FEAT: made parse's ahead being a synonym for and for better compatibility with Red

resolves: Oldes/Rebol-issues#2095

Author: Oldes

src/boot/words.reb

@@ -143,6 +143,7 @@ any
 opt
 not
 and
+ahead
 then
 remove
 insert

src/core/u-parse.c

@@ -739,6 +739,7 @@ void Print_Parse_Index(REBCNT type, REBVAL *rules, REBSER *series, REBCNT index)
 						continue;
 
 					case SYM_AND:
+					case SYM_AHEAD:
 						SET_FLAG(flags, PF_AND);
 						continue;
 

src/tests/units/parse-test.r3

@@ -65,6 +65,26 @@ Rebol [
 	--assert not parse "" [not [0 "a"]]
 ===end-group===
 
+===start-group=== "AND / AHEAD"
+;@@ https://github.com/Oldes/Rebol-issues/issues/2095
+--test-- "and"
+	--assert parse "a" [and #"a" skip]
+	--assert all [parse "abc" [#"a" and #"b" copy x to end]  x = "bc"]
+	--assert parse [1] [and integer! skip]
+	--assert parse [1 hi] [integer! and word! skip]
+	--assert all [parse [hi @bob] ['hi and ref! copy x skip] x = @bob]
+	--assert not parse "a" [and #"b" skip]
+	--assert not parse [1] [and word! skip]
+--test-- "ahead"
+	--assert parse "a" [ahead #"a" skip]
+	--assert all [parse "abc" [#"a" ahead #"b" copy x to end]  x = "bc"]
+	--assert parse [1] [ahead integer! skip]
+	--assert parse [1 hi] [integer! ahead word! skip]
+	--assert all [parse [hi @bob] ['hi ahead ref! set x skip] x = @bob]
+	--assert not parse "a" [ahead #"b" skip]
+	--assert not parse [1] [ahead word! skip]
+===end-group===
+
 
 ===start-group=== "THEN"
 --test-- "then"