month
+and year, then the base date is the date formed from those components.
+If the trigger specification lacks one of those components, then 0 is
+returned.
+.RS
+.PP
+Here is an example of how \fBtrigbase()\fR might be used:
+.PP
+.nf
+        REM 2025-05-05 *7 UNTIL 2025-05-26 \\
+           MSG Meeting: week #[(trigdate() - trigbase())/7+1]
+.fi
+.PP
+On 2025-05-05, it would print: "Meeting: week #1".  On 2025-05-12,
+it would print: "Meeting: week #2" and so on.
+.RE
+.TP
 .B trigdelta()
 Returns the "delta" amount of the last \fBREM\fR or \fBIFTRIG\fR command.
 Returns a positive integer N if the "delta" is of the form +N, or a negative

src/calendar.c

@@ -2464,6 +2464,10 @@ void WriteJSONTrigger(Trigger const *t, int include_tags, int today)
     if (t->rep) {
         PrintJSONKeyPairInt("rep", t->rep);
     }
+    if (t->d != NO_DAY && t->m != NO_MON && t->y != NO_YR) {
+        printf("\"trigbase\":\"%04d-%02d-%-2d\",",
+               t->y, t->m+1, t->d);
+    }
     /* Local omit is an array of days from 0=monday to 6=sunday.
        We convert to array of strings */
     if (t->localomit != NO_WD) {

src/funcs.c

@@ -170,6 +170,7 @@ static int FTimezone       (func_info *);
 static int FToday          (func_info *);
 static int FTrig           (func_info *);
 static int FTrigback       (func_info *);
+static int FTrigbase       (func_info *info);
 static int FTrigdate       (func_info *);
 static int FTrigdatetime   (func_info *);
 static int FTrigdelta      (func_info *);
@@ -340,6 +341,7 @@ BuiltinFunc Func[] = {
     {   "today",        0,      0,      0,          FToday, NULL },
     {   "trig",         0,      NO_MAX, 0,          FTrig, NULL },
     {   "trigback",     0,      0,      0,          FTrigback, NULL },
+    {   "trigbase",     0,      0,      0,          FTrigbase, NULL },
     {   "trigdate",     0,      0,      0,          FTrigdate, NULL },
     {   "trigdatetime", 0,      0,      0,          FTrigdatetime, NULL },
     {   "trigdelta",    0,      0,      0,          FTrigdelta, NULL },
@@ -1753,6 +1755,20 @@ static int FTrigdate(func_info *info)
     return OK;
 }
 
+static int FTrigbase(func_info *info)
+{
+    if (LastTrigger.d != NO_DAY &&
+        LastTrigger.m != NO_MON &&
+        LastTrigger.y != NO_YR) {
+        RetVal.type = DATE_TYPE;
+        RETVAL = DSE(LastTrigger.y, LastTrigger.m, LastTrigger.d);
+    } else {
+        RetVal.type = INT_TYPE;
+        RETVAL = 0;
+    }
+    return OK;
+}
+
 static int FTrigback(func_info *info)
 {
     RetVal.type = INT_TYPE;

src/var.c

@@ -254,6 +254,22 @@ static int trig_date_func(int do_set, Value *val)
     }
     return OK;
 }
+
+static int trig_base_func(int do_set, Value *val)
+{
+    UNUSED(do_set);
+    if (LastTrigger.d != NO_DAY &&
+        LastTrigger.m != NO_MON &&
+        LastTrigger.y != NO_YR) {
+        val->type = DATE_TYPE;
+        val->v.val = DSE(LastTrigger.y, LastTrigger.m, LastTrigger.d);
+    } else {
+        val->type = INT_TYPE;
+        val->v.val = 0;
+    }
+    return OK;
+}
+
 static int trig_day_func(int do_set, Value *val)
 {
     int y, m, d;
@@ -994,6 +1010,7 @@ static SysVar SysVarArr[] = {
     {"SuppressLRM",    1,  INT_TYPE,     &SuppressLRM,         0,      1 },
     {"SysInclude",     0,  STR_TYPE,     &SysDir,              0,      0 },
     {"T",              0,  SPECIAL_TYPE, trig_date_func,       0,      0 },
+    {"Tb",             0,  SPECIAL_TYPE, trig_base_func,       0,      0 },
     {"Td",             0,  SPECIAL_TYPE, trig_day_func,        0,      0 },
     {"TerminalBackground", 0, SPECIAL_TYPE,  terminal_bg_func, 0,      0 },
     {"Thursday",       1,  TRANS_TYPE,   "Thursday",           0,      0 },

tests/test.cmp

@@ -2818,6 +2818,7 @@ Variable  Value
 $SuppressImplicitWarnings  0           [0, 1]
              $SuppressLRM  0           [0, 1]
                        $T  0
+                      $Tb  0
                       $Td  -1
       $TerminalBackground  -1
                 $Thursday  "Thursday"
@@ -16516,6 +16517,8 @@ DEBUG -x
 
 DEBUG -e
 ../tests/test.rem(1581): eval(): Too many recursive function calls
+Base: 1991-02-09
+Base: 1991-02-09
 Variable hash table statistics:
   Entries: 100143; Buckets: 87719; Non-empty Buckets: 66301
   Maxlen: 5; Minlen: 0; Avglen: 1.142; Stddev: 0.878; Avg nonempty len: 1.510
@@ -24539,6 +24542,7 @@ timezone
 today
 trig
 trigback
+trigbase
 trigdate
 trigdatetime
 trigdelta
@@ -24660,6 +24664,7 @@ $SuppressImplicitWarnings
 $SuppressLRM
 $SysInclude
 $T
+$Tb
 $Td
 $TerminalBackground
 $Thursday

tests/test.rem

@@ -1580,6 +1580,10 @@ DEBUG -e
 set a "eval(a)"
 set a eval(a)
 
+# trigbase()
+REM 9 Feb 1991 *7 MSG Base: [trigbase()]
+REM 9 Feb 1991 *1 MSG Base: [$Tb]
+
 # Output expression-node stats
 DEBUG +h