Add MAYBE-UNCOMPUTABLE modifier to trigger.

src/calendar.c

@@ -1325,6 +1325,9 @@ static int DoCalRem(ParsePtr p, int col)
     if (trig.typ == SAT_TYPE) {
 	r=DoSatRemind(&trig, &tim, p);
 	if (r) {
+            if (r == E_CANT_TRIG && trig.maybe_uncomputable) {
+                r = OK;
+            }
 	    FreeTrig(&trig);
 	    if (r == E_EXPIRED) return OK;
 	    return r;
@@ -1369,6 +1372,9 @@ static int DoCalRem(ParsePtr p, int col)
 	/* Calculate the trigger date */
 	jul = ComputeTrigger(trig.scanfrom, &trig, &tim, &r, 1);
 	if (r) {
+            if (r == E_CANT_TRIG && trig.maybe_uncomputable) {
+                r = OK;
+            }
 	    FreeTrig(&trig);
 	    return r;
 	}

src/dorem.c

@@ -81,6 +81,9 @@ int DoRem(ParsePtr p)
 	PurgeEchoLine("%s\n", CurLine);
 	r=DoSatRemind(&trig, &tim, p);
 	if (r) {
+            if (r == E_CANT_TRIG && trig.maybe_uncomputable) {
+                r = OK;
+            }
 	    FreeTrig(&trig);
 	    if (r == E_EXPIRED) return OK;
 	    return r;
@@ -134,6 +137,9 @@ int DoRem(ParsePtr p)
 		PurgeEchoLine("%s: %s\n", "#!P! Problem calculating trigger date", ErrMsg[r]);
 		PurgeEchoLine("%s\n", CurLine);
 	    }
+            if (r == E_CANT_TRIG && trig.maybe_uncomputable) {
+                r = OK;
+            }
 	    FreeTrig(&trig);
 	    return r;
 	}
@@ -219,6 +225,7 @@ int ParseRem(ParsePtr s, Trigger *trig, TimeTrig *tim, int save_in_globals)
     trig->duration_days = 0;
     trig->eventstart = NO_TIME;
     trig->eventduration = NO_TIME;
+    trig->maybe_uncomputable = 0;
     DBufInit(&(trig->tags));
     trig->passthru[0] = 0;
     tim->ttime = NO_TIME;
@@ -276,6 +283,10 @@ int ParseRem(ParsePtr s, Trigger *trig, TimeTrig *tim, int save_in_globals)
 	    trig->m = tok.val;
 	    break;
 
+        case T_MaybeUncomputable:
+            trig->maybe_uncomputable = 1;
+            break;
+
 	case T_Skip:
 	    DBufFree(&buf);
 	    if (trig->skip != NO_SKIP) return E_SKIP_ERR;

src/funcs.c

@@ -2917,6 +2917,10 @@ FEvalTrig(func_info *info)
 	}
 	jul = ComputeTrigger(scanfrom, &trig, &tim, &r, 0);
     }
+    if (r == E_CANT_TRIG && trig.maybe_uncomputable) {
+        r = 0;
+        jul = -1;
+    }
     FreeTrig(&trig);
     if (r) return r;
     if (jul < 0) {

src/main.c

@@ -813,9 +813,11 @@ int DoIfTrig(ParsePtr p)
 	if (trig.typ != NO_TYPE) return E_PARSE_ERR;
 	jul = ComputeTrigger(trig.scanfrom, &trig, &tim, &r, 1);
 	if (r) {
-	    if (!Hush || r != E_RUN_DISABLED) {
-		Eprint("%s", ErrMsg[r]);
-	    }
+            if (r != E_CANT_TRIG || !trig.maybe_uncomputable) {
+                if (!Hush || r != E_RUN_DISABLED) {
+                    Eprint("%s", ErrMsg[r]);
+                }
+            }
 	    syndrome = IF_TRUE | BEFORE_ELSE;
 	}
 	else {

src/token.c

@@ -67,6 +67,7 @@ Token TokArray[] = {
     { "june",		3,	T_Month,	5 },
     { "march",		3,	T_Month,	2 },
     { "may",		3,	T_Month,	4 },
+    { "maybe-uncomputable", 5,  T_MaybeUncomputable, 0},
     { "monday",		3,	T_WkDay,	0 },
     { "msf",		3,	T_RemType,	MSF_TYPE },
     { "msg",		3,	T_RemType,	MSG_TYPE },

src/types.h

@@ -73,6 +73,7 @@ typedef struct {
     int duration_days;           /* Duration converted to days to search */
     int eventstart;              /* Original event start (datetime) */
     int eventduration;           /* Original event duration (minutes) */
+    int maybe_uncomputable;      /* Suppress "can't compute trigger" warnings */
     char sched[VAR_NAME_LEN+1];  /* Scheduling function */
     char warn[VAR_NAME_LEN+1];   /* Warning function    */
     char omitfunc[VAR_NAME_LEN+1]; /* OMITFUNC function */
@@ -171,7 +172,8 @@ enum TokTypes
   T_Duration,
   T_LongTime,
   T_OmitFunc,
-  T_Through
+  T_Through,
+  T_MaybeUncomputable
 };
 
 /* The structure of a token */