Unsets "no vote" for ALL and ANY, won't return them

src/boot/natives.r

@@ -30,12 +30,12 @@ also: native [
 ]
 
 all: native [
-	{Shortcut AND. Evaluates and returns at the first FALSE or NONE.}
+	{Shortcut AND. Returns NONE vs. TRUE (or last evaluation if it was TRUE?)}
 	block [block!] {Block of expressions}
 ]
 
 any: native [
-	{Shortcut OR. Evaluates and returns the first value that is not FALSE or NONE.}
+	{Shortcut OR, ignores unsets. Returns the first TRUE? result, or NONE.}
 	block [block!] {Block of expressions}
 ]
 

src/core/n-control.c

@@ -251,23 +251,39 @@ enum {
 **
 */	REBNATIVE(all)
 /*
+**	ALL is effectively Rebol's "short-circuit AND".  Unsets do not vote either
+**	true or false...they are ignored.
+**
+**	To offer a more generically useful result than just TRUE or FALSE, it will
+**	use as a "truthy" value whatever the last evaluation in the chain was.  If
+**	there was no last value, but no conditionally false instance hit to break
+**	the chain, as in `all []` or `all [1 2 ()]`...it will return TRUE.
+**
+**	(Note: It would become a more costly operation to retain the last truthy
+**	value to return 2 in the case of `all [1 2 ()`]`, just to say it could.
+**	The overhead would undermine the raw efficiency of the operation.)
+**
+**	For the "falsy" value, ALL uses a NONE! rather than logic FALSE.  It's a
+**	historical design decision which has some benefits, but perhaps some
+**	drawbacks to those wishing to use it on logic values and stay in the
+**	logic domain.  (`all [true true]` => true, `all [false true]` is NONE!).
+**
 ***********************************************************************/
 {
 	REBSER *block = VAL_SERIES(D_ARG(1));
 	REBCNT index = VAL_INDEX(D_ARG(1));
 
-	// Default result for 'all []'
 	SET_TRUE(D_OUT);
 
 	while (index < SERIES_TAIL(block)) {
 		index = Do_Next_May_Throw(D_OUT, block, index);
 		if (index == THROWN_FLAG) return R_OUT_IS_THROWN;
 
-		if (IS_CONDITIONAL_FALSE(D_OUT)) {
-			SET_TRASH_SAFE(D_OUT);
-			return R_NONE;
-		}
+		if (IS_CONDITIONAL_FALSE(D_OUT)) return R_NONE;
 	}
+
+	if (IS_UNSET(D_OUT)) return R_TRUE;
+
 	return R_OUT;
 }
 
@@ -276,6 +292,18 @@ enum {
 **
 */	REBNATIVE(any)
 /*
+**	ANY is effectively Rebol's "short-circuit OR".  Unsets do not vote either
+**	true or false...they are ignored.
+**
+**	See ALL's notes about returning the last truthy value or NONE! (vs. FALSE)
+**
+**	The base case of `any []` is NONE! and not TRUE.  This might seem strange
+**	given that `all []` is TRUE.  But this ties more into what the questions
+**	they are used to ask about in practice: "Were all of these things not
+**	false?" as opposed to "Were any of these things true?"  It is also the
+**	case that `FALSE OR X OR Y` matches with `TRUE AND X AND Y` as the
+**	"seed" for not affecting the chain.
+**
 ***********************************************************************/
 {
 	REBSER *block = VAL_SERIES(D_ARG(1));
@@ -285,7 +313,7 @@ enum {
 		index = Do_Next_May_Throw(D_OUT, block, index);
 		if (index == THROWN_FLAG) return R_OUT_IS_THROWN;
 
-		if (!IS_CONDITIONAL_FALSE(D_OUT) && !IS_UNSET(D_OUT)) return R_OUT;
+		if (IS_CONDITIONAL_TRUE(D_OUT)) return R_OUT;
 	}
 
 	return R_NONE;

src/core/n-loop.c

@@ -382,7 +382,10 @@ typedef enum {
 	Val_Init_Object(D_ARG(1), frame); // keep GC safe
 	Val_Init_Block(D_ARG(3), body); // keep GC safe
 
-	SET_NONE(D_OUT); // Default result to NONE if the loop does not run
+	if (mode == LOOP_EVERY)
+		SET_TRUE(D_OUT); // Default output is TRUE, to match ALL MAP-EACH
+	else
+		SET_NONE(D_OUT); // !!! Loops may set default to not set in future
 
 	if (mode == LOOP_MAP_EACH) {
 		// Must be managed *and* saved...because we are accumulating results
@@ -566,13 +569,7 @@ typedef enum {
 			if (!IS_UNSET(D_OUT)) Append_Value(out, D_OUT);
 			break;
 		case LOOP_EVERY:
-			if (every_true) {
-				// !!! This currently treats UNSET! as true, which ALL
-				// effectively does right now.  That's likely a bad idea.
-				// When ALL changes, so should this.
-				//
-				every_true = IS_CONDITIONAL_TRUE(D_OUT);
-			}
+			every_true = every_true && IS_CONDITIONAL_TRUE(D_OUT);
 			break;
 		default:
 			assert(FALSE);
@@ -634,10 +631,13 @@ skip_hidden: ;
 
 		// Result is the cumulative TRUE? state of all the input (with any
 		// unsets taken out of the consideration).  The last TRUE? input
-		// if all valid and NONE! otherwise.  (Like ALL.)  If the loop
-		// never runs, `every_true` will be TRUE *but* D_OUT will be NONE!
-		if (!every_true)
-			SET_NONE(D_OUT);
+		// if all valid and NONE! otherwise.  (Like ALL.)
+		if (!every_true) return R_NONE;
+
+		// We want to act like `ALL MAP-EACH ...`, hence we effectively ignore
+		// unsets and return TRUE if the last evaluation leaves an unset.
+		if (IS_UNSET(D_OUT)) return R_TRUE;
+
 		return R_OUT;
 
 	default:

src/include/sys-value.h

@@ -823,11 +823,13 @@ struct Reb_Position
 // Conditional truth and falsehood allows an interpretation where a NONE! is
 // a FALSE value.  These macros (like many others in the codebase) capture
 // their parameters multiple times, so multiple evaluations can happen!
+//
+// Unsets are neither conditionally true nor conditionally false.
 
 #define IS_CONDITIONAL_FALSE(v) \
 	(IS_NONE(v) || (IS_LOGIC(v) && !VAL_LOGIC(v)))
 #define IS_CONDITIONAL_TRUE(v) \
-	!IS_CONDITIONAL_FALSE(v)
+	(!IS_UNSET(v) && !IS_CONDITIONAL_FALSE(v))
 
 
 /***********************************************************************