- Moved the lux/data/struct/* modules to lux/data/coll/*.

- Did the same for the lux/codata/struct/* modules.
- Moved lux/codata/io to lux/io.
- Moved lux/control/effect to lux/effect.
- Renamed "sample" functions to "this" functions.
- Renamed "at" functions to "nth" functions.

46 files changed, 181 insertions, 175 deletions

diff --git a/stdlib/source/lux.lux b/stdlib/source/lux.lux
index bb53b987e..f86d8cdae 100644
--- a/stdlib/source/lux.lux
+++ b/stdlib/source/lux.lux
@@ -3234,7 +3234,7 @@
       (list module)
       (list& (substring2 0 idx module) (split-module (substring1 (i.+ 1 idx) module))))))
 
-(def: (at idx xs)
+(def: (nth idx xs)
   (All [a]
     (-> Int (List a) (Maybe a)))
   (case xs
@@ -3244,7 +3244,7 @@
     (#Cons x xs')
     (if (i.= idx 0)
       (#Some x)
-      (at (i.- 1 idx) xs')
+      (nth (i.- 1 idx) xs')
       )))
 
 (def: (beta-reduce env type)
@@ -3279,7 +3279,7 @@
     (#LambdaT (beta-reduce env ?input) (beta-reduce env ?output))
 
     (#BoundT idx)
-    (case (at (_lux_proc ["nat" "to-int"] [idx]) env)
+    (case (nth (_lux_proc ["nat" "to-int"] [idx]) env)
       (#Some bound)
       bound
 
@@ -3870,7 +3870,7 @@
             num-ups (length ups)]
         (if (i.= num-ups 0)
           (return module)
-          (case (at num-ups (split-module-contexts module-name))
+          (case (nth num-ups (split-module-contexts module-name))
             #None
             (fail (Text/append "Can't clean module: " module))
 
@@ -4491,7 +4491,7 @@
             lux
             (lux (control (monad #as M #refer #all))
                  (data (text #open (\"Text/\" Monoid<Text>))
-                       (struct (list #open (\"List/\" Monad<List>)))
+                       (coll (list #open (\"List/\" Monad<List>)))
                        maybe
                        (ident #open (\"Ident/\" Codec<Text,Ident>)))
                  meta
@@ -4502,7 +4502,7 @@
             lux
             (lux (control [\"M\" monad #*])
                  (data [text \"Text/\" Monoid<Text>]
-                       (struct [list \"List/\" Monad<List>])
+                       (coll [list \"List/\" Monad<List>])
                        maybe
                        [ident \"Ident/\" Codec<Text,Ident>])
                  meta
@@ -4735,7 +4735,7 @@
                [#;ExQ])
 
               (#;BoundT idx)
-              (default type (list;at idx env))
+              (default type (list;nth idx env))
 
               _
               type
diff --git a/stdlib/source/lux/cli.lux b/stdlib/source/lux/cli.lux
index a8604180b..410cd42d5 100644
--- a/stdlib/source/lux/cli.lux
+++ b/stdlib/source/lux/cli.lux
@@ -8,11 +8,11 @@
   (lux (control functor
                 applicative
                 monad)
-       (data (struct (list #as list #open ("List/" Monoid<List> Monad<List>)))
+       (data (coll (list #as list #open ("List/" Monoid<List> Monad<List>)))
              (text #as text #open ("Text/" Monoid<Text>))
              error
              (sum #as sum))
-       (codata [io])
+       [io]
        [compiler #+ with-gensyms Functor<Lux> Monad<Lux>]
        (macro [ast]
               ["s" syntax #+ syntax: Syntax])))
diff --git a/stdlib/source/lux/codata/struct/stream.lux b/stdlib/source/lux/codata/coll/stream.lux
index 5691b0c69..eeee1ccc2 100644
--- a/stdlib/source/lux/codata/struct/stream.lux
+++ b/stdlib/source/lux/codata/coll/stream.lux
@@ -10,7 +10,7 @@
                 comonad)
        [compiler #+ with-gensyms]
        (macro ["s" syntax #+ syntax: Syntax])
-       (data (struct [list "List/" Monad<List>])
+       (data (coll [list "List/" Monad<List>])
              bool)
        (codata [cont #+ @lazy Cont])))
 
@@ -59,11 +59,11 @@
   [head a          h]
   [tail (Stream a) t])
 
-(def: #export (at idx s)
+(def: #export (nth idx s)
   (All [a] (-> Nat (Stream a) a))
   (let [[h t] (cont;run s)]
     (if (n.> +0 idx)
-      (at (n.dec idx) t)
+      (nth (n.dec idx) t)
       h)))
 
 (do-template [<taker> <dropper> <splitter> <pred-type> <pred-test> <pred-step>]
diff --git a/stdlib/source/lux/codata/cont.lux b/stdlib/source/lux/codata/cont.lux
index 7f1b787e1..f04b6a0ba 100644
--- a/stdlib/source/lux/codata/cont.lux
+++ b/stdlib/source/lux/codata/cont.lux
@@ -9,7 +9,7 @@
        (control functor
                 applicative
                 monad)
-       (data (struct list)))
+       (data (coll list)))
   (.. function))
 
 ## [Types]
@@ -42,11 +42,17 @@
          (k a))
        k)))
 
+(def: #export (continue f thunk)
+  {#;doc "Forces a continuation thunk to be evaluated."}
+  (All [i o]
+    (-> (-> i o) (Cont i o) o))
+  (thunk f))
+
 (def: #export (run thunk)
   {#;doc "Forces a continuation thunk to be evaluated."}
   (All [a]
     (-> (Cont a) a))
-  (thunk id))
+  (continue id thunk))
 
 ## [Structs]
 (struct: #export _ (Functor Cont)
diff --git a/stdlib/source/lux/compiler.lux b/stdlib/source/lux/compiler.lux
index 367217524..9f667ebce 100644
--- a/stdlib/source/lux/compiler.lux
+++ b/stdlib/source/lux/compiler.lux
@@ -9,7 +9,7 @@
        (control functor
                 applicative
                 monad)
-       (data (struct [list #* "List/" Monoid<List> Monad<List>])
+       (data (coll [list #* "List/" Monoid<List> Monad<List>])
              [number]
              [text "Text/" Monoid<Text> Eq<Text>]
              [product]
diff --git a/stdlib/source/lux/concurrency/actor.lux b/stdlib/source/lux/concurrency/actor.lux
index e55386d9d..73529e987 100644
--- a/stdlib/source/lux/concurrency/actor.lux
+++ b/stdlib/source/lux/concurrency/actor.lux
@@ -6,11 +6,11 @@
 (;module: {#;doc "The actor model of concurrency."}
   lux
   (lux (control monad)
-       (codata [io #- run]
-               function)
+       [io #- run]
+       (codata function)
        (data [error #- fail]
              text/format
-             (struct [list "List/" Monoid<List> Monad<List>])
+             (coll [list "List/" Monoid<List> Monad<List>])
              [product]
              [number "Nat/" Codec<Text,Nat>])
        [compiler #+ with-gensyms]
@@ -154,7 +154,7 @@
 (def: method^
   (Syntax Method)
   (s;form (do s;Monad<Syntax>
-            [_ (s;sample! (' method:))
+            [_ (s;this! (' method:))
              vars (s;default (list) (s;tuple (s;some s;local-symbol)))
              [name args] (s;form ($_ s;seq
                                      s;local-symbol
@@ -171,7 +171,7 @@
 (def: stop^
   (Syntax AST)
   (s;form (do s;Monad<Syntax>
-            [_ (s;sample! (' stop:))]
+            [_ (s;this! (' stop:))]
             s;any)))
 
 (def: actor-decl^
diff --git a/stdlib/source/lux/concurrency/atom.lux b/stdlib/source/lux/concurrency/atom.lux
index ae8c7fa21..c879db02d 100644
--- a/stdlib/source/lux/concurrency/atom.lux
+++ b/stdlib/source/lux/concurrency/atom.lux
@@ -5,7 +5,7 @@
 
 (;module:
   lux
-  (lux (codata [io #- run])
+  (lux [io #- run]
        host))
 
 (jvm-import (java.util.concurrent.atomic.AtomicReference V)
diff --git a/stdlib/source/lux/concurrency/frp.lux b/stdlib/source/lux/concurrency/frp.lux
index 45b9e1839..14563e534 100644
--- a/stdlib/source/lux/concurrency/frp.lux
+++ b/stdlib/source/lux/concurrency/frp.lux
@@ -9,9 +9,9 @@
                 applicative
                 monad
                 eq)
-       (codata [io #- run]
-               function)
-       (data (struct [list])
+       [io #- run]
+       (codata function)
+       (data (coll [list])
              text/format)
        [compiler]
        (macro ["s" syntax #+ syntax: Syntax]))
diff --git a/stdlib/source/lux/concurrency/promise.lux b/stdlib/source/lux/concurrency/promise.lux
index 1d33ee4ee..60cffe2fe 100644
--- a/stdlib/source/lux/concurrency/promise.lux
+++ b/stdlib/source/lux/concurrency/promise.lux
@@ -5,12 +5,12 @@
 
 (;module:
   lux
-  (lux (data (struct [list #* "" Functor<List>])
+  (lux (data (coll [list #* "" Functor<List>])
              number
              text/format
              error)
-       (codata [io #- run]
-               function)
+       [io #- run]
+       (codata function)
        (control functor
                 applicative
                 monad)
diff --git a/stdlib/source/lux/concurrency/stm.lux b/stdlib/source/lux/concurrency/stm.lux
index 06912a25a..b088bd607 100644
--- a/stdlib/source/lux/concurrency/stm.lux
+++ b/stdlib/source/lux/concurrency/stm.lux
@@ -8,10 +8,10 @@
   (lux (control functor
                 applicative
                 monad)
-       (codata [io #- run])
-       (data (struct [list #* "List/" Functor<List>]
-                     [dict #+ Dict]
-                     ["Q" queue])
+       [io #- run]
+       (data (coll [list #* "List/" Functor<List>]
+                   [dict #+ Dict]
+                   ["Q" queue])
              [product]
              [text]
              maybe
diff --git a/stdlib/source/lux/control/comonad.lux b/stdlib/source/lux/control/comonad.lux
index 046511190..00d807ef1 100644
--- a/stdlib/source/lux/control/comonad.lux
+++ b/stdlib/source/lux/control/comonad.lux
@@ -6,7 +6,7 @@
 (;module:
   lux
   ["F" ../functor]
-  [lux/data/struct/list #* "" Fold<List>])
+  [lux/data/coll/list #* "" Fold<List>])
 
 ## [Signatures]
 (sig: #export (CoMonad w)
diff --git a/stdlib/source/lux/data/char.lux b/stdlib/source/lux/data/char.lux
index 9c9baaf20..49c247f93 100644
--- a/stdlib/source/lux/data/char.lux
+++ b/stdlib/source/lux/data/char.lux
@@ -65,13 +65,13 @@
                (or (n.= +4 size)
                    (n.= +5 size)))
         (if (n.= +4 size)
-          (case (text;at +2 y)
+          (case (text;nth +2 y)
             #;None
             (#;Left (Text/append "Wrong syntax for Char: " y))
 
             (#;Some char)
             (#;Right char))
-          (case [(text;at +2 y) (text;at +3 y)]
+          (case [(text;nth +2 y) (text;nth +3 y)]
             [(#;Some #"\\") (#;Some char)]
             (case char
               #"t" (#;Right #"\t")
diff --git a/stdlib/source/lux/data/struct/array.lux b/stdlib/source/lux/data/coll/array.lux
index fa52df9f1..f95754262 100644
--- a/stdlib/source/lux/data/struct/array.lux
+++ b/stdlib/source/lux/data/coll/array.lux
@@ -12,7 +12,7 @@
                 eq
                 fold)
        (data error
-             (struct [list "List/" Fold<List>])
+             (coll [list "List/" Fold<List>])
              [product])
        ))
 
diff --git a/stdlib/source/lux/data/struct/dict.lux b/stdlib/source/lux/data/coll/dict.lux
index 3b153d229..fe77d0bea 100644
--- a/stdlib/source/lux/data/struct/dict.lux
+++ b/stdlib/source/lux/data/coll/dict.lux
@@ -8,8 +8,8 @@
   (lux (control hash
                 eq)
        (data maybe
-             (struct [list "List/" Fold<List> Functor<List> Monoid<List>]
-                     [array #+ Array "Array/" Functor<Array> Fold<Array>])
+             (coll [list "List/" Fold<List> Functor<List> Monoid<List>]
+                   [array #+ Array "Array/" Functor<Array> Fold<Array>])
              [bit]
              [product]
              text/format
diff --git a/stdlib/source/lux/data/struct/list.lux b/stdlib/source/lux/data/coll/list.lux
index 3228e1d78..9b0328b16 100644
--- a/stdlib/source/lux/data/struct/list.lux
+++ b/stdlib/source/lux/data/coll/list.lux
@@ -215,7 +215,7 @@
   [every? true  and]
   [any?   false or])
 
-(def: #export (at i xs)
+(def: #export (nth i xs)
   {#;doc "Fetches the element at the specified index."}
   (All [a]
     (-> Nat (List a) (Maybe a)))
@@ -226,7 +226,7 @@
     (#;Cons [x xs'])
     (if (n.= +0 i)
       (#;Some x)
-      (at (n.dec i) xs'))))
+      (nth (n.dec i) xs'))))
 
 ## [Structures]
 (struct: #export (Eq<List> Eq<a>)
diff --git a/stdlib/source/lux/data/struct/queue.lux b/stdlib/source/lux/data/coll/queue.lux
index 1c7fcdc3e..4dcac337c 100644
--- a/stdlib/source/lux/data/struct/queue.lux
+++ b/stdlib/source/lux/data/coll/queue.lux
@@ -6,7 +6,7 @@
 (;module:
   lux
   (lux (control eq)
-       (data (struct [list "List/" Monoid<List>]))))
+       (data (coll [list "List/" Monoid<List>]))))
 
 ## [Types]
 (type: #export (Queue a)
diff --git a/stdlib/source/lux/data/struct/set.lux b/stdlib/source/lux/data/coll/set.lux
index 711ae4553..952e8f055 100644
--- a/stdlib/source/lux/data/struct/set.lux
+++ b/stdlib/source/lux/data/coll/set.lux
@@ -10,8 +10,8 @@
                 monad
                 eq
                 [hash #*])
-       (data (struct [dict]
-                     [list "List/" Fold<List> Functor<List>]))
+       (data (coll [dict]
+                   [list "List/" Fold<List> Functor<List>]))
        (codata function)))
 
 ## [Types]
diff --git a/stdlib/source/lux/data/struct/stack.lux b/stdlib/source/lux/data/coll/stack.lux
index e62a74590..05364b832 100644
--- a/stdlib/source/lux/data/struct/stack.lux
+++ b/stdlib/source/lux/data/coll/stack.lux
@@ -5,7 +5,7 @@
 
 (;module:
   lux
-  (lux (data (struct [list]))))
+  (lux (data (coll [list]))))
 
 ## [Types]
 (type: #export (Stack a)
diff --git a/stdlib/source/lux/data/struct/tree/rose.lux b/stdlib/source/lux/data/coll/tree/rose.lux
index 8620e46a7..4c4f873d5 100644
--- a/stdlib/source/lux/data/struct/tree/rose.lux
+++ b/stdlib/source/lux/data/coll/tree/rose.lux
@@ -7,7 +7,7 @@
   lux
   (lux (control monad
                 eq)
-       (data (struct [list "" Monad<List>]))
+       (data (coll [list "" Monad<List>]))
        [compiler]
        (macro [ast]
               ["s" syntax #+ syntax: Syntax])))
diff --git a/stdlib/source/lux/data/struct/tree/zipper.lux b/stdlib/source/lux/data/coll/tree/zipper.lux
index 74dbd024f..c154ed19c 100644
--- a/stdlib/source/lux/data/struct/tree/zipper.lux
+++ b/stdlib/source/lux/data/coll/tree/zipper.lux
@@ -5,9 +5,9 @@
 
 (;module:
   lux
-  (lux (data (struct [list "" Monad<List> Fold<List> "List/" Monoid<List>]
-                     (tree [rose #+ Tree])
-                     [stack #+ Stack]))
+  (lux (data (coll [list "" Monad<List> Fold<List> "List/" Monoid<List>]
+                   (tree [rose #+ Tree])
+                   [stack #+ Stack]))
        [compiler]
        (macro [ast]
               ["s" syntax #+ syntax: Syntax])))
diff --git a/stdlib/source/lux/data/struct/vector.lux b/stdlib/source/lux/data/coll/vector.lux
index 9a22efb93..1dbceb97e 100644
--- a/stdlib/source/lux/data/struct/vector.lux
+++ b/stdlib/source/lux/data/coll/vector.lux
@@ -12,8 +12,8 @@
                 monoid
                 fold)
        (data maybe
-             (struct [list "List/" Fold<List> Functor<List> Monoid<List>]
-                     [array #+ Array "Array/" Functor<Array> Fold<Array>])
+             (coll [list "List/" Fold<List> Functor<List> Monoid<List>]
+                   [array #+ Array "Array/" Functor<Array> Fold<Array>])
              [bit]
              [number "Int/" Number<Int>]
              [product])
@@ -255,7 +255,7 @@
             (error! "Incorrect vector structure."))))
       #;None)))
 
-(def: #export (at idx vec)
+(def: #export (nth idx vec)
   (All [a] (-> Nat (Vector a) (Maybe a)))
   (do Monad<Maybe>
     [base (base-for idx vec)]
@@ -276,7 +276,7 @@
 
 (def: #export (update idx f vec)
   (All [a] (-> Nat (-> a a) (Vector a) (Vector a)))
-  (case (at idx vec)
+  (case (nth idx vec)
     (#;Some val)
     (put idx (f val) vec)
 
diff --git a/stdlib/source/lux/data/format/json.lux b/stdlib/source/lux/data/format/json.lux
index 66ad6c093..0c61b958b 100644
--- a/stdlib/source/lux/data/format/json.lux
+++ b/stdlib/source/lux/data/format/json.lux
@@ -21,9 +21,9 @@
              [error #- fail]
              [sum]
              [product]
-             (struct [list "" Fold<List> "List/" Monad<List>]
-                     [vector #+ Vector vector "Vector/" Monad<Vector>]
-                     [dict #+ Dict]))
+             (coll [list "" Fold<List> "List/" Monad<List>]
+                   [vector #+ Vector vector "Vector/" Monad<Vector>]
+                   [dict #+ Dict]))
        (codata [function])
        [compiler #+ Monad<Lux> with-gensyms]
        (macro [syntax #+ syntax:]
@@ -544,13 +544,13 @@
       _
       (#;Left (format "JSON value is not an object: " (show-json json))))))
 
-(def: #export (at idx parser)
+(def: #export (nth idx parser)
   {#;doc "Parses an element inside a JSON array."}
   (All [a] (-> Nat (Parser a) (Parser a)))
   (lambda [json]
     (case json
       (#Array values)
-      (case (vector;at idx values)
+      (case (vector;nth idx values)
         (#;Some value)
         (case (parser value)
           (#;Right output)
@@ -689,8 +689,8 @@
                    (and prev
                         (default false
                           (do Monad<Maybe>
-                            [x' (vector;at idx xs)
-                             y' (vector;at idx ys)]
+                            [x' (vector;nth idx xs)
+                             y' (vector;nth idx ys)]
                             (wrap (= x' y'))))))
                  true
                  (list;indices (vector;size xs))))
@@ -734,7 +734,7 @@
           parsers (|> parts
                       (list;zip2 (list;indices array-size))
                       (List/map (lambda [[idx parser]]
-                                  (` (at (~ (ast;nat idx)) (~ parser))))))]
+                                  (` (nth (~ (ast;nat idx)) (~ parser))))))]
       (wrap (list (` ($_ seq (~@ parsers))))))
 
     (#ObjectShape kvs)
@@ -757,7 +757,7 @@
           parsers (|> parts
                       (list;zip2 (list;indices array-size))
                       (List/map (lambda [[idx parser]]
-                                  (` (at (~ (ast;nat idx)) (~ parser))))))]
+                                  (` (nth (~ (ast;nat idx)) (~ parser))))))]
       (wrap (list (` (ensure (array-size! (~ (ast;nat array-size)))
                              ($_ seq (~@ parsers)))))))
 
@@ -998,8 +998,8 @@
                                           [#let [tag (ast;tag name)]
                                            decoder (Codec<JSON,?>//decode new-*env* :case:)]
                                           (wrap (list (` (do Monad<Parser>
-                                                           [(~ g!_) (;;at +0 (;;text! (~ (ast;text (product;right name)))))
-                                                            (~ g!_) (;;at +1 (~ decoder))]
+                                                           [(~ g!_) (;;nth +0 (;;text! (~ (ast;text (product;right name)))))
+                                                            (~ g!_) (;;nth +1 (~ decoder))]
                                                            ((~ (' wrap)) ((~ tag) (~ g!_)))))))))
                                       members)
                #let [:x:+ (case g!vars
diff --git a/stdlib/source/lux/data/text.lux b/stdlib/source/lux/data/text.lux
index 85d5d9dd5..adc0454b2 100644
--- a/stdlib/source/lux/data/text.lux
+++ b/stdlib/source/lux/data/text.lux
@@ -11,7 +11,7 @@
                 monad
                 codec
                 hash)
-       (data (struct [list])
+       (data (coll [list])
              maybe)))
 
 ## [Functions]
@@ -19,7 +19,7 @@
   (-> Text Nat)
   (int-to-nat (_lux_proc ["jvm" "i2l"] [(_lux_proc ["jvm" "invokevirtual:java.lang.String:length:"] [x])])))
 
-(def: #export (at idx x)
+(def: #export (nth idx x)
   (-> Nat Text (Maybe Char))
   (if (n.< (size x) idx)
     (#;Some (_lux_proc ["jvm" "invokevirtual:java.lang.String:charAt:int"] [x (_lux_proc ["jvm" "l2i"] [(nat-to-int idx)])]))
diff --git a/stdlib/source/lux/data/text/format.lux b/stdlib/source/lux/data/text/format.lux
index 2ae5c62ca..732de0db4 100644
--- a/stdlib/source/lux/data/text/format.lux
+++ b/stdlib/source/lux/data/text/format.lux
@@ -11,7 +11,7 @@
              [number]
              [text]
              [ident]
-             (struct [list "" Monad<List>]))
+             (coll [list "" Monad<List>]))
        [type]
        [compiler]
        (macro [ast]
diff --git a/stdlib/source/lux/control/effect.lux b/stdlib/source/lux/effect.lux
index 2b81ad543..de3038927 100644
--- a/stdlib/source/lux/control/effect.lux
+++ b/stdlib/source/lux/effect.lux
@@ -8,8 +8,8 @@
   (lux (control ["F" functor]
                 applicative
                 monad)
-       (codata [io #- run])
-       (data (struct [list "List/" Monad<List> Monoid<List>])
+       [io #- run]
+       (data (coll [list "List/" Monad<List> Monoid<List>])
              [number "Nat/" Codec<Text,Nat>]
              text/format
              error
@@ -217,7 +217,7 @@
 (def: translation^
   (Syntax Translation)
   (s;form (do s;Monad<Syntax>
-            [_ (s;sample! (' =>))]
+            [_ (s;this! (' =>))]
             (s;seq s;symbol
                    (s;tuple (s;seq s;any
                                    s;any))))))
diff --git a/stdlib/source/lux/host.lux b/stdlib/source/lux/host.lux
index ededaa0a4..58d163c2e 100644
--- a/stdlib/source/lux/host.lux
+++ b/stdlib/source/lux/host.lux
@@ -7,10 +7,10 @@
   lux
   (lux (control monad
                 [enum])
-       (codata function
-               [io #+ IO Monad<IO> io])
-       (data (struct [list #* "" Functor<List> Fold<List> "List/" Monad<List> Monoid<List>]
-                     [array #+ Array])
+       [io #+ IO Monad<IO> io]
+       (codata function)
+       (data (coll [list #* "" Functor<List> Fold<List> "List/" Monad<List> Monoid<List>]
+                   [array #+ Array])
              number
              maybe
              [product]
@@ -561,14 +561,14 @@
   (-> Text Text (Syntax AST))
   (do s;Monad<Syntax>
     [#let [dotted-name (format "." field-name)]
-     _ (s;sample! (ast;symbol ["" dotted-name]))]
+     _ (s;this! (ast;symbol ["" dotted-name]))]
     (wrap (`' (_lux_proc ["jvm" (~ (ast;text (format "getstatic" ":" class-name ":" field-name)))] [])))))
 
 (def: (make-get-var-parser class-name field-name)
   (-> Text Text (Syntax AST))
   (do s;Monad<Syntax>
     [#let [dotted-name (format "." field-name)]
-     _ (s;sample! (ast;symbol ["" dotted-name]))]
+     _ (s;this! (ast;symbol ["" dotted-name]))]
     (wrap (`' (_lux_proc ["jvm" (~ (ast;text (format "getfield" ":" class-name ":" field-name)))] [_jvm_this])))))
 
 (def: (make-put-var-parser class-name field-name)
@@ -576,7 +576,7 @@
   (do s;Monad<Syntax>
     [#let [dotted-name (format "." field-name)]
      [_ _ value] (: (Syntax [Unit Unit AST])
-                    (s;form ($_ s;seq (s;sample! (' :=)) (s;sample! (ast;symbol ["" dotted-name])) s;any)))]
+                    (s;form ($_ s;seq (s;this! (' :=)) (s;this! (ast;symbol ["" dotted-name])) s;any)))]
     (wrap (`' (_lux_proc ["jvm" (~ (ast;text (format "putfield" ":" class-name ":" field-name)))] [_jvm_this (~ value)])))))
 
 (def: (pre-walk-replace f input)
@@ -621,7 +621,7 @@
   (-> (List TypeParam) Text (List ArgDecl) (Syntax AST))
   (do s;Monad<Syntax>
     [[_ args] (: (Syntax [Unit (List AST)])
-                 (s;form ($_ s;seq (s;sample! (' .new!)) (s;tuple (s;exactly (list;size arg-decls) s;any)))))
+                 (s;form ($_ s;seq (s;this! (' .new!)) (s;tuple (s;exactly (list;size arg-decls) s;any)))))
      #let [arg-decls' (: (List Text) (map (. (simple-class$ params) product;right) arg-decls))]]
     (wrap (` (;_lux_proc ["jvm" (~ (ast;text (format "new" ":" class-name ":" (text;join-with "," arg-decls'))))]
                          [(~@ args)])))))
@@ -631,7 +631,7 @@
   (do s;Monad<Syntax>
     [#let [dotted-name (format "." method-name "!")]
      [_ args] (: (Syntax [Unit (List AST)])
-                 (s;form ($_ s;seq (s;sample! (ast;symbol ["" dotted-name])) (s;tuple (s;exactly (list;size arg-decls) s;any)))))
+                 (s;form ($_ s;seq (s;this! (ast;symbol ["" dotted-name])) (s;tuple (s;exactly (list;size arg-decls) s;any)))))
      #let [arg-decls' (: (List Text) (map (. (simple-class$ params) product;right) arg-decls))]]
     (wrap (`' (;_lux_proc ["jvm" (~ (ast;text (format "invokestatic" ":" class-name ":" method-name ":" (text;join-with "," arg-decls'))))]
                           [(~@ args)])))))
@@ -642,7 +642,7 @@
      (do s;Monad<Syntax>
        [#let [dotted-name (format "." method-name "!")]
         [_ args] (: (Syntax [Unit (List AST)])
-                    (s;form ($_ s;seq (s;sample! (ast;symbol ["" dotted-name])) (s;tuple (s;exactly (list;size arg-decls) s;any)))))
+                    (s;form ($_ s;seq (s;this! (ast;symbol ["" dotted-name])) (s;tuple (s;exactly (list;size arg-decls) s;any)))))
         #let [arg-decls' (: (List Text) (map (. (simple-class$ params) product;right) arg-decls))]]
        (wrap (`' (;_lux_proc ["jvm" (~ (ast;text (format <jvm-op> ":" class-name ":" method-name ":" (text;join-with "," arg-decls'))))]
                              [(~' _jvm_this) (~@ args)])))))]
@@ -680,32 +680,32 @@
   (Syntax PrivacyModifier)
   (let [(^open) s;Monad<Syntax>]
     ($_ s;alt
-        (s;sample! (' #public))
-        (s;sample! (' #private))
-        (s;sample! (' #protected))
+        (s;this! (' #public))
+        (s;this! (' #private))
+        (s;this! (' #protected))
         (wrap []))))
 
 (def: inheritance-modifier^
   (Syntax InheritanceModifier)
   (let [(^open) s;Monad<Syntax>]
     ($_ s;alt
-        (s;sample! (' #final))
-        (s;sample! (' #abstract))
+        (s;this! (' #final))
+        (s;this! (' #abstract))
         (wrap []))))
 
 (def: bound-kind^
   (Syntax BoundKind)
-  (s;alt (s;sample! (' <))
-         (s;sample! (' >))))
+  (s;alt (s;this! (' <))
+         (s;this! (' >))))
 
 (def: (generic-type^ imports type-vars)
   (-> ClassImports (List TypeParam) (Syntax GenericType))
   ($_ s;either
       (do s;Monad<Syntax>
-        [_ (s;sample! (' ?))]
+        [_ (s;this! (' ?))]
         (wrap (#GenericWildcard #;None)))
       (s;tuple (do s;Monad<Syntax>
-                 [_ (s;sample! (' ?))
+                 [_ (s;this! (' ?))
                   bound-kind bound-kind^
                   bound (generic-type^ imports type-vars)]
                  (wrap (#GenericWildcard (#;Some [bound-kind bound])))))
@@ -731,7 +731,7 @@
                 ## else
                 (wrap (#GenericClass name (list))))))
       (s;form (do s;Monad<Syntax>
-                [name (s;sample! (' Array))
+                [name (s;this! (' Array))
                  component (generic-type^ imports type-vars)]
                 (case component
                   (^template [<class> <name>]
@@ -763,7 +763,7 @@
               (wrap [param-name (list)]))
             (s;tuple (do s;Monad<Syntax>
                        [param-name s;local-symbol
-                        _ (s;sample! (' <))
+                        _ (s;this! (' <))
                         bounds (s;many (generic-type^ imports (list)))]
                        (wrap [param-name bounds])))))
 
@@ -807,7 +807,7 @@
 (def: (annotations^' imports)
   (-> ClassImports (Syntax (List Annotation)))
   (do s;Monad<Syntax>
-    [_ (s;sample! (' #ann))]
+    [_ (s;this! (' #ann))]
     (s;tuple (s;some (annotation^ imports)))))
 
 (def: (annotations^ imports)
@@ -819,7 +819,7 @@
 (def: (throws-decl'^ imports type-vars)
   (-> ClassImports (List TypeParam) (Syntax (List GenericType)))
   (do s;Monad<Syntax>
-    [_ (s;sample! (' #throws))]
+    [_ (s;this! (' #throws))]
     (s;tuple (s;some (generic-type^ imports type-vars)))))
 
 (def: (throws-decl^ imports type-vars)
@@ -845,14 +845,14 @@
 (def: state-modifier^
   (Syntax StateModifier)
   ($_ s;alt
-      (s;sample! (' #volatile))
-      (s;sample! (' #final))
+      (s;this! (' #volatile))
+      (s;this! (' #final))
       (:: s;Monad<Syntax> wrap [])))
 
 (def: (field-decl^ imports type-vars)
   (-> ClassImports (List TypeParam) (Syntax [MemberDecl FieldDecl]))
   (s;either (s;form (do s;Monad<Syntax>
-                      [_ (s;sample! (' #const))
+                      [_ (s;this! (' #const))
                        name s;local-symbol
                        anns (annotations^ imports)
                        type (generic-type^ imports type-vars)
@@ -887,10 +887,10 @@
   (-> ClassImports (List TypeParam) (Syntax [MemberDecl MethodDef]))
   (s;form (do s;Monad<Syntax>
             [pm privacy-modifier^
-             strict-fp? (s;sample? (' #strict))
+             strict-fp? (s;this? (' #strict))
              method-vars (s;default (list) (type-params^ imports))
              #let [total-vars (List/append class-vars method-vars)]
-             [_ arg-decls] (s;form (s;seq (s;sample! (' new))
+             [_ arg-decls] (s;form (s;seq (s;this! (' new))
                                           (arg-decls^ imports total-vars)))
              constructor-args (constructor-args^ imports total-vars)
              exs (throws-decl^ imports total-vars)
@@ -905,8 +905,8 @@
   (-> ClassImports (List TypeParam) (Syntax [MemberDecl MethodDef]))
   (s;form (do s;Monad<Syntax>
             [pm privacy-modifier^
-             strict-fp? (s;sample? (' #strict))
-             final? (s;sample? (' #final))
+             strict-fp? (s;this? (' #strict))
+             final? (s;this? (' #final))
              method-vars (s;default (list) (type-params^ imports))
              #let [total-vars (List/append class-vars method-vars)]
              [name arg-decls] (s;form (s;seq s;local-symbol
@@ -923,7 +923,7 @@
 (def: (overriden-method-def^ imports)
   (-> ClassImports (Syntax [MemberDecl MethodDef]))
   (s;form (do s;Monad<Syntax>
-            [strict-fp? (s;sample? (' #strict))
+            [strict-fp? (s;this? (' #strict))
              owner-class (class-decl^ imports)
              method-vars (s;default (list) (type-params^ imports))
              #let [total-vars (List/append (product;right owner-class) method-vars)]
@@ -942,8 +942,8 @@
   (-> ClassImports (Syntax [MemberDecl MethodDef]))
   (s;form (do s;Monad<Syntax>
             [pm privacy-modifier^
-             strict-fp? (s;sample? (' #strict))
-             _ (s;sample! (' #static))
+             strict-fp? (s;this? (' #strict))
+             _ (s;this! (' #static))
              method-vars (s;default (list) (type-params^ imports))
              #let [total-vars method-vars]
              [name arg-decls] (s;form (s;seq s;local-symbol
@@ -961,7 +961,7 @@
   (-> ClassImports (Syntax [MemberDecl MethodDef]))
   (s;form (do s;Monad<Syntax>
             [pm privacy-modifier^
-             _ (s;sample! (' #abstract))
+             _ (s;this! (' #abstract))
              method-vars (s;default (list) (type-params^ imports))
              #let [total-vars method-vars]
              [name arg-decls] (s;form (s;seq s;local-symbol
@@ -978,7 +978,7 @@
   (-> ClassImports (Syntax [MemberDecl MethodDef]))
   (s;form (do s;Monad<Syntax>
             [pm privacy-modifier^
-             _ (s;sample! (' #native))
+             _ (s;this! (' #native))
              method-vars (s;default (list) (type-params^ imports))
              #let [total-vars method-vars]
              [name arg-decls] (s;form (s;seq s;local-symbol
@@ -1008,42 +1008,42 @@
 (def: class-kind^
   (Syntax ClassKind)
   (s;either (do s;Monad<Syntax>
-              [_ (s;sample! (' #class))]
+              [_ (s;this! (' #class))]
               (wrap #Class))
             (do s;Monad<Syntax>
-              [_ (s;sample! (' #interface))]
+              [_ (s;this! (' #interface))]
               (wrap #Interface))
             ))
 
 (def: import-member-alias^
   (Syntax (Maybe Text))
   (s;opt (do s;Monad<Syntax>
-           [_ (s;sample! (' #as))]
+           [_ (s;this! (' #as))]
            s;local-symbol)))
 
 (def: (import-member-args^ imports type-vars)
   (-> ClassImports (List TypeParam) (Syntax (List [Bool GenericType])))
-  (s;tuple (s;some (s;seq (s;sample? (' #?)) (generic-type^ imports type-vars)))))
+  (s;tuple (s;some (s;seq (s;this? (' #?)) (generic-type^ imports type-vars)))))
 
 (def: import-member-return-flags^
   (Syntax [Bool Bool Bool])
-  ($_ s;seq (s;sample? (' #io)) (s;sample? (' #try)) (s;sample? (' #?))))
+  ($_ s;seq (s;this? (' #io)) (s;this? (' #try)) (s;this? (' #?))))
 
 (def: primitive-mode^
   (Syntax Primitive-Mode)
-  (s;alt (s;sample! (' #manual))
-         (s;sample! (' #auto))))
+  (s;alt (s;this! (' #manual))
+         (s;this! (' #auto))))
 
 (def: (import-member-decl^ imports owner-vars)
   (-> ClassImports (List TypeParam) (Syntax ImportMemberDecl))
   ($_ s;either
       (s;form (do s;Monad<Syntax>
-                [_ (s;sample! (' #enum))
+                [_ (s;this! (' #enum))
                  enum-members (s;some s;local-symbol)]
                 (wrap (#EnumDecl enum-members))))
       (s;form (do s;Monad<Syntax>
                 [tvars (s;default (list) (type-params^ imports))
-                 _ (s;sample! (' new))
+                 _ (s;this! (' new))
                  ?alias import-member-alias^
                  #let [total-vars (List/append owner-vars tvars)]
                  ?prim-mode (s;opt primitive-mode^)
@@ -1061,7 +1061,7 @@
                 ))
       (s;form (do s;Monad<Syntax>
                 [kind (: (Syntax ImportMethodKind)
-                         (s;alt (s;sample! (' #static))
+                         (s;alt (s;this! (' #static))
                                 (wrap [])))
                  tvars (s;default (list) (type-params^ imports))
                  name s;local-symbol
@@ -1083,12 +1083,12 @@
                                      #import-method-return  return
                                      }]))))
       (s;form (do s;Monad<Syntax>
-                [static? (s;sample? (' #static))
+                [static? (s;this? (' #static))
                  name s;local-symbol
                  ?prim-mode (s;opt primitive-mode^)
                  gtype (generic-type^ imports owner-vars)
-                 maybe? (s;sample? (' #?))
-                 setter? (s;sample? (' #!))]
+                 maybe? (s;this? (' #?))
+                 setter? (s;this? (' #!))]
                 (wrap (#FieldAccessDecl {#import-field-mode    (default #AutoPrM ?prim-mode)
                                          #import-field-name    name
                                          #import-field-static? static?
@@ -1251,7 +1251,7 @@
     
     (#OverridenMethod strict-fp? class-decl type-vars arg-decls return-type body exs)
     (let [super-replacer (parser->replacer (s;form (do s;Monad<Syntax>
-                                                     [_ (s;sample! (' .super!))
+                                                     [_ (s;this! (' .super!))
                                                       args (s;tuple (s;exactly (list;size arg-decls) s;any))
                                                       #let [arg-decls' (: (List Text) (map (. (simple-class$ (list)) product;right)
                                                                                            arg-decls))]]
@@ -1944,7 +1944,7 @@
     (compiler;fail (format "Unknown class: " class-name))))
 
 (syntax: #export (jvm-import [#let [imports (class-imports *compiler*)]]
-                   [long-name? (s;sample? (' #long))]
+                   [long-name? (s;this? (' #long))]
                    [class-decl (class-decl^ imports)]
                    [#let [full-class-name (product;left class-decl)
                           imports (add-import [(short-class-name full-class-name) full-class-name]
diff --git a/stdlib/source/lux/codata/io.lux b/stdlib/source/lux/io.lux
index 60ea73834..e395e7c32 100644
--- a/stdlib/source/lux/codata/io.lux
+++ b/stdlib/source/lux/io.lux
@@ -8,7 +8,7 @@
   (lux (control functor
                 applicative
                 monad)
-       (data (struct list))))
+       (data (coll list))))
 
 ## [Types]
 (type: #export (IO a)
diff --git a/stdlib/source/lux/lexer.lux b/stdlib/source/lux/lexer.lux
index ca8f7f5cf..03e5f5cbd 100644
--- a/stdlib/source/lux/lexer.lux
+++ b/stdlib/source/lux/lexer.lux
@@ -15,7 +15,7 @@
              [char "Char/" Ord<Char>]
              maybe
              ["E" error #- fail]
-             (struct [list "" Functor<List>]))))
+             (coll [list "" Functor<List>]))))
 
 ## [Types]
 (type: #export (Lexer a)
@@ -86,7 +86,7 @@
   {#;doc "Just returns the next character without applying any logic."}
   (Lexer Char)
   (lambda [input]
-    (case [(text;at +0 input) (text;split +1 input)]
+    (case [(text;nth +0 input) (text;split +1 input)]
       [(#;Some output) (#;Some [_ input'])]
       (#E;Success [input' output])
 
@@ -276,7 +276,7 @@
   {#;doc "Lex the next character (without consuming it from the input)."}
   (Lexer Char)
   (lambda [input]
-    (case (text;at +0 input)
+    (case (text;nth +0 input)
       (#;Some output)
       (#E;Success [input output])
 
@@ -288,7 +288,7 @@
   {#;doc "Lex a character if it matches the given sample."}
   (-> Char (Lexer Char))
   (lambda [input]
-    (case [(text;at +0 input) (text;split +1 input)]
+    (case [(text;nth +0 input) (text;split +1 input)]
       [(#;Some char') (#;Some [_ input'])]
       (if (Char/= test char')
         (#E;Success [input' test])
@@ -352,7 +352,7 @@
     (case (text;split +1 input)
       (#;Some [init input'])
       (if (text;contains? init options)
-        (case (text;at +0 init)
+        (case (text;nth +0 init)
           (#;Some output)
           (#E;Success [input' output])
 
@@ -370,7 +370,7 @@
     (case (text;split +1 input)
       (#;Some [init input'])
       (if (;not (text;contains? init options))
-        (case (text;at +0 init)
+        (case (text;nth +0 init)
           (#;Some output)
           (#E;Success [input' output])
 
@@ -388,7 +388,7 @@
     (case (: (Maybe [Text Char])
              (do Monad<Maybe>
                [[init input'] (text;split +1 input)
-                output (text;at +0 init)]
+                output (text;nth +0 init)]
                (wrap [input' output])))
       (#;Some [input' output])
       (if (p output)
diff --git a/stdlib/source/lux/lexer/regex.lux b/stdlib/source/lux/lexer/regex.lux
index 5684a4465..503364ce0 100644
--- a/stdlib/source/lux/lexer/regex.lux
+++ b/stdlib/source/lux/lexer/regex.lux
@@ -11,7 +11,7 @@
              text/format
              [number "Int/" Codec<Text,Int>]
              [product]
-             (struct [list "" Fold<List> "List/" Monad<List>]))
+             (coll [list "" Fold<List> "List/" Monad<List>]))
        [compiler #- run]
        (macro [ast]
               [syntax #+ syntax:])
diff --git a/stdlib/source/lux/macro.lux b/stdlib/source/lux/macro.lux
index b06deedb7..54d41b28f 100644
--- a/stdlib/source/lux/macro.lux
+++ b/stdlib/source/lux/macro.lux
@@ -6,14 +6,14 @@
 (;module:
   lux
   (lux (control monad)
-       (data (struct [list "List/" Monad<List>])
+       (data (coll [list "List/" Monad<List>])
              text/format)
        [compiler]
        (macro ["s" syntax #+ syntax: Syntax])))
 
 (def: omit^
   (Syntax Bool)
-  (s;sample? (' #omit)))
+  (s;this? (' #omit)))
 
 (do-template [<macro> <func>]
   [(syntax: #export (<macro> [? omit^] token)
diff --git a/stdlib/source/lux/macro/ast.lux b/stdlib/source/lux/macro/ast.lux
index 821264c09..d284a8043 100644
--- a/stdlib/source/lux/macro/ast.lux
+++ b/stdlib/source/lux/macro/ast.lux
@@ -11,7 +11,7 @@
              [char]
              [text #+ Eq<Text> "Text/" Monoid<Text>]
              ident
-             (struct [list #* "" Functor<List> Fold<List>])
+             (coll [list #* "" Functor<List> Fold<List>])
              )))
 
 ## [Types]
diff --git a/stdlib/source/lux/macro/poly.lux b/stdlib/source/lux/macro/poly.lux
index d194a540b..5420e0328 100644
--- a/stdlib/source/lux/macro/poly.lux
+++ b/stdlib/source/lux/macro/poly.lux
@@ -9,8 +9,8 @@
                 [eq])
        (data [text]
              text/format
-             (struct [list "List/" Fold<List> Monad<List>]
-                     [dict #+ Dict])
+             (coll [list "List/" Fold<List> Monad<List>]
+                   [dict #+ Dict])
              [number]
              [product]
              [bool]
diff --git a/stdlib/source/lux/macro/poly/eq.lux b/stdlib/source/lux/macro/poly/eq.lux
index bdce71d50..a9d7c0fae 100644
--- a/stdlib/source/lux/macro/poly/eq.lux
+++ b/stdlib/source/lux/macro/poly/eq.lux
@@ -9,8 +9,8 @@
                 [eq])
        (data [text]
              text/format
-             (struct [list "List/" Monad<List>]
-                     [dict #+ Dict])
+             (coll [list "List/" Monad<List>]
+                   [dict #+ Dict])
              [number]
              [product]
              [bool]
diff --git a/stdlib/source/lux/macro/poly/functor.lux b/stdlib/source/lux/macro/poly/functor.lux
index e659bb41d..ec06193bf 100644
--- a/stdlib/source/lux/macro/poly/functor.lux
+++ b/stdlib/source/lux/macro/poly/functor.lux
@@ -9,8 +9,8 @@
                 [functor])
        (data [text]
              text/format
-             (struct [list "List/" Monad<List>]
-                     [dict #+ Dict])
+             (coll [list "List/" Monad<List>]
+                   [dict #+ Dict])
              [number]
              [product]
              [bool]
diff --git a/stdlib/source/lux/macro/poly/text-encoder.lux b/stdlib/source/lux/macro/poly/text-encoder.lux
index c538844a7..c197f8e0c 100644
--- a/stdlib/source/lux/macro/poly/text-encoder.lux
+++ b/stdlib/source/lux/macro/poly/text-encoder.lux
@@ -9,8 +9,8 @@
                 [codec])
        (data [text]
              text/format
-             (struct [list "List/" Monad<List>]
-                     [dict #+ Dict])
+             (coll [list "List/" Monad<List>]
+                   [dict #+ Dict])
              [number]
              [product]
              [bool]
diff --git a/stdlib/source/lux/macro/syntax.lux b/stdlib/source/lux/macro/syntax.lux
index ba24b607b..2713de9c1 100644
--- a/stdlib/source/lux/macro/syntax.lux
+++ b/stdlib/source/lux/macro/syntax.lux
@@ -15,7 +15,7 @@
              [number]
              [text "Text/" Monoid<Text>]
              [ident]
-             (struct [list #* "" Functor<List> Fold<List> "List/" Monoid<List>])
+             (coll [list #* "" Functor<List> Fold<List> "List/" Monoid<List>])
              [product]
              [error #- fail]))
   (.. [ast "AST/" Eq<AST>]))
@@ -113,7 +113,7 @@
   [   tag Ident    #;TagS ident;Eq<Ident> "tag"]
   )
 
-(def: #export (sample? ast)
+(def: #export (this? ast)
   {#;doc "Asks if the given AST is the next input."}
   (-> AST (Syntax Bool))
   (lambda [tokens]
@@ -128,7 +128,7 @@
       _
       (#;Right [tokens false]))))
 
-(def: #export (sample! ast)
+(def: #export (this! ast)
   {#;doc "Ensures the given AST is the next input."}
   (-> AST (Syntax Unit))
   (lambda [tokens]
diff --git a/stdlib/source/lux/macro/syntax/common.lux b/stdlib/source/lux/macro/syntax/common.lux
index 96203b4c2..3ebb716c6 100644
--- a/stdlib/source/lux/macro/syntax/common.lux
+++ b/stdlib/source/lux/macro/syntax/common.lux
@@ -8,7 +8,7 @@
                   The goal is to be able to reuse common syntax in macro definitions across libraries."}
   lux
   (lux (control monad)
-       (data (struct [list])
+       (data (coll [list])
              text/format
              [ident "Ident/" Eq<Ident>]
              [product])
@@ -27,8 +27,8 @@
               #export
               #hidden)}
   (Syntax (Maybe Export-Level))
-  (s;opt (s;alt (s;sample! (' #export))
-                (s;sample! (' #hidden)))))
+  (s;opt (s;alt (s;this! (' #export))
+                (s;this! (' #hidden)))))
 
 (def: #export (gen-export-level ?el)
   (-> (Maybe Export-Level) (List AST))
@@ -70,7 +70,7 @@
 (def: check^
   (Syntax [(Maybe AST) AST])
   (s;either (s;form (do s;Monad<Syntax>
-                      [_ (s;sample! (' lux;_lux_:))
+                      [_ (s;this! (' lux;_lux_:))
                        type s;any
                        value s;any]
                       (wrap [(#;Some type) value])))
@@ -83,9 +83,9 @@
 
 (def: (_def-anns^ _)
   (-> Top (Syntax (List [Ident AST])))
-  (s;alt (s;sample! (' #lux;Nil))
+  (s;alt (s;this! (' #lux;Nil))
          (s;form (do s;Monad<Syntax>
-                   [_ (s;sample! (' #lux;Cons))
+                   [_ (s;this! (' #lux;Cons))
                     [head tail] (s;seq (s;tuple (s;seq _def-anns-tag^ s;any))
                                        (_def-anns^ []))]
                    (wrap [head tail])))
@@ -94,10 +94,10 @@
 (def: (flat-list^ _)
   (-> Top (Syntax (List AST)))
   (s;either (do s;Monad<Syntax>
-              [_ (s;sample! (' #lux;Nil))]
+              [_ (s;this! (' #lux;Nil))]
               (wrap (list)))
             (s;form (do s;Monad<Syntax>
-                      [_ (s;sample! (' #lux;Cons))
+                      [_ (s;this! (' #lux;Cons))
                        [head tail] (s;tuple (s;seq s;any s;any))
                        tail (s;local (list tail) (flat-list^ []))]
                       (wrap (#;Cons head tail))))))
@@ -105,13 +105,13 @@
 (def: list-meta^
   (Syntax (List AST))
   (s;form (do s;Monad<Syntax>
-            [_ (s;sample! (' #lux;ListA))]
+            [_ (s;this! (' #lux;ListA))]
             (flat-list^ []))))
 
 (def: text-meta^
   (Syntax Text)
   (s;form (do s;Monad<Syntax>
-            [_ (s;sample! (' #lux;TextA))]
+            [_ (s;this! (' #lux;TextA))]
             s;text)))
 
 (def: (find-def-args meta-data)
@@ -138,7 +138,7 @@
                       (compiler;macro-expand-all def-raw))]
     (s;local me-def-raw
              (s;form (do @
-                       [_ (s;sample! (' lux;_lux_def))
+                       [_ (s;this! (' lux;_lux_def))
                         def-name s;local-symbol
                         [?def-type def-value] check^
                         def-anns s;any
diff --git a/stdlib/source/lux/math.lux b/stdlib/source/lux/math.lux
index d5a03b421..1fdde77e6 100644
--- a/stdlib/source/lux/math.lux
+++ b/stdlib/source/lux/math.lux
@@ -6,7 +6,7 @@
 (;module: {#;doc "Common mathematical constants and functions."}
   lux
   (lux (control monad)
-       (data (struct [list "" Fold<List>])
+       (data (coll [list "" Fold<List>])
              [number "Int/" Number<Int>]
              [product]
              text/format)
@@ -122,7 +122,7 @@
           (s/map ast;tag s;tag))
       (s;form (s;many s;any))
       (s;tuple (s;either (do s;Monad<Syntax>
-                           [_ (s;sample! (' #and))
+                           [_ (s;this! (' #and))
                             init-subject (infix^ [])
                             init-op s;any
                             init-param (infix^ [])
diff --git a/stdlib/source/lux/math/complex.lux b/stdlib/source/lux/math/complex.lux
index 9666abdab..ef91715ad 100644
--- a/stdlib/source/lux/math/complex.lux
+++ b/stdlib/source/lux/math/complex.lux
@@ -16,7 +16,7 @@
              text/format
              error
              maybe
-             (struct [list "List/" Monad<List>]))
+             (coll [list "List/" Monad<List>]))
        [compiler]
        (macro [ast]
               ["s" syntax #+ syntax: Syntax])))
diff --git a/stdlib/source/lux/math/simple.lux b/stdlib/source/lux/math/simple.lux
index f8b059794..45ba0a4a4 100644
--- a/stdlib/source/lux/math/simple.lux
+++ b/stdlib/source/lux/math/simple.lux
@@ -8,7 +8,7 @@
   (lux (control monad)
        (data text/format
              [product]
-             (struct [list]))
+             (coll [list]))
        [compiler]
        (macro [ast]
               ["s" syntax #+ syntax: Syntax])
diff --git a/stdlib/source/lux/pipe.lux b/stdlib/source/lux/pipe.lux
index 12337e3ef..2008971c4 100644
--- a/stdlib/source/lux/pipe.lux
+++ b/stdlib/source/lux/pipe.lux
@@ -6,7 +6,7 @@
 (;module: {#;doc "Composable extensions to the piping macro |> that enhance it with various abilities."}
   lux
   (lux (control monad)
-       (data (struct [list #+ Monad<List> "" Fold<List> "List/" Monad<List>])
+       (data (coll [list #+ Monad<List> "" Fold<List> "List/" Monad<List>])
              maybe)
        [compiler #+ with-gensyms Monad<Lux>]
        (macro ["s" syntax #+ syntax: Syntax]
diff --git a/stdlib/source/lux/random.lux b/stdlib/source/lux/random.lux
index 195255643..468b6a34b 100644
--- a/stdlib/source/lux/random.lux
+++ b/stdlib/source/lux/random.lux
@@ -15,13 +15,13 @@
              text/format
              [product]
              [number]
-             (struct [list "List/" Fold<List>]
-                     ["A" array]
-                     ["D" dict]
-                     ["Q" queue]
-                     ["S" set]
-                     ["ST" stack]
-                     ["V" vector]))
+             (coll [list "List/" Fold<List>]
+                   ["A" array]
+                   ["D" dict]
+                   ["Q" queue]
+                   ["S" set]
+                   ["ST" stack]
+                   ["V" vector]))
        (math ["r" ratio]
              ["c" complex])))
 
@@ -288,7 +288,7 @@
 (def: (swap from to vec)
   (All [a] (-> Nat Nat (V;Vector a) (V;Vector a)))
   (V;put to (default (undefined)
-              (V;at from vec))
+              (V;nth from vec))
          vec))
 
 (def: #export (shuffle seed vector)
diff --git a/stdlib/source/lux/test.lux b/stdlib/source/lux/test.lux
index 9524a2168..3b582815e 100644
--- a/stdlib/source/lux/test.lux
+++ b/stdlib/source/lux/test.lux
@@ -12,12 +12,12 @@
                 applicative
                 monad)
        (concurrency [promise #+ Promise Monad<Promise>])
-       (data (struct [list "List/" Monad<List> Fold<List>])
+       (data (coll [list "List/" Monad<List> Fold<List>])
              [product]
              [text]
              text/format
              [error #- fail "Error/" Monad<Error>])
-       (codata [io #- run])
+       [io #- run]
        ["R" random]
        [host #- try]))
 
@@ -136,10 +136,10 @@
 (def: config^
   (Syntax Test-Config)
   (s;alt (do s;Monad<Syntax>
-           [_ (s;sample! (' #seed))]
+           [_ (s;this! (' #seed))]
            s;nat)
          (do s;Monad<Syntax>
-           [_ (s;sample! (' #times))]
+           [_ (s;this! (' #times))]
            s;nat)))
 
 (def: property-test^
diff --git a/stdlib/source/lux/type.lux b/stdlib/source/lux/type.lux
index cda44670b..7610773b1 100644
--- a/stdlib/source/lux/type.lux
+++ b/stdlib/source/lux/type.lux
@@ -11,7 +11,7 @@
              [ident "Ident/" Eq<Ident>]
              [number "Nat/" Codec<Text,Nat>]
              maybe
-             (struct [list #+ "List/" Monad<List> Monoid<List> Fold<List>]))
+             (coll [list #+ "List/" Monad<List> Monoid<List> Fold<List>]))
        (macro [ast])
        ))
 
@@ -41,7 +41,7 @@
     
     (#;BoundT idx)
     (default (error! (Text/append "Unknown type var: " (Nat/encode idx)))
-      (list;at idx env))
+      (list;nth idx env))
     
     _
     type
diff --git a/stdlib/source/lux/type/auto.lux b/stdlib/source/lux/type/auto.lux
index 2266827c9..28ba34090 100644
--- a/stdlib/source/lux/type/auto.lux
+++ b/stdlib/source/lux/type/auto.lux
@@ -10,8 +10,8 @@
        (data [text "Text/" Eq<Text>]
              text/format
              [number]
-             (struct [list "List/" Monad<List> Fold<List>]
-                     [dict])
+             (coll [list "List/" Monad<List> Fold<List>]
+                   [dict])
              [bool]
              [product])
        [compiler #+ Monad<Lux>]
diff --git a/stdlib/source/lux/type/check.lux b/stdlib/source/lux/type/check.lux
index 25cf19834..78461f7d7 100644
--- a/stdlib/source/lux/type/check.lux
+++ b/stdlib/source/lux/type/check.lux
@@ -15,8 +15,8 @@
              [number]
              maybe
              [product]
-             (struct [list]
-                     [dict])
+             (coll [list]
+                   [dict])
              [error #- fail])
        [type "Type/" Eq<Type>]
        ))