diff --git a/moo/kernel/Collect.moo b/moo/kernel/Collect.moo
index 7585ae1..b81bfab 100644
--- a/moo/kernel/Collect.moo
+++ b/moo/kernel/Collect.moo
@@ -28,8 +28,7 @@ class Collection(Object)
 
 	method detect: block
 	{
-		self do: [ :el | if (block value: el) { ^el } ].
-		^Error.Code.ENOENT
+		self detect: block ifNone: [ ^self error: 'not found' ].
 	}
 
 	method detect: block ifNone: exception_block
@@ -43,7 +42,16 @@ class Collection(Object)
 	{
 		self subclassResponsibility: #add:.
 	}
-	
+*)
+
+	method collect: block
+	{
+		| coll |
+		coll := self class new: self basicSize.
+		self do: [ :el | coll add: (block value: el) ].
+		^coll
+	}
+
 	method select: condition_block
 	{
 		| coll |
@@ -56,11 +64,9 @@ class Collection(Object)
 	{
 		| coll |
 		coll := self class new: self basicSize.
-		self do: [ :el | if (condition_block value: el) { } else { coll add: el } ].
+		self do: [ :el | ifnot (condition_block value: el) { coll add: el } ].
 		^coll
 	}
-*)
-
 
 	method emptyCheck
 	{
diff --git a/moo/kernel/Fcgi.moo b/moo/kernel/Fcgi.moo
index ed134e5..ca4e319 100644
--- a/moo/kernel/Fcgi.moo
+++ b/moo/kernel/Fcgi.moo
@@ -219,6 +219,8 @@ class Fcgi.ParamRecord(Fcgi.Record)
 
 		if (aString notNil)
 		{
+### TODO: implement this...
+(*
 			(aString subStrings: %(char)) do: [:each | 
 				equal := each indexOf: $=.
 				equal = 0 
@@ -226,8 +228,8 @@ class Fcgi.ParamRecord(Fcgi.Record)
 					ifFalse: [
 					tempFields 
 						at: (each first: equal - 1) 
-						put: (each allButFirst: equal)]
-			]
+						put: (each allButFirst: equal)] 
+			] *)
 		}.
 
 		^tempFields
diff --git a/moo/kernel/System.moo b/moo/kernel/System.moo
index c863fee..c31f505 100644
--- a/moo/kernel/System.moo
+++ b/moo/kernel/System.moo
@@ -33,10 +33,10 @@ class System(Apex)
 
 		self.asyncsg := SemaphoreGroup new.
 
-		class := System at: class_name.
+		class := self at: class_name. ## System at: class_name.
 		if (class isError)
 		{
-			System error: ('Cannot find the class - ' & class_name).
+			self error: ('Cannot find the class - ' & class_name).
 		}.
 
 		## start the gc finalizer process
diff --git a/moo/lib/comp.c b/moo/lib/comp.c
index c77c2a8..0cf86d4 100644
--- a/moo/lib/comp.c
+++ b/moo/lib/comp.c
@@ -117,6 +117,7 @@ static struct voca_t
 	{  5, { '#','d','u','a','l'                                           } },
 	{  4, { 'e','l','s','e'                                               } },
 	{  5, { 'e','l','s','i','f'                                           } },
+	{  8, { 'e','l','s','i','f','n','o','t'                               } },
 	{  6, { 'e','n','s','u','r','e',                                      } },
 	{  9, { 'e','x','c','e','p','t','i','o','n'                           } },
 	{  6, { 'e','x','t','e','n','d'                                       } },
@@ -126,6 +127,7 @@ static struct voca_t
 	{  4, { '#','g','e','t'                                               } },
 	{  9, { '#','h','a','l','f','w','o','r','d'                           } },
 	{  2, { 'i','f'                                                       } },
+	{  5, { 'i','f','n','o','t'                                           } },
 	{ 10, { '#','i','m','m','u','t','a','b','l','e'                       } },
 	{  6, { 'i','m','p','o','r','t'                                       } },
 	{  8, { '#','i','n','c','l','u','d','e'                               } },
@@ -183,6 +185,7 @@ enum voca_id_t
 	VOCA_DUAL_S,
 	VOCA_ELSE,
 	VOCA_ELSIF,
+	VOCA_ELSIFNOT,
 	VOCA_ENSURE,
 	VOCA_EXCEPTION,
 	VOCA_EXTEND,
@@ -192,6 +195,7 @@ enum voca_id_t
 	VOCA_GET_S,
 	VOCA_HALFWORD_S,
 	VOCA_IF,
+	VOCA_IFNOT,
 	VOCA_IMMUTABLE_S,
 	VOCA_IMPORT,
 	VOCA_INCLUDE_S,
@@ -372,6 +376,7 @@ static int is_reserved_word (const moo_oocs_t* ucs)
 		VOCA_IF,
 		VOCA_ELSE,
 		VOCA_ELSIF,
+		VOCA_ELSIFNOT,
 		VOCA_WHILE,
 		VOCA_UNTIL,
 		VOCA_DO,
@@ -1204,6 +1209,10 @@ static int get_ident (moo_t* moo, moo_ooci_t char_read_ahead)
 		{
 			SET_TOKEN_TYPE (moo, MOO_IOTOK_IF);
 		}
+		else if (is_token_word(moo, VOCA_IFNOT))
+		{
+			SET_TOKEN_TYPE (moo, MOO_IOTOK_IFNOT);
+		}
 		else if (is_token_word(moo, VOCA_ELSE))
 		{
 			SET_TOKEN_TYPE (moo, MOO_IOTOK_ELSE);
@@ -1212,6 +1221,10 @@ static int get_ident (moo_t* moo, moo_ooci_t char_read_ahead)
 		{
 			SET_TOKEN_TYPE (moo, MOO_IOTOK_ELSIF);
 		}
+		else if (is_token_word(moo, VOCA_ELSIFNOT))
+		{
+			SET_TOKEN_TYPE (moo, MOO_IOTOK_ELSIFNOT);
+		}
 		else if (is_token_word(moo, VOCA_WHILE))
 		{
 			SET_TOKEN_TYPE (moo, MOO_IOTOK_WHILE);
@@ -5661,14 +5674,28 @@ static int compile_if_expression (moo_t* moo)
 	moo_oow_t i, j;
 	moo_oow_t jumptonext, precondpos, postcondpos, endoftrueblock;
 	moo_ioloc_t if_loc, brace_loc;
+	int jumpop_inst, push_true_inst, push_false_inst;
 
-	MOO_ASSERT (moo, TOKEN_TYPE(moo) == MOO_IOTOK_IF);
+	MOO_ASSERT (moo, TOKEN_TYPE(moo) == MOO_IOTOK_IF || TOKEN_TYPE(moo) == MOO_IOTOK_IFNOT);
 	if_loc = *TOKEN_LOC(moo);
 
 	init_oow_pool (moo, &jumptoend);
 	jumptonext = INVALID_IP;
 	endoftrueblock = INVALID_IP;
 
+	if (TOKEN_TYPE(moo) == MOO_IOTOK_IF)
+	{
+		push_true_inst = BCODE_PUSH_TRUE;
+		push_false_inst = BCODE_PUSH_FALSE;
+		jumpop_inst = BCODE_JUMPOP_FORWARD_IF_FALSE;
+	}
+	else
+	{
+		push_true_inst = BCODE_PUSH_FALSE;
+		push_false_inst = BCODE_PUSH_TRUE;
+		jumpop_inst = BCODE_JUMPOP_FORWARD_IF_TRUE;
+	}
+
 	do
 	{
 		int falseblock = 0;
@@ -5677,12 +5704,12 @@ static int compile_if_expression (moo_t* moo)
 		precondpos = moo->c->mth.code.len;
 
 		if (jumptonext != INVALID_IP &&
-		    patch_long_forward_jump_instruction (moo, jumptonext, precondpos, &brace_loc) <= -1) goto oops;
+		    patch_long_forward_jump_instruction(moo, jumptonext, precondpos, &brace_loc) <= -1) goto oops;
 
 		if (compile_conditional(moo) <= -1) goto oops;
 		postcondpos = moo->c->mth.code.len;
 
-		if (precondpos + 1 == postcondpos && moo->c->mth.code.ptr[precondpos] == BCODE_PUSH_TRUE)
+		if (precondpos + 1 == postcondpos && moo->c->mth.code.ptr[precondpos] == push_true_inst)
 		{
 			/* do not generate jump */
 			jumptonext = INVALID_IP;
@@ -5692,7 +5719,7 @@ static int compile_if_expression (moo_t* moo)
 			eliminate_instructions (moo, precondpos, moo->c->mth.code.len - 1);
 			postcondpos = precondpos;
 		}
-		else if (precondpos + 1 == postcondpos && moo->c->mth.code.ptr[precondpos] == BCODE_PUSH_FALSE)
+		else if (precondpos + 1 == postcondpos && moo->c->mth.code.ptr[precondpos] == push_false_inst)
 		{
 			jumptonext = INVALID_IP;
 			/* mark that the conditional is false. instructions will get eliminated below */
@@ -5704,7 +5731,7 @@ static int compile_if_expression (moo_t* moo)
 			jumptonext = moo->c->mth.code.len; 
 			/* BCODE_JUMPOP_FORWARD_IF_FALSE is always a long jump instruction.
 			 * just specify MAX_CODE_JUMP for consistency with short jump variants */
-			if (emit_single_param_instruction (moo, BCODE_JUMPOP_FORWARD_IF_FALSE, MAX_CODE_JUMP) <= -1) goto oops;
+			if (emit_single_param_instruction(moo, jumpop_inst, MAX_CODE_JUMP) <= -1) goto oops;
 		}
 
 		GET_TOKEN (moo); /* get { */
@@ -5737,10 +5764,26 @@ static int compile_if_expression (moo_t* moo)
 		}
 
 		GET_TOKEN (moo); /* get the next token after } */
-	} while (TOKEN_TYPE(moo) == MOO_IOTOK_ELSIF);
+
+		if (TOKEN_TYPE(moo) !=  MOO_IOTOK_ELSIF && TOKEN_TYPE(moo) != MOO_IOTOK_ELSIFNOT) break;
+
+		if (TOKEN_TYPE(moo) == MOO_IOTOK_ELSIF)
+		{
+			push_true_inst = BCODE_PUSH_TRUE;
+			push_false_inst = BCODE_PUSH_FALSE;
+			jumpop_inst = BCODE_JUMPOP_FORWARD_IF_FALSE;
+		}
+		else
+		{
+			push_true_inst = BCODE_PUSH_FALSE;
+			push_false_inst = BCODE_PUSH_TRUE;
+			jumpop_inst = BCODE_JUMPOP_FORWARD_IF_TRUE;
+		}
+	}
+	while (1);
 
 	if (jumptonext != INVALID_IP &&
-	    patch_long_forward_jump_instruction (moo, jumptonext, moo->c->mth.code.len, &brace_loc) <= -1) goto oops;
+	    patch_long_forward_jump_instruction(moo, jumptonext, moo->c->mth.code.len, &brace_loc) <= -1) goto oops;
 
 	if (TOKEN_TYPE(moo) == MOO_IOTOK_ELSE)
 	{
@@ -6033,7 +6076,7 @@ static int compile_method_expression (moo_t* moo, int pop)
 	MOO_ASSERT (moo, pop == 0 || pop == 1);
 	MOO_MEMSET (&assignee, 0, MOO_SIZEOF(assignee));
 
-	if (TOKEN_TYPE(moo) == MOO_IOTOK_IF)
+	if (TOKEN_TYPE(moo) == MOO_IOTOK_IF || TOKEN_TYPE(moo) == MOO_IOTOK_IFNOT)
 	{
 		if (compile_if_expression (moo) <= -1) return -1;
 	}
diff --git a/moo/lib/moo-prv.h b/moo/lib/moo-prv.h
index 6e3b66b..cac3e50 100644
--- a/moo/lib/moo-prv.h
+++ b/moo/lib/moo-prv.h
@@ -342,8 +342,10 @@ enum moo_iotok_type_t
 	MOO_IOTOK_SELFNS,
 
 	MOO_IOTOK_IF,
+	MOO_IOTOK_IFNOT,
 	MOO_IOTOK_ELSE,
 	MOO_IOTOK_ELSIF,
+	MOO_IOTOK_ELSIFNOT,
 
 	MOO_IOTOK_WHILE,
 	MOO_IOTOK_UNTIL,
@@ -852,6 +854,7 @@ enum moo_bcode_t
 	BCODE_JUMP_BACKWARD_2          = 0x4A, /* 74 */
 	BCODE_JUMP_BACKWARD_3          = 0x4B, /* 75 */
 
+	/* JUMPOP = JUMP + POP */
 	BCODE_JUMPOP_BACKWARD_IF_FALSE_0 = 0x4C, /* 76 */
 	BCODE_JUMPOP_BACKWARD_IF_FALSE_1 = 0x4D, /* 77 */
 	BCODE_JUMPOP_BACKWARD_IF_FALSE_2 = 0x4E, /* 78 */