FIX: mold emitting invisible chars in some cases

resolves: Oldes/Rebol-issues#2562

Author: Oldes

src/core/s-mold.c

@@ -326,7 +326,7 @@ STOID Sniff_String(REBSER *ser, REBCNT idx, REB_STRF *sf)
 static REBUNI *Emit_Uni_Char(REBUNI *up, REBUNI chr, REBOOL parened)
 {
 	if (chr >= 0x7f || chr == 0x1e) {  // non ASCII or ^ must be (00) escaped
-		if (parened || chr == 0x1e) { // do not AND with above
+		if (parened || chr <= 0xA0 || chr == 0x1e) { // do not AND with above
 			*up++ = '^';
 			*up++ = '(';
 			up = Form_Uni_Hex(up, chr);

src/tests/units/mold-test.r3

@@ -220,6 +220,15 @@ Rebol [
 ===end-group=== 
 
 
+===start-group=== "mold char!"
+	--test-- "mold invisible chars"
+		;@@ https://github.com/Oldes/Rebol-issues/issues/2562
+		for i 127 160 1 [
+			--assert all [8 = length? v: mold to char! i  v/4 = #"("]
+		]
+===end-group=== 
+
+
 ===start-group=== "mold-all"
 
 	--test-- "mold-true" --assert "true" = mold true