Fixed a bug in the new compiler which allowed the same module to be imported more than once.

49 files changed, 226 insertions, 203 deletions

diff --git a/stdlib/source/library/lux/tool/compiler/default/init.lux b/stdlib/source/library/lux/tool/compiler/default/init.lux
index 1a8617f53..ecd883cfe 100644
--- a/stdlib/source/library/lux/tool/compiler/default/init.lux
+++ b/stdlib/source/library/lux/tool/compiler/default/init.lux
@@ -186,7 +186,7 @@
      post_payload (..get_current_payload pre_payoad)]
     (in [requirements post_payload])))
 
-(def: (iteration archive expander reader source pre_payload)
+(def: (iteration' archive expander reader source pre_payload)
   (All [directive]
     (-> Archive Expander Reader Source (Payload directive)
         (All [anchor expression]
@@ -198,7 +198,7 @@
      [requirements post_payload] (process_directive archive expander pre_payload code)]
     (in [source requirements post_payload])))
 
-(def: (iterate archive expander module source pre_payload aliases)
+(def: (iteration archive expander module source pre_payload aliases)
   (All [directive]
     (-> Archive Expander Module Source (Payload directive) Aliases
         (All [anchor expression]
@@ -208,7 +208,7 @@
     [reader (///directive.lift_analysis
              (..reader module aliases source))]
     (function (_ state)
-      (case (///phase.run' state (..iteration archive expander reader source pre_payload))
+      (case (///phase.run' state (..iteration' archive expander reader source pre_payload))
         (#try.Success [state source&requirements&buffer])
         (#try.Success [state (#.Some source&requirements&buffer)])
 
@@ -243,7 +243,7 @@
                                                        (..begin dependencies hash input))
                            #let [module (get@ #///.module input)]]
                           (loop [iteration (<| (///phase.run' state)
-                                               (..iterate archive expander module source buffer ///syntax.no_aliases))]
+                                               (..iteration archive expander module source buffer ///syntax.no_aliases))]
                             (do !
                               [[state ?source&requirements&temporary_payload] iteration]
                               (case ?source&requirements&temporary_payload
@@ -284,5 +284,5 @@
                                                                                    (get@ #///directive.referrals)
                                                                                    (monad.map ! (execute! archive)))
                                                                              temporary_payload (..get_current_payload temporary_payload)]
-                                                                            (..iterate archive expander module source temporary_payload (..module_aliases analysis_module))))))})]))
+                                                                            (..iteration archive expander module source temporary_payload (..module_aliases analysis_module))))))})]))
                                 )))))}))))
diff --git a/stdlib/source/library/lux/tool/compiler/default/platform.lux b/stdlib/source/library/lux/tool/compiler/default/platform.lux
index 1848c28bc..8a3f17237 100644
--- a/stdlib/source/library/lux/tool/compiler/default/platform.lux
+++ b/stdlib/source/library/lux/tool/compiler/default/platform.lux
@@ -8,7 +8,7 @@
      ["." monad (#+ Monad do)]]
     [control
      ["." function]
-     ["." try (#+ Try) ("#\." functor)]
+     ["." try (#+ Try) ("#\." monad)]
      ["." exception (#+ exception:)]
      [concurrency
       ["." async (#+ Async Resolver) ("#\." monad)]
@@ -366,6 +366,12 @@
        ["Importer" (%.text importer)]
        ["importee" (%.text importee)]))
 
+    (exception: #export (cannot_import_twice {importer Module}
+                                             {duplicates (Set Module)})
+      (exception.report
+       ["Importer" (%.text importer)]
+       ["Duplicates" (%.list %.text (set.to_list duplicates))]))
+
     (def: (verify_dependencies importer importee dependence)
       (-> Module Module Dependence (Try Any))
       (cond (text\= importer importee)
@@ -541,20 +547,34 @@
                                                  module)]
                             (loop [[archive state] [archive state]
                                    compilation (base_compiler (:as ///.Input input))
-                                   all_dependencies (: (List Module)
-                                                       (list))]
-                              (let [new_dependencies (get@ #///.dependencies compilation)
-                                    all_dependencies (list\compose new_dependencies all_dependencies)
-                                    continue! (:sharing [<type_vars>]
-                                                        <Platform>
-                                                        platform
-                                                        
-                                                        (-> <Context> (///.Compilation <State+> .Module Any) (List Module)
-                                                            (Action [Archive <State+>]))
-                                                        (:assume
-                                                         recur))]
-                                (do !
-                                  [[archive state] (case new_dependencies
+                                   all_dependencies (: (Set Module)
+                                                       (set.of_list text.hash (list)))]
+                              (do !
+                                [#let [new_dependencies (get@ #///.dependencies compilation)
+                                       continue! (:sharing [<type_vars>]
+                                                           <Platform>
+                                                           platform
+                                                           
+                                                           (-> <Context> (///.Compilation <State+> .Module Any) (Set Module)
+                                                               (Action [Archive <State+>]))
+                                                           (:assume recur))
+                                       ## TODO: Come up with a less hacky way to prevent duplicate imports.
+                                       ## This currently assumes that all imports will be specified once in a single .module: form.
+                                       ## This might not be the case in the future.
+                                       [all_dependencies duplicates _] (: [(Set Module) (Set Module) Bit]
+                                                                          (list\fold (function (_ new [all duplicates seen_prelude?])
+                                                                                       (if (set.member? all new)
+                                                                                         (if (text\= .prelude_module new)
+                                                                                           (if seen_prelude?
+                                                                                             [all (set.add new duplicates) seen_prelude?]
+                                                                                             [all duplicates true])
+                                                                                           [all (set.add new duplicates) seen_prelude?])
+                                                                                         [(set.add new all) duplicates seen_prelude?]))
+                                                                                     (: [(Set Module) (Set Module) Bit]
+                                                                                        [all_dependencies ..empty (set.empty? all_dependencies)])
+                                                                                     new_dependencies))]
+                                 [archive state] (if (set.empty? duplicates)
+                                                   (case new_dependencies
                                                      #.End
                                                      (in [archive state])
 
@@ -567,36 +587,37 @@
                                                                           (list\map product.left)
                                                                           (list\fold archive.merged archive))]]
                                                        (in [archive (try.assumed
-                                                                     (..updated_state archive state))])))]
-                                  (case ((get@ #///.process compilation)
-                                         ## TODO: The "///directive.set_current_module" below shouldn't be necessary. Remove it ASAP.
-                                         ## TODO: The context shouldn't need to be re-set either.
-                                         (|> (///directive.set_current_module module)
-                                             (///phase.run' state)
-                                             try.assumed
-                                             product.left)
-                                         archive)
-                                    (#try.Success [state more|done])
-                                    (case more|done
-                                      (#.Left more)
-                                      (continue! [archive state] more all_dependencies)
-
-                                      (#.Right [descriptor document output])
-                                      (do !
-                                        [#let [_ (debug.log! (..module_compilation_log module state))
-                                               descriptor (set@ #descriptor.references (set.of_list text.hash all_dependencies) descriptor)]
-                                         _ (..cache_module static platform module_id [descriptor document output])]
-                                        (case (archive.add module [descriptor document output] archive)
-                                          (#try.Success archive)
-                                          (in [archive
-                                               (..with_reset_log state)])
-                                          
-                                          (#try.Failure error)
-                                          (async\in (#try.Failure error)))))
-
-                                    (#try.Failure error)
+                                                                     (..updated_state archive state))])))
+                                                   (async\in (exception.except ..cannot_import_twice [module duplicates])))]
+                                (case ((get@ #///.process compilation)
+                                       ## TODO: The "///directive.set_current_module" below shouldn't be necessary. Remove it ASAP.
+                                       ## TODO: The context shouldn't need to be re-set either.
+                                       (|> (///directive.set_current_module module)
+                                           (///phase.run' state)
+                                           try.assumed
+                                           product.left)
+                                       archive)
+                                  (#try.Success [state more|done])
+                                  (case more|done
+                                    (#.Left more)
+                                    (continue! [archive state] more all_dependencies)
+
+                                    (#.Right [descriptor document output])
                                     (do !
-                                      [_ (ioW.freeze (get@ #&file_system platform) static archive)]
-                                      (async\in (#try.Failure error))))))))))]
+                                      [#let [_ (debug.log! (..module_compilation_log module state))
+                                             descriptor (set@ #descriptor.references all_dependencies descriptor)]
+                                       _ (..cache_module static platform module_id [descriptor document output])]
+                                      (case (archive.add module [descriptor document output] archive)
+                                        (#try.Success archive)
+                                        (in [archive
+                                             (..with_reset_log state)])
+                                        
+                                        (#try.Failure error)
+                                        (async\in (#try.Failure error)))))
+
+                                  (#try.Failure error)
+                                  (do !
+                                    [_ (ioW.freeze (get@ #&file_system platform) static archive)]
+                                    (async\in (#try.Failure error)))))))))]
           (compiler archive.runtime_module compilation_module)))
       )))
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/analysis.lux b/stdlib/source/library/lux/tool/compiler/language/lux/analysis.lux
index 02100305d..7dc985749 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/analysis.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/analysis.lux
@@ -471,7 +471,7 @@
 
 (def: #export (except exception parameters)
   (All [e] (-> (Exception e) e Operation))
-  (..failure (exception.construct exception parameters)))
+  (..failure (exception.error exception parameters)))
 
 (def: #export (assertion exception parameters condition)
   (All [e] (-> (Exception e) e Bit (Operation Any)))
@@ -486,7 +486,7 @@
 
 (def: #export (except' exception parameters)
   (All [e] (-> (Exception e) e (phase.Operation Lux)))
-  (..failure' (exception.construct exception parameters)))
+  (..failure' (exception.error exception parameters)))
 
 (def: #export (with_stack exception message action)
   (All [e o] (-> (Exception e) e (Operation o) (Operation o)))
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/analysis/macro.lux b/stdlib/source/library/lux/tool/compiler/language/lux/analysis/macro.lux
index ecc765794..95f38c760 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/analysis/macro.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/analysis/macro.lux
@@ -16,14 +16,14 @@
 (exception: #export (expansion_failed {macro Name} {inputs (List Code)} {error Text})
   (exception.report
    ["Macro" (%.name macro)]
-   ["Inputs" (exception.enumerate %.code inputs)]
+   ["Inputs" (exception.listing %.code inputs)]
    ["Error" error]))
 
 (exception: #export (must_have_single_expansion {macro Name} {inputs (List Code)} {outputs (List Code)})
   (exception.report
    ["Macro" (%.name macro)]
-   ["Inputs" (exception.enumerate %.code inputs)]
-   ["Outputs" (exception.enumerate %.code outputs)]))
+   ["Inputs" (exception.listing %.code inputs)]
+   ["Outputs" (exception.listing %.code outputs)]))
 
 (type: #export Expander
   (-> Macro (List Code) Lux (Try (Try [Lux (List Code)]))))
@@ -38,7 +38,7 @@
         (#try.Success output)
         
         (#try.Failure error)
-        ((meta.failure (exception.construct ..expansion_failed [name inputs error])) state)))))
+        ((meta.failure (exception.error ..expansion_failed [name inputs error])) state)))))
 
 (def: #export (expand_one expander name macro inputs)
   (-> Expander Name Macro (List Code) (Meta Code))
@@ -49,4 +49,4 @@
       (in single)
 
       _
-      (meta.failure (exception.construct ..must_have_single_expansion [name inputs expansion])))))
+      (meta.failure (exception.error ..must_have_single_expansion [name inputs expansion])))))
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/generation.lux b/stdlib/source/library/lux/tool/compiler/language/lux/generation.lux
index bbe6da451..856a044fb 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/generation.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/generation.lux
@@ -258,7 +258,7 @@
   (exception.report
    ["Definition" (name.short name)]
    ["Module" (name.module name)]
-   ["Known Definitions" (exception.enumerate function.identity known_definitions)]))
+   ["Known Definitions" (exception.listing function.identity known_definitions)]))
 
 (def: #export (remember archive name)
   (All [anchor expression directive]
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/case.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/case.lux
index c7b843385..fe7de804f 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/case.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/case.lux
@@ -255,7 +255,7 @@
                 size_sum (list.size flat_sum)
                 num_cases (maybe.else size_sum num_tags)
                 idx (/.tag lefts right?)]
-            (.case (list.nth idx flat_sum)
+            (.case (list.item idx flat_sum)
               (^multi (#.Some caseT)
                       (n.< num_cases idx))
               (do ///.monad
@@ -288,7 +288,7 @@
     (/.with_location location
       (do ///.monad
         [tag (///extension.lift (meta.normal tag))
-         [idx group variantT] (///extension.lift (meta.resolve_tag tag))
+         [idx group variantT] (///extension.lift (meta.tag tag))
          _ (//type.with_env
              (check.check inputT variantT))
          #let [[lefts right?] (/.choice (list.size group) idx)]]
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/case/coverage.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/case/coverage.lux
index 7799be183..a0d02badc 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/case/coverage.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/case/coverage.lux
@@ -1,12 +1,12 @@
 (.module:
   [library
-   [lux #*
+   [lux (#- Variant)
     [abstract
      equivalence
      ["." monad (#+ do)]]
     [control
      ["." try (#+ Try) ("#\." monad)]
-     ["ex" exception (#+ exception:)]]
+     ["." exception (#+ exception:)]]
     [data
      ["." bit ("#\." equivalence)]
      ["." maybe]
@@ -166,8 +166,9 @@
 ## Because of that, the presence of redundant patterns is assumed to
 ## be a bug, likely due to programmer carelessness.
 (exception: #export (redundant_pattern {so_far Coverage} {addition Coverage})
-  (ex.report ["Coverage so-far" (%coverage so_far)]
-             ["Coverage addition" (%coverage addition)]))
+  (exception.report
+   ["Coverage so-far" (%coverage so_far)]
+   ["Coverage addition" (%coverage addition)]))
 
 (def: (flat_alt coverage)
   (-> Coverage (List Coverage))
@@ -210,8 +211,9 @@
 (open: "coverage/." ..equivalence)
 
 (exception: #export (variants_do_not_match {addition_cases Nat} {so_far_cases Nat})
-  (ex.report ["So-far Cases" (%.nat so_far_cases)]
-             ["Addition Cases" (%.nat addition_cases)]))
+  (exception.report
+   ["So-far Cases" (%.nat so_far_cases)]
+   ["Addition Cases" (%.nat addition_cases)]))
 
 ## After determining the coverage of each individual pattern, it is
 ## necessary to merge them all to figure out if the entire
@@ -234,10 +236,10 @@
       (cond (and (known_cases? addition_cases)
                  (known_cases? so_far_cases)
                  (not (n.= addition_cases so_far_cases)))
-            (ex.except ..variants_do_not_match [addition_cases so_far_cases])
+            (exception.except ..variants_do_not_match [addition_cases so_far_cases])
 
             (\ (dictionary.equivalence ..equivalence) = casesSF casesA)
-            (ex.except ..redundant_pattern [so_far addition])
+            (exception.except ..redundant_pattern [so_far addition])
 
             ## else
             (do {! try.monad}
@@ -291,11 +293,11 @@
 
       ## There is nothing the addition adds to the coverage.
       [#1 #1]
-      (ex.except ..redundant_pattern [so_far addition]))
+      (exception.except ..redundant_pattern [so_far addition]))
 
     ## The addition cannot possibly improve the coverage.
     [_ #Exhaustive]
-    (ex.except ..redundant_pattern [so_far addition])
+    (exception.except ..redundant_pattern [so_far addition])
 
     ## The addition completes the coverage.
     [#Exhaustive _]
@@ -304,7 +306,7 @@
     ## The left part will always match, so the addition is redundant.
     (^multi [(#Seq left right) single]
             (coverage/= left single))
-    (ex.except ..redundant_pattern [so_far addition])
+    (exception.except ..redundant_pattern [so_far addition])
 
     ## The right part is not necessary, since it can always match the left.
     (^multi [single (#Seq left right)]
@@ -368,6 +370,6 @@
     _
     (if (coverage/= so_far addition)
       ## The addition cannot possibly improve the coverage.
-      (ex.except ..redundant_pattern [so_far addition])
+      (exception.except ..redundant_pattern [so_far addition])
       ## There are now 2 alternative paths.
       (try\in (#Alt so_far addition)))))
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/function.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/function.lux
index 7fb985f4b..d50f72630 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/function.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/function.lux
@@ -58,7 +58,7 @@
             (recur value)
 
             #.None
-            (/.failure (ex.construct cannot_analyse [expectedT function_name arg_name body])))
+            (/.failure (ex.error cannot_analyse [expectedT function_name arg_name body])))
 
           (^template [<tag> <instancer>]
             [(<tag> _)
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/inference.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/inference.lux
index 05a147c3d..8daf5242f 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/inference.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/inference.lux
@@ -37,7 +37,7 @@
 (exception: #export (cannot_infer {type Type} {args (List Code)})
   (exception.report
    ["Type" (%.type type)]
-   ["Arguments" (exception.enumerate %.code args)]))
+   ["Arguments" (exception.listing %.code args)]))
 
 (exception: #export (cannot_infer_argument {inferred Type} {argument Code})
   (exception.report
@@ -264,7 +264,7 @@
         (cond (or (n.= expected_size actual_size)
                   (and (n.> expected_size actual_size)
                        (n.< boundary tag)))
-              (case (list.nth tag cases)
+              (case (list.item tag cases)
                 (#.Some caseT)
                 (///\in (if (n.= 0 depth)
                           (type.function (list caseT) currentT)
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/module.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/module.lux
index 0af3736ac..b0d9920df 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/module.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/module.lux
@@ -67,7 +67,7 @@
    ["Old annotations" (%.code old)]
    ["New annotations" (%.code new)]))
 
-(def: #export (new hash)
+(def: #export (empty hash)
   (-> Nat Module)
   {#.module_hash        hash
    #.module_aliases     (list)
@@ -158,7 +158,7 @@
   (///extension.lift
    (function (_ state)
      (#try.Success [(update@ #.modules
-                             (plist.put name (new hash))
+                             (plist.put name (..empty hash))
                              state)
                     []]))))
 
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/structure.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/structure.lux
index 4ecca3d1a..1a787efec 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/structure.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/structure.lux
@@ -102,7 +102,7 @@
           (case expectedT
             (#.Sum _)
             (let [flat (type.flat_variant expectedT)]
-              (case (list.nth tag flat)
+              (case (list.item tag flat)
                 (#.Some variant_type)
                 (do !
                   [valueA (//type.with_type variant_type
@@ -263,7 +263,7 @@
   (-> Phase Name Phase)
   (do {! ///.monad}
     [tag (///extension.lift (meta.normal tag))
-     [idx group variantT] (///extension.lift (meta.resolve_tag tag))
+     [idx group variantT] (///extension.lift (meta.tag tag))
      #let [case_size (list.size group)
            [lefts right?] (/.choice case_size idx)]
      expectedT (///extension.lift meta.expected_type)]
@@ -308,7 +308,7 @@
     (#.Item [head_k head_v] _)
     (do {! ///.monad}
       [head_k (///extension.lift (meta.normal head_k))
-       [_ tag_set recordT] (///extension.lift (meta.resolve_tag head_k))
+       [_ tag_set recordT] (///extension.lift (meta.tag head_k))
        #let [size_record (list.size record)
              size_ts (list.size tag_set)]
        _ (if (n.= size_ts size_record)
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension.lux
index aa78e8ade..60f625250 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension.lux
@@ -73,7 +73,7 @@
 (exception: #export [a] (invalid_syntax {name Name} {%format (Format a)} {inputs (List a)})
   (exception.report
    ["Extension" (%.text name)]
-   ["Inputs" (exception.enumerate %format inputs)]))
+   ["Inputs" (exception.listing %format inputs)]))
 
 (exception: #export [s i o] (unknown {name Name} {bundle (Bundle s i o)})
   (exception.report
@@ -81,7 +81,7 @@
    ["Available" (|> bundle
                     dictionary.keys
                     (list.sort text\<)
-                    (exception.enumerate %.text))]))
+                    (exception.listing %.text))]))
 
 (type: #export (Extender s i o)
   (-> Any (Handler s i o)))
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/analysis/jvm.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/analysis/jvm.lux
index 0a60511ab..8d38f4754 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/analysis/jvm.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/analysis/jvm.lux
@@ -230,8 +230,8 @@
      (exception.report
       ["Class" class]
       ["Method" method]
-      ["Arguments" (exception.enumerate ..signature inputsJT)]
-      ["Hints" (exception.enumerate %.type (list\map product.left hints))]))]
+      ["Arguments" (exception.listing ..signature inputsJT)]
+      ["Hints" (exception.listing %.type (list\map product.left hints))]))]
 
   [no_candidates]
   [too_many_candidates]
@@ -1589,7 +1589,7 @@
 (template [<name>]
   [(exception: #export (<name> {methods (List [Text (Type Method)])})
      (exception.report
-      ["Methods" (exception.enumerate
+      ["Methods" (exception.listing
                   (function (_ [name type])
                     (format (%.text name) " " (..signature type)))
                   methods)]))]
@@ -1889,7 +1889,7 @@
 (exception: #export (unknown_super {name Text} {supers (List (Type Class))})
   (exception.report
    ["Name" (%.text name)]
-   ["Available" (exception.enumerate (|>> jvm_parser.read_class product.left) supers)]))
+   ["Available" (exception.listing (|>> jvm_parser.read_class product.left) supers)]))
 
 (exception: #export (mismatched_super_parameters {name Text} {expected Nat} {actual Nat})
   (exception.report
@@ -2052,9 +2052,9 @@
                                               {actual (List (Type Parameter))})
   (exception.report
    ["Expected (amount)" (%.nat (list.size expected))]
-   ["Expected (parameters)" (exception.enumerate %.text expected)]
+   ["Expected (parameters)" (exception.listing %.text expected)]
    ["Actual (amount)" (%.nat (list.size actual))]
-   ["Actual (parameters)" (exception.enumerate ..signature actual)]))
+   ["Actual (parameters)" (exception.listing ..signature actual)]))
 
 (def: (super_aliasing class_loader class)
   (-> java/lang/ClassLoader (Type Class) (Operation Aliasing))
@@ -2141,7 +2141,7 @@
                                         super_interfaces))
          selfT (///.lift (do meta.monad
                            [where meta.current_module_name
-                            id meta.count]
+                            id meta.seed]
                            (in (inheritance_relationship_type (#.Primitive (..anonymous_class_name where id) (list))
                                                               super_classT
                                                               super_interfaceT+))))
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/analysis/lux.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/analysis/lux.lux
index 906b54e23..470078b0f 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/analysis/lux.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/analysis/lux.lux
@@ -90,8 +90,8 @@
    (do <>.monad
      [raw <code>.text]
      (case (text.size raw)
-       1 (in (|> raw (text.nth 0) maybe.assume))
-       _ (<>.failure (exception.construct ..char_text_must_be_size_1 [raw])))))
+       1 (in (|> raw (text.char 0) maybe.assume))
+       _ (<>.failure (exception.error ..char_text_must_be_size_1 [raw])))))
 
  (def: lux::syntax_char_case!
    (..custom
@@ -164,9 +164,9 @@
     (case args
       (^ (list typeC valueC))
       (do {! ////.monad}
-        [count (///.lift meta.count)
+        [seed (///.lift meta.seed)
          actualT (\ ! map (|>> (:as Type))
-                    (eval archive count Type typeC))
+                    (eval archive seed Type typeC))
          _ (typeA.infer actualT)]
         (typeA.with_type actualT
           (analyse archive valueC)))
@@ -180,9 +180,9 @@
     (case args
       (^ (list typeC valueC))
       (do {! ////.monad}
-        [count (///.lift meta.count)
+        [seed (///.lift meta.seed)
          actualT (\ ! map (|>> (:as Type))
-                    (eval archive count Type typeC))
+                    (eval archive seed Type typeC))
          _ (typeA.infer actualT)
          [valueT valueA] (typeA.with_inference
                            (analyse archive valueC))]
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/generation/jvm/host.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/generation/jvm/host.lux
index 2c78f5988..8f61e7ea8 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/generation/jvm/host.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/generation/jvm/host.lux
@@ -345,7 +345,7 @@
         (in elementJT)
 
         #.None
-        (<>.failure (exception.construct ..not_an_object_array arrayJT)))
+        (<>.failure (exception.error ..not_an_object_array arrayJT)))
       
       #.None
       (undefined))))
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/generation/lua/host.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/generation/lua/host.lux
index a66a198c7..b728760c0 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/generation/lua/host.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/generation/lua/host.lux
@@ -43,7 +43,7 @@
 
 (def: (array::read [indexG arrayG])
   (Binary Expression)
-  (_.nth (_.+ (_.int +1) indexG) arrayG))
+  (_.item (_.+ (_.int +1) indexG) arrayG))
 
 (def: (array::write [indexG valueG arrayG])
   (Trinary Expression)
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/generation/php/host.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/generation/php/host.lux
index 39ddd3df9..f7a42c5d2 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/generation/php/host.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/generation/php/host.lux
@@ -39,7 +39,7 @@
 
 (def: (array::read [indexG arrayG])
   (Binary Expression)
-  (_.nth indexG arrayG))
+  (_.item indexG arrayG))
 
 (def: (array::write [indexG valueG arrayG])
   (Trinary Expression)
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/generation/python/host.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/generation/python/host.lux
index 56393387f..57e53f579 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/generation/python/host.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/generation/python/host.lux
@@ -42,7 +42,7 @@
 
 (def: (array::read [indexG arrayG])
   (Binary (Expression Any))
-  (_.nth indexG arrayG))
+  (_.item indexG arrayG))
 
 (def: (array::write [indexG valueG arrayG])
   (Trinary (Expression Any))
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/generation/ruby/host.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/generation/ruby/host.lux
index 9e6df81c7..cb2e4d28b 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/generation/ruby/host.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/generation/ruby/host.lux
@@ -43,7 +43,7 @@
 
 (def: (array::read [indexG arrayG])
   (Binary Expression)
-  (_.nth indexG arrayG))
+  (_.item indexG arrayG))
 
 (def: (array::write [indexG valueG arrayG])
   (Trinary Expression)
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/common_lisp/runtime.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/common_lisp/runtime.lux
index 6b390352b..b69836192 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/common_lisp/runtime.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/common_lisp/runtime.lux
@@ -90,7 +90,7 @@
 (syntax: #export (with_vars {vars (<code>.tuple (<>.some <code>.local_identifier))}
                    body)
   (do {! meta.monad}
-    [ids (monad.seq ! (list.repeat (list.size vars) meta.count))]
+    [ids (monad.seq ! (list.repeat (list.size vars) meta.seed))]
     (in (list (` (let [(~+ (|> vars
                                (list.zipped/2 ids)
                                (list\map (function (_ [id var])
@@ -104,7 +104,7 @@
                                                             (<>.some <code>.local_identifier))))}
            code)
   (do meta.monad
-    [runtime_id meta.count]
+    [runtime_id meta.seed]
     (macro.with_gensyms [g!_]
       (let [runtime (code.local_identifier (///reference.artifact [..module_id runtime_id]))
             runtime_name (` (_.var (~ (code.text (%.code runtime)))))]
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/js/runtime.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/js/runtime.lux
index 5ac8a93ec..d351cd6ac 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/js/runtime.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/js/runtime.lux
@@ -88,7 +88,7 @@
 (syntax: #export (with_vars {vars (<code>.tuple (<>.some <code>.local_identifier))}
                    body)
   (do {! meta.monad}
-    [ids (monad.seq ! (list.repeat (list.size vars) meta.count))]
+    [ids (monad.seq ! (list.repeat (list.size vars) meta.seed))]
     (in (list (` (let [(~+ (|> vars
                                (list.zipped/2 ids)
                                (list\map (function (_ [id var])
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/lua/case.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/lua/case.lux
index 0e1b681c4..6d1fda16c 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/lua/case.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/lua/case.lux
@@ -113,7 +113,7 @@
 
 (def: peek
   Expression
-  (_.nth (_.length @cursor) @cursor))
+  (_.item (_.length @cursor) @cursor))
 
 (def: save!
   Statement
@@ -214,7 +214,7 @@
        [/////synthesis.side/right /////synthesis.simple_right_side ..right_choice])
 
       (^ (/////synthesis.member/left 0))
-      (///////phase\in (|> ..peek (_.nth (_.int +1)) ..push!))
+      (///////phase\in (|> ..peek (_.item (_.int +1)) ..push!))
       
       (^template [<pm> <getter>]
         [(^ (<pm> lefts))
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/lua/function.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/lua/function.lux
index 9affe12f6..28c33a86a 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/lua/function.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/lua/function.lux
@@ -82,7 +82,7 @@
            initialize! (list\fold (.function (_ post pre!)
                                     ($_ _.then
                                         pre!
-                                        (_.local/1 (..input post) (_.nth (|> post inc .int _.int) @curried))))
+                                        (_.local/1 (..input post) (_.item (|> post inc .int _.int) @curried))))
                                   initialize_self!
                                   (list.indices arity))
            pack (|>> (list) _.array)
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/lua/runtime.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/lua/runtime.lux
index 7d92f48d3..935caf949 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/lua/runtime.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/lua/runtime.lux
@@ -105,7 +105,7 @@
 (syntax: #export (with_vars {vars (<code>.tuple (<>.some <code>.local_identifier))}
                    body)
   (do {! meta.monad}
-    [ids (monad.seq ! (list.repeat (list.size vars) meta.count))]
+    [ids (monad.seq ! (list.repeat (list.size vars) meta.seed))]
     (in (list (` (let [(~+ (|> vars
                                (list.zipped/2 ids)
                                (list\map (function (_ [id var])
@@ -122,7 +122,7 @@
                                                             (<>.some <code>.local_identifier))))}
            code)
   (do meta.monad
-    [runtime_id meta.count]
+    [runtime_id meta.seed]
     (macro.with_gensyms [g!_]
       (let [runtime (code.local_identifier (///reference.artifact [..module_id runtime_id]))
             runtime_name (` (_.var (~ (code.text (%.code runtime)))))]
@@ -158,16 +158,16 @@
                                             (_.function (~ g!_) (list (~+ inputsC))
                                               (~ code))))))))))))))))
 
-(def: (nth index table)
+(def: (item index table)
   (-> Expression Expression Location)
-  (_.nth (_.+ (_.int +1) index) table))
+  (_.item (_.+ (_.int +1) index) table))
 
 (def: last_index
   (|>> _.length (_.- (_.int +1))))
 
 (with_expansions [<recur> (as_is ($_ _.then
                                      (_.set (list lefts) (_.- last_index_right lefts))
-                                     (_.set (list tuple) (..nth last_index_right tuple))))]
+                                     (_.set (list tuple) (..item last_index_right tuple))))]
   (runtime: (tuple//left lefts tuple)
     (with_vars [last_index_right]
       (<| (_.while (_.bool true))
@@ -175,7 +175,7 @@
               (_.local/1 last_index_right (..last_index tuple))
               (_.if (_.> lefts last_index_right)
                 ## No need for recursion
-                (_.return (..nth lefts tuple))
+                (_.return (..item lefts tuple))
                 ## Needs recursion
                 <recur>)))))
 
@@ -186,7 +186,7 @@
               (_.local/1 last_index_right (..last_index tuple))
               (_.local/1 right_index (_.+ (_.int +1) lefts))
               (_.cond (list [(_.= last_index_right right_index)
-                             (_.return (..nth right_index tuple))]
+                             (_.return (..item right_index tuple))]
                             [(_.> last_index_right right_index)
                              ## Needs recursion.
                              <recur>])
@@ -246,7 +246,7 @@
     ($_ _.then
         (_.let (list tail) ..none)
         (<| (_.for_step idx (_.length raw) (_.int +1) (_.int -1))
-            (_.set (list tail) (..some (_.array (list (_.nth idx raw)
+            (_.set (list tail) (..some (_.array (list (_.item idx raw)
                                                       tail)))))
         (_.return tail))))
 
@@ -399,7 +399,7 @@
 
 (runtime: (array//write idx value array)
   ($_ _.then
-      (_.set (list (..nth idx array)) value)
+      (_.set (list (..item idx array)) value)
       (_.return array)))
 
 (def: runtime//array
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/php/case.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/php/case.lux
index 5eb23e1a9..549d19954 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/php/case.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/php/case.lux
@@ -50,7 +50,7 @@
     (in (|> bodyG
             (list (_.set (..register register) valueG))
             _.array/*
-            (_.nth (_.int +1))))))
+            (_.item (_.int +1))))))
 
 (def: #export (let! statement expression archive [valueS register bodyS])
   (Generator! [Synthesis Register Synthesis])
@@ -112,8 +112,8 @@
 
 (def: peek
   Expression
-  (_.nth (|> @cursor _.count/1 (_.- (_.int +1)))
-         @cursor))
+  (_.item (|> @cursor _.count/1 (_.- (_.int +1)))
+          @cursor))
 
 (def: save!
   Statement
@@ -216,7 +216,7 @@
        [/////synthesis.side/right /////synthesis.simple_right_side ..right_choice])
 
       (^ (/////synthesis.member/left 0))
-      (///////phase\in (|> ..peek (_.nth (_.int +0)) ..push!))
+      (///////phase\in (|> ..peek (_.item (_.int +0)) ..push!))
       
       (^template [<pm> <getter>]
         [(^ (<pm> lefts))
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/php/extension/common.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/php/extension/common.lux
index 08a124e2c..f3ad84b3d 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/php/extension/common.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/php/extension/common.lux
@@ -86,7 +86,7 @@
           (bundle.install "index" (trinary text//index))
           (bundle.install "size" (unary _.strlen/1))
           (bundle.install "char" (binary (function (text//char [text idx])
-                                           (|> text (_.nth idx) _.ord/1))))
+                                           (|> text (_.item idx) _.ord/1))))
           (bundle.install "clip" (trinary (function (text//clip [from to text])
                                             (_.substr/3 [text from (_.- from to)]))))
           )))
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/php/function.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/php/function.lux
index 9f02325d3..6318a9d88 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/php/function.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/php/function.lux
@@ -87,7 +87,7 @@
            initialize! (list\fold (.function (_ post pre!)
                                     ($_ _.then
                                         pre!
-                                        (_.set! (..input post) (_.nth (|> post .int _.int) @curried))))
+                                        (_.set! (..input post) (_.item (|> post .int _.int) @curried))))
                                   initialize_self!
                                   (list.indices arity))]
      #let [[definition instantiation] (..with_closure closureG+ @selfG @selfL
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/php/loop.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/php/loop.lux
index 630e222e5..0c3c94f1f 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/php/loop.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/php/loop.lux
@@ -118,5 +118,5 @@
                      (|> argsO+
                          list.enumeration
                          (list\map (function (_ [idx _])
-                                     (_.nth (_.int (.int idx)) @temp))))
+                                     (_.item (_.int (.int idx)) @temp))))
                      (_.go_to @scope))))))
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/php/runtime.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/php/runtime.lux
index 6c08b4ed0..a18335967 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/php/runtime.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/php/runtime.lux
@@ -73,7 +73,7 @@
 (syntax: #export (with_vars {vars (<code>.tuple (<>.some <code>.local_identifier))}
                    body)
   (do {! meta.monad}
-    [ids (monad.seq ! (list.repeat (list.size vars) meta.count))]
+    [ids (monad.seq ! (list.repeat (list.size vars) meta.seed))]
     (in (list (` (let [(~+ (|> vars
                                (list.zipped/2 ids)
                                (list\map (function (_ [id var])
@@ -90,7 +90,7 @@
                                                             (<>.some <code>.local_identifier))))}
            code)
   (do meta.monad
-    [runtime_id meta.count]
+    [runtime_id meta.seed]
     (macro.with_gensyms [g!_]
       (let [runtime (code.local_identifier (///reference.artifact [..module_id runtime_id]))
             runtime_name (` (_.constant (~ (code.text (%.code runtime)))))]
@@ -149,7 +149,7 @@
   "_lux_size")
 
 (def: tuple_size
-  (_.nth (_.string ..tuple_size_field)))
+  (_.item (_.string ..tuple_size_field)))
 
 (def: jphp?
   (_.=== (_.string "5.6.99") (_.phpversion/0 [])))
@@ -162,7 +162,7 @@
 
 (runtime: (array//write idx value array)
   ($_ _.then
-      (_.set! (_.nth idx array) value)
+      (_.set! (_.item idx array) value)
       (_.return array)))
 
 (def: runtime//array
@@ -180,7 +180,7 @@
 
 (with_expansions [<recur> (as_is ($_ _.then
                                      (_.set! lefts (_.- last_index_right lefts))
-                                     (_.set! tuple (_.nth last_index_right tuple))))]
+                                     (_.set! tuple (_.item last_index_right tuple))))]
   (runtime: (tuple//make size values)
     (_.if ..jphp?
       ($_ _.then
@@ -202,7 +202,7 @@
                 (_.set! last_index_right (..normal_last_index tuple)))
               (_.if (_.> lefts last_index_right)
                 ## No need for recursion
-                (_.return (_.nth lefts tuple))
+                (_.return (_.item lefts tuple))
                 ## Needs recursion
                 <recur>)))))
 
@@ -215,7 +215,7 @@
           (_.set! output (_.array/* (list)))
           (<| (_.while (|> index (_.+ offset) (_.< size)))
               ($_ _.then
-                  (_.set! (_.nth index output) (_.nth (_.+ offset index) input))
+                  (_.set! (_.item index output) (_.item (_.+ offset index) input))
                   (_.set! index (_.+ (_.int +1) index))
                   ))
           (_.return (..tuple//make (_.- offset size) output))
@@ -230,7 +230,7 @@
                 (_.set! last_index_right (..normal_last_index tuple)))
               (_.set! right_index (_.+ (_.int +1) lefts))
               (_.cond (list [(_.=== last_index_right right_index)
-                             (_.return (_.nth right_index tuple))]
+                             (_.return (_.item right_index tuple))]
                             [(_.> last_index_right right_index)
                              ## Needs recursion.
                              <recur>])
@@ -274,12 +274,12 @@
 
 (runtime: (sum//get sum wantsLast wantedTag)
   (let [no_match! (_.return _.null)
-        sum_tag (_.nth (_.string ..variant_tag_field) sum)
-        ## sum_tag (_.nth (_.int +0) sum)
-        sum_flag (_.nth (_.string ..variant_flag_field) sum)
-        ## sum_flag (_.nth (_.int +1) sum)
-        sum_value (_.nth (_.string ..variant_value_field) sum)
-        ## sum_value (_.nth (_.int +2) sum)
+        sum_tag (_.item (_.string ..variant_tag_field) sum)
+        ## sum_tag (_.item (_.int +0) sum)
+        sum_flag (_.item (_.string ..variant_flag_field) sum)
+        ## sum_flag (_.item (_.int +1) sum)
+        sum_value (_.item (_.string ..variant_value_field) sum)
+        ## sum_value (_.item (_.int +2) sum)
         is_last? (_.=== ..unit sum_flag)
         test_recursion! (_.if is_last?
                           ## Must recurse.
@@ -540,7 +540,7 @@
                     _.iconv/3
                     [(_.string "V")]
                     _.unpack/2
-                    (_.nth (_.int +1)))))
+                    (_.item (_.int +1)))))
     (_.throw (_.new (_.constant "Exception") (list (_.string "[Lux Error] Cannot get char from text."))))))
 
 (def: runtime//text
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/python/case.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/python/case.lux
index cdfaf74fe..fa1a42e49 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/python/case.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/python/case.lux
@@ -117,7 +117,7 @@
 
 (def: peek
   (Expression Any)
-  (_.nth (_.int -1) @cursor))
+  (_.item (_.int -1) @cursor))
 
 (def: save!
   (Statement Any)
@@ -246,7 +246,7 @@
            [/////synthesis.side/right /////synthesis.simple_right_side ..right_choice])
 
           (^ (/////synthesis.member/left 0))
-          (///////phase\in (|> ..peek (_.nth (_.int +0)) ..push!))
+          (///////phase\in (|> ..peek (_.item (_.int +0)) ..push!))
           
           (^template [<pm> <getter>]
             [(^ (<pm> lefts))
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/python/function.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/python/function.lux
index 58d814dcc..fd225dfe4 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/python/function.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/python/function.lux
@@ -83,7 +83,7 @@
            initialize! (list\fold (.function (_ post pre!)
                                     ($_ _.then
                                         pre!
-                                        (_.set (list (..input post)) (_.nth (|> post .int _.int) @curried))))
+                                        (_.set (list (..input post)) (_.item (|> post .int _.int) @curried))))
                                   initialize_self!
                                   (list.indices arity))]]
     (with_closure function_artifact @self environment
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/python/loop.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/python/loop.lux
index 830154cbd..37296dd7c 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/python/loop.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/python/loop.lux
@@ -115,7 +115,7 @@
      #let [re_binds (|> argsO+
                         list.enumeration
                         (list\map (function (_ [idx _])
-                                    (_.nth (_.int (.int idx)) @temp))))]]
+                                    (_.item (_.int (.int idx)) @temp))))]]
     (in ($_ _.then
             (_.set (list @temp) (_.list argsO+))
             (..setup offset re_binds
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/python/runtime.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/python/runtime.lux
index 44ea19376..b653d67b7 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/python/runtime.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/python/runtime.lux
@@ -112,7 +112,7 @@
 (syntax: #export (with_vars {vars (<code>.tuple (<>.some <code>.local_identifier))}
                    body)
   (do {! meta.monad}
-    [ids (monad.seq ! (list.repeat (list.size vars) meta.count))]
+    [ids (monad.seq ! (list.repeat (list.size vars) meta.seed))]
     (in (list (` (let [(~+ (|> vars
                                (list.zipped/2 ids)
                                (list\map (function (_ [id var])
@@ -209,7 +209,7 @@
 
 (with_expansions [<recur> (as_is ($_ _.then
                                      (_.set (list lefts) (_.- last_index_right lefts))
-                                     (_.set (list tuple) (_.nth last_index_right tuple))))]
+                                     (_.set (list tuple) (_.item last_index_right tuple))))]
   (runtime: (tuple::left lefts tuple)
     (with_vars [last_index_right]
       (_.while (_.bool true)
@@ -217,7 +217,7 @@
                    (_.set (list last_index_right) (..last_index tuple))
                    (_.if (_.> lefts last_index_right)
                      ## No need for recursion
-                     (_.return (_.nth lefts tuple))
+                     (_.return (_.item lefts tuple))
                      ## Needs recursion
                      <recur>))
                #.None)))
@@ -229,7 +229,7 @@
                    (_.set (list last_index_right) (..last_index tuple))
                    (_.set (list right_index) (_.+ (_.int +1) lefts))
                    (_.cond (list [(_.= last_index_right right_index)
-                                  (_.return (_.nth right_index tuple))]
+                                  (_.return (_.item right_index tuple))]
                                  [(_.> last_index_right right_index)
                                   ## Needs recursion.
                                   <recur>])
@@ -238,9 +238,9 @@
 
 (runtime: (sum::get sum wantsLast wantedTag)
   (let [no_match! (_.return _.none)
-        sum_tag (_.nth (_.int +0) sum)
-        sum_flag (_.nth (_.int +1) sum)
-        sum_value (_.nth (_.int +2) sum)
+        sum_tag (_.item (_.int +0) sum)
+        sum_flag (_.item (_.int +1) sum)
+        sum_value (_.item (_.int +2) sum)
         is_last? (_.= ..unit sum_flag)
         test_recursion! (_.if is_last?
                           ## Must recurse.
@@ -421,7 +421,7 @@
 
 (runtime: (array::write idx value array)
   ($_ _.then
-      (_.set (list (_.nth idx array)) value)
+      (_.set (list (_.item idx array)) value)
       (_.return array)))
 
 (def: runtime::array
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/r/case.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/r/case.lux
index 8ef713643..dcaf7f395 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/r/case.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/r/case.lux
@@ -90,11 +90,11 @@
 
 (def: (push! value var)
   (-> Expression SVar Expression)
-  (_.set_nth! (next var) value var))
+  (_.set_item! (next var) value var))
 
 (def: (pop! var)
   (-> SVar Expression)
-  (_.set_nth! (top var) _.null var))
+  (_.set_item! (top var) _.null var))
 
 (def: (push_cursor! value)
   (-> Expression Expression)
@@ -107,11 +107,11 @@
 
 (def: restore_cursor!
   Expression
-  (_.set! $cursor (_.nth (top $savepoint) $savepoint)))
+  (_.set! $cursor (_.item (top $savepoint) $savepoint)))
 
 (def: peek
   Expression
-  (|> $cursor (_.nth (top $cursor))))
+  (|> $cursor (_.item (top $cursor))))
 
 (def: pop_cursor!
   Expression
@@ -190,7 +190,7 @@
        [/////synthesis.side/right true  inc])
 
       (^ (/////synthesis.member/left 0))
-      (///////phase\in (_.nth (_.int +1) ..peek))
+      (///////phase\in (_.item (_.int +1) ..peek))
 
       (^template [<pm> <getter>]
         [(^ (<pm> lefts))
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/r/function.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/r/function.lux
index a6497d206..850f99475 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/r/function.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/r/function.lux
@@ -69,7 +69,7 @@
 (def: (input_declaration register)
   (-> Register Expression)
   (_.set! (|> register inc //case.register)
-          (|> $curried (_.nth (|> register inc .int _.int)))))
+          (|> $curried (_.item (|> register inc .int _.int)))))
 
 (def: #export (function expression archive [environment arity bodyS])
   (Generator (Abstraction Synthesis))
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/r/runtime.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/r/runtime.lux
index 0dcaf6ac8..f71070979 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/r/runtime.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/r/runtime.lux
@@ -79,7 +79,7 @@
 (syntax: #export (with_vars {vars (<code>.tuple (<>.some <code>.local_identifier))}
                    body)
   (do {! meta.monad}
-    [ids (monad.seq ! (list.repeat (list.size vars) meta.count))]
+    [ids (monad.seq ! (list.repeat (list.size vars) meta.seed))]
     (in (list (` (let [(~+ (|> vars
                                (list.zipped/2 ids)
                                (list\map (function (_ [id var])
@@ -93,7 +93,7 @@
                                                             (<>.some <code>.local_identifier))))}
            code)
   (do meta.monad
-    [runtime_id meta.count]
+    [runtime_id meta.seed]
     (macro.with_gensyms [g!_]
       (let [runtime (code.local_identifier (///reference.artifact [..module_id runtime_id]))
             runtime_name (` (_.var (~ (code.text (%.code runtime)))))]
@@ -180,14 +180,14 @@
 (runtime: (i64::unsigned_low input)
   (with_vars [low]
     ($_ _.then
-        (_.set! low (|> input (_.nth (_.string ..i64_low_field))))
+        (_.set! low (|> input (_.item (_.string ..i64_low_field))))
         (_.if (|> low (_.>= (_.int +0)))
           low
           (|> low (_.+ f2^32))))))
 
 (runtime: (i64::to_float input)
   (let [high (|> input
-                 (_.nth (_.string ..i64_high_field))
+                 (_.item (_.string ..i64_high_field))
                  high_shift)
         low (|> input
                 i64::unsigned_low)]
@@ -227,8 +227,8 @@
   [i64::max i\top]
   )
 
-(def: #export i64_high (_.nth (_.string ..i64_high_field)))
-(def: #export i64_low (_.nth (_.string ..i64_low_field)))
+(def: #export i64_high (_.item (_.string ..i64_high_field)))
+(def: #export i64_low (_.item (_.string ..i64_low_field)))
 
 (runtime: (i64::not input)
   (i64::new (|> input i64_high _.bit_not)
@@ -524,8 +524,8 @@
                (..right value))
            #.None
            (#.Some (_.function (list error)
-                     (..left (_.nth (_.string "message")
-                                    error))))
+                     (..left (_.item (_.string "message")
+                                     error))))
            #.None)))
 
 (runtime: (lux::program_args program_args)
@@ -565,11 +565,11 @@
 
 (def: (product_element product index)
   (-> Expression Expression Expression)
-  (|> product (_.nth (|> index (_.+ (_.int +1))))))
+  (|> product (_.item (|> index (_.+ (_.int +1))))))
 
 (def: (product_tail product)
   (-> SVar Expression)
-  (|> product (_.nth (_.length product))))
+  (|> product (_.item (_.length product))))
 
 (def: (updated_index min_length product)
   (-> Expression Expression Expression)
@@ -602,9 +602,9 @@
 
 (runtime: (sum::get sum wants_last? wanted_tag)
   (let [no_match _.null
-        sum_tag (|> sum (_.nth (_.string ..variant_tag_field)))
-        sum_flag (|> sum (_.nth (_.string ..variant_flag_field)))
-        sum_value (|> sum (_.nth (_.string ..variant_value_field)))
+        sum_tag (|> sum (_.item (_.string ..variant_tag_field)))
+        sum_flag (|> sum (_.item (_.string ..variant_flag_field)))
+        sum_value (|> sum (_.item (_.string ..variant_value_field)))
         is_last? (|> sum_flag (_.= (_.string "")))
         test_recursion (_.if is_last?
                          ## Must recurse.
@@ -754,7 +754,7 @@
                                                                    subject)))
                                           (list ["fixed" (_.bool #1)])
                                           (_.var "regexpr"))
-                              (_.nth (_.int +1))))
+                              (_.item (_.int +1))))
               (_.if (|> idx (_.= (_.int -1)))
                 ..none
                 (..some (i64::of_float (|> idx (_.+ startF))))))
@@ -799,16 +799,16 @@
   (with_vars [output]
     ($_ _.then
         (_.set! output (_.list (list)))
-        (_.set_nth! (|> size (_.+ (_.int +1)))
-                    _.null
-                    output)
+        (_.set_item! (|> size (_.+ (_.int +1)))
+                     _.null
+                     output)
         output)))
 
 (runtime: (array::get array idx)
   (with_vars [temp]
     (<| (check_index_out_of_bounds array idx)
         ($_ _.then
-            (_.set! temp (|> array (_.nth (_.+ (_.int +1) idx))))
+            (_.set! temp (|> array (_.item (_.+ (_.int +1) idx))))
             (_.if (|> temp (_.= _.null))
               ..none
               (..some temp))))))
@@ -816,7 +816,7 @@
 (runtime: (array::put array idx value)
   (<| (check_index_out_of_bounds array idx)
       ($_ _.then
-          (_.set_nth! (_.+ (_.int +1) idx) value array)
+          (_.set_item! (_.+ (_.int +1) idx) value array)
           array)))
 
 (def: runtime::array
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/ruby/case.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/ruby/case.lux
index d1bbfae39..18185171c 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/ruby/case.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/ruby/case.lux
@@ -119,7 +119,7 @@
 
 (def: peek
   Expression
-  (_.nth (_.int -1) @cursor))
+  (_.item (_.int -1) @cursor))
 
 (def: save!
   Statement
@@ -287,7 +287,7 @@
            [/////synthesis.side/right /////synthesis.simple_right_side ..right_choice])
 
           (^ (/////synthesis.member/left 0))
-          (///////phase\in (|> ..peek (_.nth (_.int +0)) ..push!))
+          (///////phase\in (|> ..peek (_.item (_.int +0)) ..push!))
           
           (^template [<pm> <getter>]
             [(^ (<pm> lefts))
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/ruby/function.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/ruby/function.lux
index 8c849da68..e7e831a77 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/ruby/function.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/ruby/function.lux
@@ -80,7 +80,7 @@
            initialize! (list\fold (.function (_ post pre!)
                                     ($_ _.then
                                         pre!
-                                        (_.set (list (..input post)) (_.nth (|> post .int _.int) @curried))))
+                                        (_.set (list (..input post)) (_.item (|> post .int _.int) @curried))))
                                   initialize_self!
                                   (list.indices arity))
            [declaration instatiation] (with_closure closureO+ function_name
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/ruby/loop.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/ruby/loop.lux
index d021df198..5c255fcc9 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/ruby/loop.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/ruby/loop.lux
@@ -89,7 +89,7 @@
      #let [re_binds (|> argsO+
                         list.enumeration
                         (list\map (function (_ [idx _])
-                                    (_.nth (_.int (.int idx)) @temp))))]]
+                                    (_.item (_.int (.int idx)) @temp))))]]
     (in ($_ _.then
             (_.set (list @temp) (_.array argsO+))
             (..setup offset re_binds
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/ruby/runtime.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/ruby/runtime.lux
index 1ab1ab616..989fdf220 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/ruby/runtime.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/ruby/runtime.lux
@@ -74,7 +74,7 @@
 (syntax: #export (with_vars {vars (<code>.tuple (<>.some <code>.local_identifier))}
                    body)
   (do {! meta.monad}
-    [ids (monad.seq ! (list.repeat (list.size vars) meta.count))]
+    [ids (monad.seq ! (list.repeat (list.size vars) meta.seed))]
     (in (list (` (let [(~+ (|> vars
                                (list.zipped/2 ids)
                                (list\map (function (_ [id var])
@@ -91,7 +91,7 @@
                                                             (<>.some <code>.local_identifier))))}
            code)
   (do meta.monad
-    [runtime_id meta.count]
+    [runtime_id meta.seed]
     (macro.with_gensyms [g!_]
       (let [runtime (code.local_identifier (///reference.artifact [..module_id runtime_id]))
             runtime_name (` (_.local (~ (code.text (%.code runtime)))))]
@@ -132,7 +132,7 @@
 
 (with_expansions [<recur> (as_is ($_ _.then
                                      (_.set (list lefts) (_.- last_index_right lefts))
-                                     (_.set (list tuple) (_.nth last_index_right tuple))))]
+                                     (_.set (list tuple) (_.item last_index_right tuple))))]
   (runtime: (tuple//left lefts tuple)
     (with_vars [last_index_right]
       (<| (_.while (_.bool true))
@@ -140,7 +140,7 @@
               (_.set (list last_index_right) (..last_index tuple))
               (_.if (_.> lefts last_index_right)
                 ## No need for recursion
-                (_.return (_.nth lefts tuple))
+                (_.return (_.item lefts tuple))
                 ## Needs recursion
                 <recur>)))))
 
@@ -151,7 +151,7 @@
               (_.set (list last_index_right) (..last_index tuple))
               (_.set (list right_index) (_.+ (_.int +1) lefts))
               (_.cond (list [(_.= last_index_right right_index)
-                             (_.return (_.nth right_index tuple))]
+                             (_.return (_.item right_index tuple))]
                             [(_.> last_index_right right_index)
                              ## Needs recursion.
                              <recur>])
@@ -189,9 +189,9 @@
 
 (runtime: (sum//get sum wantsLast wantedTag)
   (let [no_match! (_.return _.nil)
-        sum_tag (_.nth (_.string ..variant_tag_field) sum)
-        sum_flag (_.nth (_.string ..variant_flag_field) sum)
-        sum_value (_.nth (_.string ..variant_value_field) sum)
+        sum_tag (_.item (_.string ..variant_tag_field) sum)
+        sum_flag (_.item (_.string ..variant_flag_field) sum)
+        sum_value (_.item (_.string ..variant_value_field) sum)
         is_last? (_.= ..unit sum_flag)
         test_recursion! (_.if is_last?
                           ## Must recurse.
@@ -369,7 +369,7 @@
 
 (runtime: (array//write idx value array)
   ($_ _.then
-      (_.set (list (_.nth idx array)) value)
+      (_.set (list (_.item idx array)) value)
       (_.return array)))
 
 (def: runtime//array
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/scheme/runtime.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/scheme/runtime.lux
index 2e5c8d495..72ec2ef27 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/scheme/runtime.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/generation/scheme/runtime.lux
@@ -61,7 +61,7 @@
 (syntax: #export (with_vars {vars (<code>.tuple (<>.some <code>.local_identifier))}
                    body)
   (do {! meta.monad}
-    [ids (monad.seq ! (list.repeat (list.size vars) meta.count))]
+    [ids (monad.seq ! (list.repeat (list.size vars) meta.seed))]
     (in (list (` (let [(~+ (|> vars
                                (list.zipped/2 ids)
                                (list\map (function (_ [id var])
@@ -75,7 +75,7 @@
                                                             (<>.some <code>.local_identifier))))}
            code)
   (do meta.monad
-    [runtime_id meta.count]
+    [runtime_id meta.seed]
     (macro.with_gensyms [g!_]
       (let [runtime (code.local_identifier (///reference.artifact [..module_id runtime_id]))
             runtime_name (` (_.var (~ (code.text (%.code runtime)))))]
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/synthesis/function.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/synthesis/function.lux
index 4dc984bae..b19403e90 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/synthesis/function.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/synthesis/function.lux
@@ -30,7 +30,7 @@
 (exception: #export (cannot_find_foreign_variable_in_environment {foreign Register} {environment (Environment Synthesis)})
   (exception.report
    ["Foreign" (%.nat foreign)]
-   ["Environment" (exception.enumerate /.%synthesis environment)]))
+   ["Environment" (exception.listing /.%synthesis environment)]))
 
 (def: arity_arguments
   (-> Arity (List Synthesis))
@@ -83,7 +83,7 @@
 
 (def: (find_foreign environment register)
   (-> (Environment Synthesis) Register (Operation Synthesis))
-  (case (list.nth register environment)
+  (case (list.item register environment)
     (#.Some aliased)
     (phase\in aliased)
 
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/synthesis/loop.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/synthesis/loop.lux
index f64693134..6e83a6a6a 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/synthesis/loop.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/synthesis/loop.lux
@@ -110,7 +110,7 @@
 
         (^ (reference.foreign register))
         (if true_loop?
-          (list.nth register scope_environment)
+          (list.item register scope_environment)
           (#.Some expr)))
 
       (^ (/.branch/case [input path]))
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/program.lux b/stdlib/source/library/lux/tool/compiler/language/lux/program.lux
index 16b59870b..be1eead63 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/program.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/program.lux
@@ -30,7 +30,7 @@
 
 (exception: #export (cannot_find_program {modules (List Module)})
   (exception.report
-   ["Modules" (exception.enumerate %.text modules)]))
+   ["Modules" (exception.listing %.text modules)]))
 
 (def: #export (context archive)
   (-> Archive (Try Context))
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/syntax.lux b/stdlib/source/library/lux/tool/compiler/language/lux/syntax.lux
index d6c43e896..4c930475b 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/syntax.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/syntax.lux
@@ -169,11 +169,11 @@
 
 (template: (!failure parser where offset source_code)
   (#.Left [[where offset source_code]
-           (exception.construct ..unrecognized_input [where (%.name (name_of parser)) source_code offset])]))
+           (exception.error ..unrecognized_input [where (%.name (name_of parser)) source_code offset])]))
 
 (template: (!end_of_file where offset source_code current_module)
   (#.Left [[where offset source_code]
-           (exception.construct ..end_of_file current_module)]))
+           (exception.error ..end_of_file current_module)]))
 
 (type: (Parser a)
   (-> Source (Either [Source Text] [Source a])))
@@ -263,7 +263,7 @@
 
     g!_
     (#.Left [[where offset source_code]
-             (exception.construct ..text_cannot_contain_new_lines content)])))
+             (exception.error ..text_cannot_contain_new_lines content)])))
 
 (def: (text_parser where offset source_code)
   (-> Location Offset Text (Either [Source Text] [Source Code]))
diff --git a/stdlib/source/library/lux/tool/compiler/meta/archive.lux b/stdlib/source/library/lux/tool/compiler/meta/archive.lux
index a45c7ad59..cd6b245ee 100644
--- a/stdlib/source/library/lux/tool/compiler/meta/archive.lux
+++ b/stdlib/source/library/lux/tool/compiler/meta/archive.lux
@@ -45,7 +45,7 @@
                                       {known_modules (List Module)})
   (exception.report
    ["Module" (%.text module)]
-   ["Known Modules" (exception.enumerate %.text known_modules)]))
+   ["Known Modules" (exception.listing %.text known_modules)]))
 
 (exception: #export (cannot_replace_document {module Module}
                                              {old (Document Any)}
diff --git a/stdlib/source/library/lux/tool/compiler/meta/archive/artifact.lux b/stdlib/source/library/lux/tool/compiler/meta/archive/artifact.lux
index 7feeac2a0..76266ad19 100644
--- a/stdlib/source/library/lux/tool/compiler/meta/archive/artifact.lux
+++ b/stdlib/source/library/lux/tool/compiler/meta/archive/artifact.lux
@@ -141,7 +141,7 @@
                            [5 #Directive <binary>.text]
                            [6 #Custom <binary>.text])
                           
-                          _ (<>.failure (exception.construct ..invalid_category [tag])))))]
+                          _ (<>.failure (exception.error ..invalid_category [tag])))))]
       (|> (<binary>.row/64 category)
           (\ <>.monad map (row\fold (function (_ artifact registry)
                                       (product.right
diff --git a/stdlib/source/library/lux/tool/compiler/meta/io/context.lux b/stdlib/source/library/lux/tool/compiler/meta/io/context.lux
index 8903ab503..e049ef8b5 100644
--- a/stdlib/source/library/lux/tool/compiler/meta/io/context.lux
+++ b/stdlib/source/library/lux/tool/compiler/meta/io/context.lux
@@ -138,7 +138,7 @@
 (type: #export Enumeration
   (Dictionary file.Path Binary))
 
-(def: (enumerate_context fs directory enumeration)
+(def: (context_listing fs directory enumeration)
   (-> (file.System Async) Context Enumeration (Async (Try Enumeration)))
   (do {! (try.with async.monad)}
     [enumeration (|> directory
@@ -153,17 +153,17 @@
                      (\ ! join))]
     (|> directory
         (\ fs sub_directories)
-        (\ ! map (monad.fold ! (enumerate_context fs) enumeration))
+        (\ ! map (monad.fold ! (context_listing fs) enumeration))
         (\ ! join))))
 
 (def: Action
   (type (All [a] (Async (Try a)))))
 
-(def: #export (enumerate fs contexts)
+(def: #export (listing fs contexts)
   (-> (file.System Async) (List Context) (Action Enumeration))
   (monad.fold (: (Monad Action)
                  (try.with async.monad))
-              (..enumerate_context fs)
+              (..context_listing fs)
               (: Enumeration
                  (dictionary.empty text.hash))
               contexts))
diff --git a/stdlib/source/library/lux/tool/compiler/phase.lux b/stdlib/source/library/lux/tool/compiler/phase.lux
index ed4def938..0a0db986e 100644
--- a/stdlib/source/library/lux/tool/compiler/phase.lux
+++ b/stdlib/source/library/lux/tool/compiler/phase.lux
@@ -74,7 +74,7 @@
 
 (def: #export (except exception parameters)
   (All [e] (-> (Exception e) e Operation))
-  (..failure (ex.construct exception parameters)))
+  (..failure (ex.error exception parameters)))
 
 (def: #export (lift error)
   (All [s a] (-> (Try a) (Operation s a)))