diff --git a/factor/ExternalFactor.java b/factor/ExternalFactor.java
index 74c5a104d7..eddf657774 100644
--- a/factor/ExternalFactor.java
+++ b/factor/ExternalFactor.java
@@ -254,10 +254,10 @@ public class ExternalFactor extends VocabularyLookup
 		switch(mode)
 		{
 		case COMPLETE_START:
-			predicate = "[ word-name swap string-head? ]";
+			predicate = "[ word-name swap head? ]";
 			break;
 		case COMPLETE_ANYWHERE:
-			predicate = "[ word-name string-contains? ]";
+			predicate = "[ word-name subseq? ]";
 			break;
 		case COMPLETE_EQUAL:
 			predicate = "[ word-name = ]";
diff --git a/library/compiler/optimizer.factor b/library/compiler/optimizer.factor
index 07e10aea4b..3a5c98ce57 100644
--- a/library/compiler/optimizer.factor
+++ b/library/compiler/optimizer.factor
@@ -11,209 +11,207 @@ sequences vectors words words ;
 ! lifted to their call sites. Also, #label nodes are inlined if
 ! their children do not make a recursive call to the label.
 
-! : scan-literal ( node -- )
-!     #! If the node represents a literal push, add the literal to
-!     #! the list being constructed.
-!     "scan-literal" [ drop ] apply-dataflow ;
-! 
-! : (scan-literals) ( dataflow -- )
-!     [ scan-literal ] each ;
-! 
-! : scan-literals ( dataflow -- list )
-!     [ (scan-literals) ] make-list ;
-! 
-! : scan-branches ( branches -- )
-!     #! Collect all literals from all branches.
-!     [ node-param get ] bind [ [ scan-literal ] each ] each ;
-! 
-! : mentions-literal? ( literal list -- ? )
-!     #! Does the given list of result objects refer to this
-!     #! literal?
-!     [ value= ] some-with? ;
-! 
-! : consumes-literal? ( literal node -- ? )
-!     #! Does the dataflow node consume the literal?
-!     [
-!         dup node-consume-d get mentions-literal? swap
-!         dup node-consume-r get mentions-literal? nip or
-!     ] bind ;
-! 
-! : produces-literal? ( literal node -- ? )
-!     #! Does the dataflow node produce the literal?
-!     [
-!         dup node-produce-d get mentions-literal? swap
-!         dup node-produce-r get mentions-literal? nip or
-!     ] bind ;
-! 
-! : (can-kill?) ( literal node -- ? )
-!     #! Return false if the literal appears as input to this
-!     #! node, and this node is not a stack operation.
-!     2dup consumes-literal? >r produces-literal? r> or not ;
-! 
-! : can-kill? ( literal dataflow -- ? )
-!     #! Return false if the literal appears in any node in the
-!     #! list.
-!     [ dupd "can-kill" [ (can-kill?) ] apply-dataflow ] all? nip ;
-! 
-! : kill-set ( dataflow -- list )
-!     #! Push a list of literals that may be killed in the IR.
-!     dup scan-literals [ over can-kill? ] subset nip ;
-! 
-! SYMBOL: branch-returns
-! 
-! : can-kill-branches? ( literal node -- ? )
-!     #! Check if the literal appears in either branch. This
-!     #! assumes that the last element of each branch is a #values
-!     #! node.
-!     2dup consumes-literal? [
-!         2drop f
-!     ] [
-!         [ node-param get ] bind
-!         [
-!             dup [
-!                 peek [ node-consume-d get >vector ] bind
-!             ] map
-!             unify-stacks >list
-!             branch-returns set
-!             [ dupd can-kill? ] all? nip
-!         ] with-scope
-!     ] ifte ;
-! 
-! : kill-node ( literals node -- )
-!     swap [ over (can-kill?) ] all? [ , ] [ drop ] ifte ;
-! 
-! : (kill-nodes) ( literals dataflow -- )
-!     #! Append live nodes to currently constructing list.
-!     [ "kill-node" [ nip , ] apply-dataflow ] each-with ;
-! 
-! : kill-nodes ( literals dataflow -- dataflow )
-!     #! Remove literals and construct a list.
-!     [ (kill-nodes) ] make-list ;
-! 
-! : optimize ( dataflow -- dataflow )
-!     #! Remove redundant literals from the IR. The original IR
-!     #! is destructively modified.
-!     dup kill-set swap kill-nodes ;
-! 
-! : kill-branches ( literals node -- )
-!     [
-!         node-param [ [ dupd kill-nodes ] map nip ] change
-!     ] extend , ;
-! 
-! : kill-literal ( literals values -- values )
-!     [
-!         swap [ swap value= ] some-with? not
-!     ] subset-with ;
-! 
-! #push [
-!     [ node-produce-d get ] bind [ literal-value ] map %
-! ] "scan-literal" set-word-prop
-! 
-! #push [ 2drop t ] "can-kill" set-word-prop
-! 
-! #push [
-!     [ node-produce-d [ kill-literal ] change ] extend ,
-! ] "kill-node" set-word-prop
-! 
-! #drop [ 2drop t ] "can-kill" set-word-prop
-! 
-! #drop [
-!     [ node-consume-d [ kill-literal ] change ] extend ,
-! ] "kill-node" set-word-prop
-! 
-! #label [
-!     [ node-param get ] bind (scan-literals)
-! ] "scan-literal" set-word-prop
-! 
-! #label [
-!     [ node-param get ] bind can-kill?
-! ] "can-kill" set-word-prop
-! 
-! #call-label [
-!     [ node-param get ] bind =
-! ] "calls-label" set-word-prop
-! 
-! : calls-label? ( label list -- ? )
-!     [ "calls-label" [ 2drop f ] apply-dataflow ] some-with? ;
-! 
-! #label [
-!     [ node-param get ] bind calls-label?
-! ] "calls-label" set-word-prop
-! 
-! : branches-call-label? ( label list -- ? )
-!     [ calls-label? ] some-with? ;
-! 
-! \ ifte [
-!     [ node-param get ] bind branches-call-label?
-! ] "calls-label" set-word-prop
-! 
-! \ dispatch [
-!     [ node-param get ] bind branches-call-label?
-! ] "calls-label" set-word-prop
-! 
-! #label [ ( literals node -- )
-!     [ node-param [ kill-nodes ] change ] extend ,
-! ] "kill-node" set-word-prop
-! 
-! #values [
-!     dupd consumes-literal? [
-!         branch-returns get mentions-literal?
-!     ] [
-!         drop t
-!     ] ifte
-! ] "can-kill" set-word-prop
-! 
-! \ ifte [ scan-branches ] "scan-literal" set-word-prop
-! \ ifte [ can-kill-branches? ] "can-kill" set-word-prop
-! \ ifte [ kill-branches ] "kill-node" set-word-prop
-! 
-! \ dispatch [ scan-branches ] "scan-literal" set-word-prop
-! \ dispatch [ can-kill-branches? ] "can-kill" set-word-prop
-! \ dispatch [ kill-branches ] "kill-node" set-word-prop
-! 
-! ! Don't care about inputs to recursive combinator calls
-! #call-label [ 2drop t ] "can-kill" set-word-prop
-! 
-! \ drop [ 2drop t ] "can-kill" set-word-prop
-! \ drop [ kill-node ] "kill-node" set-word-prop
-! \ dup [ 2drop t ] "can-kill" set-word-prop
-! \ dup [ kill-node ] "kill-node" set-word-prop
-! \ swap [ 2drop t ] "can-kill" set-word-prop
-! \ swap [ kill-node ] "kill-node" set-word-prop
-! 
-! : kill-mask ( killing inputs -- mask )
-!     [ over [ over value= ] some? >boolean nip ] map nip ;
-! 
-! : reduce-stack-op ( literals node map -- )
-!     #! If certain values passing through a stack op are being
-!     #! killed, the stack op can be reduced, in extreme cases
-!     #! to a no-op.
-!     -rot [
-!         [ node-consume-d get ] bind kill-mask swap assoc
-!     ] keep
-!     over [ [ node-op set ] extend , ] [ 2drop ] ifte ;
-! 
-! \ over [ 2drop t ] "can-kill" set-word-prop
-! \ over [
-!     [
-!         [[ [ f f ] over ]]
-!         [[ [ f t ] dup  ]]
-!     ] reduce-stack-op
-! ] "kill-node" set-word-prop
-! 
-! \ pick [ 2drop t ] "can-kill" set-word-prop
-! \ pick [
-!     [
-!         [[ [ f f f ] pick ]]
-!         [[ [ f f t ] over ]]
-!         [[ [ f t f ] over ]]
-!         [[ [ f t t ] dup  ]]
-!     ] reduce-stack-op
-! ] "kill-node" set-word-prop
-! 
-! \ >r [ 2drop t ] "can-kill" set-word-prop
-! \ >r [ kill-node ] "kill-node" set-word-prop
-! \ r> [ 2drop t ] "can-kill" set-word-prop
-! \ r> [ kill-node ] "kill-node" set-word-prop
+: scan-literal ( node -- )
+    #! If the node represents a literal push, add the literal to
+    #! the list being constructed.
+    "scan-literal" [ drop ] apply-dataflow ;
 
-: optimize ;
+: (scan-literals) ( dataflow -- )
+    [ scan-literal ] each ;
+
+: scan-literals ( dataflow -- list )
+    [ (scan-literals) ] make-list ;
+
+: scan-branches ( branches -- )
+    #! Collect all literals from all branches.
+    [ node-param get ] bind [ [ scan-literal ] each ] each ;
+
+: mentions-literal? ( literal list -- ? )
+    #! Does the given list of result objects refer to this
+    #! literal?
+    [ value= ] some-with? ;
+
+: consumes-literal? ( literal node -- ? )
+    #! Does the dataflow node consume the literal?
+    [
+        dup node-consume-d get mentions-literal? swap
+        dup node-consume-r get mentions-literal? nip or
+    ] bind ;
+
+: produces-literal? ( literal node -- ? )
+    #! Does the dataflow node produce the literal?
+    [
+        dup node-produce-d get mentions-literal? swap
+        dup node-produce-r get mentions-literal? nip or
+    ] bind ;
+
+: (can-kill?) ( literal node -- ? )
+    #! Return false if the literal appears as input to this
+    #! node, and this node is not a stack operation.
+    2dup consumes-literal? >r produces-literal? r> or not ;
+
+: can-kill? ( literal dataflow -- ? )
+    #! Return false if the literal appears in any node in the
+    #! list.
+    [ dupd "can-kill" [ (can-kill?) ] apply-dataflow ] all? nip ;
+
+: kill-set ( dataflow -- list )
+    #! Push a list of literals that may be killed in the IR.
+    dup scan-literals [ over can-kill? ] subset nip ;
+
+SYMBOL: branch-returns
+
+: can-kill-branches? ( literal node -- ? )
+    #! Check if the literal appears in either branch. This
+    #! assumes that the last element of each branch is a #values
+    #! node.
+    2dup consumes-literal? [
+        2drop f
+    ] [
+        [ node-param get ] bind
+        [
+            dup [
+                peek [ node-consume-d get >vector ] bind
+            ] map
+            unify-stacks >list
+            branch-returns set
+            [ dupd can-kill? ] all? nip
+        ] with-scope
+    ] ifte ;
+
+: kill-node ( literals node -- )
+    swap [ over (can-kill?) ] all? [ , ] [ drop ] ifte ;
+
+: (kill-nodes) ( literals dataflow -- )
+    #! Append live nodes to currently constructing list.
+    [ "kill-node" [ nip , ] apply-dataflow ] each-with ;
+
+: kill-nodes ( literals dataflow -- dataflow )
+    #! Remove literals and construct a list.
+    [ (kill-nodes) ] make-list ;
+
+: optimize ( dataflow -- dataflow )
+    #! Remove redundant literals from the IR. The original IR
+    #! is destructively modified.
+    dup kill-set swap kill-nodes ;
+
+: kill-branches ( literals node -- )
+    [
+        node-param [ [ dupd kill-nodes ] map nip ] change
+    ] extend , ;
+
+: kill-literal ( literals values -- values )
+    [
+        swap [ swap value= ] some-with? not
+    ] subset-with ;
+
+#push [
+    [ node-produce-d get ] bind [ literal-value ] map %
+] "scan-literal" set-word-prop
+
+#push [ 2drop t ] "can-kill" set-word-prop
+
+#push [
+    [ node-produce-d [ kill-literal ] change ] extend ,
+] "kill-node" set-word-prop
+
+#drop [ 2drop t ] "can-kill" set-word-prop
+
+#drop [
+    [ node-consume-d [ kill-literal ] change ] extend ,
+] "kill-node" set-word-prop
+
+#label [
+    [ node-param get ] bind (scan-literals)
+] "scan-literal" set-word-prop
+
+#label [
+    [ node-param get ] bind can-kill?
+] "can-kill" set-word-prop
+
+#call-label [
+    [ node-param get ] bind =
+] "calls-label" set-word-prop
+
+: calls-label? ( label list -- ? )
+    [ "calls-label" [ 2drop f ] apply-dataflow ] some-with? ;
+
+#label [
+    [ node-param get ] bind calls-label?
+] "calls-label" set-word-prop
+
+: branches-call-label? ( label list -- ? )
+    [ calls-label? ] some-with? ;
+
+\ ifte [
+    [ node-param get ] bind branches-call-label?
+] "calls-label" set-word-prop
+
+\ dispatch [
+    [ node-param get ] bind branches-call-label?
+] "calls-label" set-word-prop
+
+#label [ ( literals node -- )
+    [ node-param [ kill-nodes ] change ] extend ,
+] "kill-node" set-word-prop
+
+#values [
+    dupd consumes-literal? [
+        branch-returns get mentions-literal?
+    ] [
+        drop t
+    ] ifte
+] "can-kill" set-word-prop
+
+\ ifte [ scan-branches ] "scan-literal" set-word-prop
+\ ifte [ can-kill-branches? ] "can-kill" set-word-prop
+\ ifte [ kill-branches ] "kill-node" set-word-prop
+
+\ dispatch [ scan-branches ] "scan-literal" set-word-prop
+\ dispatch [ can-kill-branches? ] "can-kill" set-word-prop
+\ dispatch [ kill-branches ] "kill-node" set-word-prop
+
+! Don't care about inputs to recursive combinator calls
+#call-label [ 2drop t ] "can-kill" set-word-prop
+
+\ drop [ 2drop t ] "can-kill" set-word-prop
+\ drop [ kill-node ] "kill-node" set-word-prop
+\ dup [ 2drop t ] "can-kill" set-word-prop
+\ dup [ kill-node ] "kill-node" set-word-prop
+\ swap [ 2drop t ] "can-kill" set-word-prop
+\ swap [ kill-node ] "kill-node" set-word-prop
+
+: kill-mask ( killing inputs -- mask )
+    [ over [ over value= ] some? >boolean nip ] map nip ;
+
+: reduce-stack-op ( literals node map -- )
+    #! If certain values passing through a stack op are being
+    #! killed, the stack op can be reduced, in extreme cases
+    #! to a no-op.
+    -rot [
+        [ node-consume-d get ] bind kill-mask swap assoc
+    ] keep
+    over [ [ node-op set ] extend , ] [ 2drop ] ifte ;
+
+\ over [ 2drop t ] "can-kill" set-word-prop
+\ over [
+    [
+        [[ [ f f ] over ]]
+        [[ [ f t ] dup  ]]
+    ] reduce-stack-op
+] "kill-node" set-word-prop
+
+\ pick [ 2drop t ] "can-kill" set-word-prop
+\ pick [
+    [
+        [[ [ f f f ] pick ]]
+        [[ [ f f t ] over ]]
+        [[ [ f t f ] over ]]
+        [[ [ f t t ] dup  ]]
+    ] reduce-stack-op
+] "kill-node" set-word-prop
+
+\ >r [ 2drop t ] "can-kill" set-word-prop
+\ >r [ kill-node ] "kill-node" set-word-prop
+\ r> [ 2drop t ] "can-kill" set-word-prop
+\ r> [ kill-node ] "kill-node" set-word-prop