diff --git a/extra/modern/modern.factor b/extra/modern/modern.factor
index 6d1c752273..24697e2367 100644
--- a/extra/modern/modern.factor
+++ b/extra/modern/modern.factor
@@ -59,7 +59,7 @@ MACRO:: read-double-matched ( open-ch -- quot: ( string n tag ch -- string n' se
         ch {
             { char: = [
                 tag 1 cut-slice* drop tag! ! tag of (=( is ( here, fix it
-                string n openstr1 slice-til-separator-inclusive [ -1 modify-from ] dip :> ( string' n' opening ch )
+                string n openstr1 slice-until-include [ -1 modify-from ] dip :> ( string' n' opening ch )
                 ch open-ch = [ tag openstr2 string n ch long-opening-mismatch ] unless
                 opening matching-delimiter-string :> needle
 
@@ -133,7 +133,7 @@ MACRO:: read-matched ( ch -- quot: ( string n tag -- string n' slice' ) )
     ch dup matching-delimiter {
         [ drop "=" swap prefix ]
         [ nip 1string ]
-    } 2cleave :> ( openstreq closestr1 )  ! [= ]
+    } 2cleave :> ( openstreq closestr1 ) ! [= ]
     |[ string n tag |
         string n tag
         2over nth-check-eof {
@@ -142,7 +142,7 @@ MACRO:: read-matched ( ch -- quot: ( string n tag -- string n' slice' ) )
                 drop dup '[ _ matching-delimiter-string closestr1 2array members lex-until ] dip
                 swap unclip-last 3array
             ] } ! ( foo )
-            [ drop [ slice-til-whitespace drop ] dip span-slices ]  ! (foo)
+            [ drop [ slice-til-whitespace drop ] dip span-slices ] ! (foo)
         } cond
     ] ;
 
@@ -151,7 +151,7 @@ MACRO:: read-matched ( ch -- quot: ( string n tag -- string n' slice' ) )
 : read-paren ( string n slice -- string n' slice' ) char: \( read-matched ;
 : read-string-payload ( string n -- string n' )
     dup [
-        { char: \\ char: \" } slice-til-separator-inclusive {
+        { char: \\ char: \" } slice-until-include {
             { f [ drop ] }
             { char: \" [ drop ] }
             { char: \\ [ drop next-char-from drop read-string-payload ] }
@@ -423,7 +423,7 @@ DEFER: lex-factor-top*
         { char: \" [ read-string ] }
         { char: \! [ read-exclamation ] }
         { char: > [
-            [ [ char: > = not ] slice-until ] dip merge-slices
+            [ [ char: > = not ] slice-until-exclude drop ] dip merge-slices
             dup section-close? [
                 [ slice-til-whitespace drop ] dip ?span-slices
             ] unless
diff --git a/extra/modern/slices/slices.factor b/extra/modern/slices/slices.factor
index 4cad3dc16f..c87916ba78 100644
--- a/extra/modern/slices/slices.factor
+++ b/extra/modern/slices/slices.factor
@@ -24,17 +24,22 @@ IN: modern.slices
         rest ">" append
     ] if ;
 
+: slice-between ( slice1 slice2 -- slice )
+    ! ensure-same-underlying
+    slice-order-by-from
+    [ to>> ]
+    [ [ from>> 2dup < [ swap ] unless ] [ seq>> ] bi ] bi* <slice> ;
+
+: slice-before ( slice -- slice' )
+    [ drop 0 ] [ from>> ] [ seq>> ] tri <slice> ;
+
 ERROR: unexpected-end string n ;
 : nth-check-eof ( string n -- nth )
     2dup ?nth-of [ 2nip ] [ unexpected-end ] if* ;
 
 ! Allow eof
 : next-char-from ( string n/f -- string n'/f ch/f )
-    dup [
-        2dup ?nth-of dup [ [ 1 + ] dip ] when
-    ] [
-        f
-    ] if ;
+    dup [ 2dup ?nth-of dup [ [ 1 + ] dip ] when ] [ f ] if ;
 
 : find-from' ( ... seq n quot: ( ... elt -- ... ? ) -- ... i elt )
     swapd find-from ; inline
@@ -46,72 +51,46 @@ ERROR: unexpected-end string n ;
 : find-from*' ( ... seq n quot: ( ... elt -- ... ? ) -- ... i elt ? )
     swapd find-from* ; inline
 
-:: (slice-until) ( string n quot -- string n' slice/f ch/f )
-    string n quot find-from' :> ( n' ch )
-    string n'
-    n n' string ?<slice>
-    ch ; inline
+: slice-until-exclude ( string n quot -- string n' slice/f ch/f )
+    [ drop ]
+    [ find-from' ] 3bi ! ( string n n' ch )
+    [ drop nip ]
+    [ [ rot ?<slice> ] dip ] 4bi ; inline
 
-: slice-until ( string n quot -- string n' slice/f )
-    (slice-until) drop ; inline
-
-! Don't include the whitespace in the slice
-:: slice-til-quot ( string n quot -- string n'/f slice/f ch/f )
-    n [
-        ! BUG: (slice-until) is broken here?!
-        string n quot find-from' :> ( n' ch )
-        string n'
-        n n' string ?<slice>
-        ch
-    ] [
-        string f f f
-    ] if ; inline
+: slice-until-include ( string n tokens -- string n' slice/f ch/f )
+    '[ _ member? ]
+    [ drop ]
+    [ find-from' [ ?1+ ] dip ] 3bi ! ( string n n' ch )
+    [ drop nip ]
+    [ [ rot ?<slice> ] dip ] 4bi ; inline
 
 : slice-til-whitespace ( string n -- string n' slice/f ch/f )
-    [ "\s\r\n" member? ] slice-til-quot ; inline
+    [ "\s\r\n" member? ] slice-until-exclude ; inline
 
 : slice-til-not-whitespace ( string n -- string n' slice/f ch/f )
-    [ "\s\r\n" member? not ] slice-til-quot ; inline
+    [ "\s\r\n" member? not ] slice-until-exclude ; inline
 
 : skip-whitespace ( string n/f -- string n'/f )
     slice-til-not-whitespace 2drop ;
 
-: empty-slice-end ( seq -- slice )
-    [ length dup ] [ ] bi <slice> ; inline
+: slice-til-eol ( string n -- string n' slice/f ch/f )
+    [ "\r\n" member? ] slice-until-exclude ; inline
 
-:: slice-til-eol ( string n -- string n' slice/f ch/f )
-    n [
-        string n '[ "\r\n" member? ] find-from' :> ( n' ch )
-        string n'
-        n n' string ?<slice>
-        ch
-    ] [
-        string n
-        string empty-slice-end
-        f
-    ] if ; inline
-
-: merge-slice-til-whitespace ( string n slice --  string n' slice' )
+: merge-slice-til-whitespace ( string n slice -- string n' slice' )
     over [
         [ slice-til-whitespace drop ] dip merge-slices
     ] when ;
 
-: merge-slice-til-not-whitespace ( string n slice --  string n' slice' )
+: merge-slice-til-not-whitespace ( string n slice -- string n' slice' )
     over [
         [ slice-til-not-whitespace drop ] dip merge-slices
     ] when ;
 
-:: slice-til-separator-inclusive ( string n tokens -- string n' slice/f ch/f )
-    string n '[ tokens member? ] find-from' [ ?1+ ] dip  :> ( n' ch )
-    string
-    n'
-    n n' string ?<slice>
-    ch ; inline
 
 ! Takes at least one character if not whitespace
 :: slice-til-either ( string n tokens -- string n'/f slice/f ch/f )
     n [
-        string n '[ tokens member? ] find-from'
+        string n [ tokens member? ] find-from'
         dup "\s\r\n" member? [ [ ?1+ ] dip ] unless :> ( n' ch )
         string
         n'
@@ -123,7 +102,7 @@ ERROR: unexpected-end string n ;
 
 ERROR: subseq-expected-but-got-eof string n expected ;
 
-:: slice-til-string ( string n search --  string n'/f payload end-string )
+:: slice-til-string ( string n search -- string n'/f payload end-string )
     search string n subseq-start-from :> n'
     n' [ string n search subseq-expected-but-got-eof ] unless
     string