FEAT: replaced mezzanine with with a lightweight and faster native version

Author: Oldes

src/core/n-data.c

@@ -515,6 +515,28 @@ static int Check_Char_Range(REBVAL *val, REBINT limit)
 }
 
 
+/***********************************************************************
+**
+*/	REBNATIVE(with)
+/*
+//  with: native [
+//		"Evaluates a block binded to the specified context"
+//		context [object! module! port!] "A reference to the target context"
+//		body    [block!]      "A code to be evaluated"
+//  ]
+***********************************************************************/
+{
+	REBSER *frame = VAL_OBJ_FRAME(D_ARG(1));
+	REBSER *body  = VAL_SERIES   (D_ARG(2));
+
+	Bind_Block(frame, BLK_HEAD(body), BIND_DEEP);
+
+	// Evaluate the body:
+	DO_BLK(D_ARG(2));
+	return R_TOS1;
+}
+
+
 /***********************************************************************
 **
 */	REBNATIVE(not)

src/mezz/mezz-control.reb

@@ -34,14 +34,6 @@ wrap: func [
 	do bind/copy/set body make object! 0
 ]
 
-with: func[
-	"Evaluates a block binded to the specified context."
-	context [object! module!]
-	body    [block!]
-][
-	do bind body context
-]
-
 any-of: func [
 	"Returns the first value(s) for which the test is not FALSE or NONE."
 	'word [word! block!] "Word or block of words to set each time (local)"

src/tests/units/evaluation-test.r3

@@ -211,6 +211,17 @@ Rebol [
 
 ===end-group===
 
+
+===start-group=== "with"
+	--test-- "with"
+		o: object [a: 1]
+		--assert 2 = with o [2 * a]
+		; test that return is not catched by `with`
+		f: does [with o [return a] 2]
+		--assert 1 = f
+===end-group===
+
+
 ===start-group=== "attempt"
 	--test-- "issue-41"
 		--assert none? attempt [2 / 0] ;@@ https://github.com/Oldes/Rebol-issues/issues/41