Fixes and improvements to JavaScript compilation.

18 files changed, 355 insertions, 227 deletions

diff --git a/commands.md b/commands.md
index edfd16b66..90235dee2 100644
--- a/commands.md
+++ b/commands.md
@@ -139,7 +139,7 @@ cd ~/lux/lux-jvm/ && java -jar target/program.jar repl --source ~/lux/stdlib/sou
 
 ```
 cd ~/lux/lux-jvm/ && time java -jar target/program.jar build --source ~/lux/stdlib/source --target ~/lux/stdlib/target --module test/lux
-cd ~/lux/stdlib/ && cd ~/lux/lux-jvm/ && time java -jar target/program.jar build --source ~/lux/stdlib/source --target ~/lux/stdlib/target --module test/lux
+cd ~/lux/stdlib/ && lein clean && cd ~/lux/lux-jvm/ && time java -jar target/program.jar build --source ~/lux/stdlib/source --target ~/lux/stdlib/target --module test/lux
 cd ~/lux/stdlib/ && cd ~/lux/lux-jvm/ && time java -jar target/program.jar build --source ~/lux/stdlib/source --library ~/lux/stdlib/target/library.tar --target ~/lux/stdlib/target --module test/lux
 cd ~/lux/lux-jvm/ && java -jar target/program.jar export --source ~/lux/stdlib/source --target ~/lux/stdlib/target
 
diff --git a/lux-js/source/program.lux b/lux-js/source/program.lux
index cebede1ab..3ecd9891b 100644
--- a/lux-js/source/program.lux
+++ b/lux-js/source/program.lux
@@ -13,6 +13,7 @@
     [concurrency
      ["." promise (#+ Promise)]]]
    [data
+    ["." product]
     ["." maybe]
     [number
      ["." i64]
@@ -32,6 +33,8 @@
    [tool
     [compiler
      [phase (#+ Operation Phase)]
+     [reference
+      [variable (#+ Register)]]
      [language
       [lux
        [program (#+ Program)]
@@ -145,7 +148,7 @@
        (|> value .nat runtime.low jvm-int)
 
        _
-       (error! (exception.construct unknown-member [member (:coerce java/lang/Object value)]))))
+       (error! (exception.construct ..unknown-member [member (:coerce java/lang/Object value)]))))
     ))
 
 (def: (::toString js-object)
@@ -228,7 +231,7 @@
          (|> value (array.read 2) maybe.assume js-object (:coerce java/lang/Object))
          
          _
-         (error! (exception.construct unknown-member [(:coerce Text member) (:coerce java/lang/Object value)])))
+         (error! (exception.construct ..unknown-member [(:coerce Text member) (:coerce java/lang/Object value)])))
        )
       (jdk/nashorn/api/scripting/AbstractJSObject
        [] (getSlot self {idx int}) java/lang/Object
@@ -239,7 +242,14 @@
            (:coerce java/lang/Object)))
       )))
 
-(exception: null-has-no-lux-representation)
+(exception: (null-has-no-lux-representation {code (Maybe _.Expression)})
+  (case code
+    (#.Some code)
+    (_.code code)
+
+    #.None
+    "???"))
+
 (exception: undefined-has-no-lux-representation)
 
 (exception: (unknown-kind-of-host-object {object java/lang/Object})
@@ -322,7 +332,7 @@
 (def: (lux-object js-object)
   (-> java/lang/Object (Try Any))
   (`` (<| (if (host.null? js-object)
-            (exception.throw ..null-has-no-lux-representation []))
+            (exception.throw ..null-has-no-lux-representation [#.None]))
           (case (host.check jdk/nashorn/internal/runtime/Undefined js-object)
             (#.Some _)
             (exception.throw ..undefined-has-no-lux-representation [])
@@ -391,7 +401,7 @@
 
 (def: (expander macro inputs lux)
   Expander
-  (case (ensure-macro macro)
+  (case (..ensure-macro macro)
     (#.Some macro)
     (case (call-macro inputs lux macro)
       (#try.Success output)
@@ -409,14 +419,13 @@
 (def: (evaluate! interpreter alias input)
   (-> javax/script/ScriptEngine Text _.Expression (Try Any))
   (do try.monad
-    [?output (javax/script/ScriptEngine::eval (_.code input) interpreter)
-     output (case ?output
-              (#.Some output)
-              (wrap output)
+    [?output (javax/script/ScriptEngine::eval (_.code input) interpreter)]
+    (case ?output
+      (#.Some output)
+      (..lux-object output)
 
-              #.None
-              (exception.throw ..null-has-no-lux-representation []))]
-    (..lux-object output)))
+      #.None
+      (exception.throw ..null-has-no-lux-representation [(#.Some input)]))))
 
 (def: (execute! interpreter alias input)
   (-> javax/script/ScriptEngine Text _.Statement (Try Any))
@@ -456,7 +465,7 @@
                 (..evaluate! interpreter "" (_.var (reference.artifact context))))))))))
 
 (def: platform
-  (IO (Platform _.Var _.Expression _.Statement))
+  (IO (Platform [Register Text] _.Expression _.Statement))
   (do io.monad
     [host ..host]
     (wrap {#platform.&file-system (file.async file.system)
diff --git a/lux-jvm/source/luxc/lang/translation/jvm.lux b/lux-jvm/source/luxc/lang/translation/jvm.lux
index 141e70184..cebd5e652 100644
--- a/lux-jvm/source/luxc/lang/translation/jvm.lux
+++ b/lux-jvm/source/luxc/lang/translation/jvm.lux
@@ -27,8 +27,9 @@
     [compiler
      [language
       [lux
+       ["." version]
        ["." generation]]]
-     ["." meta
+     [meta
       [io (#+ lux-context)]
       [archive
        [descriptor (#+ Module)]
@@ -99,7 +100,7 @@
 (def: #export (class-name [module-id artifact-id])
   (-> generation.Context Text)
   (format lux-context
-          ..class-path-separator (%.nat meta.version)
+          ..class-path-separator (%.nat version.version)
           ..class-path-separator (%.nat module-id)
           ..class-path-separator (%.nat artifact-id)))
 
diff --git a/stdlib/source/lux.lux b/stdlib/source/lux.lux
index d6fa1c40a..2409d3f39 100644
--- a/stdlib/source/lux.lux
+++ b/stdlib/source/lux.lux
@@ -2090,17 +2090,6 @@
            template}
           template))
 
-(def:''' (join-map f xs)
-         #Nil
-         (All [a b]
-           (-> (-> a ($' List b)) ($' List a) ($' List b)))
-         ({#Nil
-           #Nil
-
-           (#Cons [x xs'])
-           (list@compose (f x) (join-map f xs'))}
-          xs))
-
 (def:''' (every? p xs)
          #Nil
          (All [a]
@@ -2142,6 +2131,12 @@
            #1
            ("lux i64 =" reference sample)))
 
+(def:''' (list@join xs)
+         #Nil
+         (All [a]
+           (-> ($' List ($' List a)) ($' List a)))
+         (list@fold list@compose #Nil (list@reverse xs)))
+
 (macro:' #export (template tokens)
          (list [(tag$ ["lux" "doc"])
                 (text$ ($_ "lux text concat"
@@ -2158,7 +2153,8 @@
                    (if (every? (function' [size] ("lux i64 =" num-bindings size))
                                (list@map list@size data'))
                      (|> data'
-                         (join-map (compose apply (make-env bindings')))
+                         (list@map (compose apply (make-env bindings')))
+                         list@join
                          return)
                      (fail "Irregular arguments tuples for template.")))
 
@@ -2350,12 +2346,6 @@
                    #None     #0}
                   output))))
 
-(def:''' (list@join xs)
-         #Nil
-         (All [a]
-           (-> ($' List ($' List a)) ($' List a)))
-         (list@fold list@compose #Nil (list@reverse xs)))
-
 (def:''' (interpose sep xs)
          #Nil
          (All [a]
@@ -3253,38 +3243,6 @@
   (-> Text Text (Maybe Nat))
   ("lux text index" 0 part text))
 
-(def: (last-index-of' part part-size since text)
-  (-> Text Nat Nat Text (Maybe Nat))
-  (case ("lux text index" ("lux i64 +" part-size since) part text)
-    #None
-    (#Some since)
-
-    (#Some since')
-    (last-index-of' part part-size since' text)))
-
-(def: (last-index-of part text)
-  (-> Text Text (Maybe Nat))
-  (case ("lux text index" 0 part text)
-    (#Some since)
-    (last-index-of' part ("lux text size" part) since text)
-
-    #None
-    #None))
-
-(def: (clip/1 from text)
-  (-> Nat Text (Maybe Text))
-  (let [size ("lux text size" text)]
-    (if (n/<= size from)
-      (#.Some ("lux text clip" from size text))
-      #.None)))
-
-(def: (clip/2 from to text)
-  (-> Nat Nat Text (Maybe Text))
-  (if (and (n/<= to from)
-           (n/<= ("lux text size" text) to))
-    (#.Some ("lux text clip" from to text))
-    #.None))
-
 (def: #export (error! message)
   {#.doc (text$ ($_ "lux text concat"
                     "## Causes an error, with the given error message." ..new-line
@@ -3316,7 +3274,7 @@
 
 (def: (text@split-all-with splitter input)
   (-> Text Text (List Text))
-  (case (index-of splitter input)
+  (case (..index-of splitter input)
     #None
     (list input)
 
@@ -3766,13 +3724,13 @@
          (^ (list& [_ (#Form (list& [_ (#Tag ["" "only"])] defs))] tokens')))
     (do meta-monad
       [defs' (extract-defs defs)]
-      (return [(#Only defs') tokens']))
+      (wrap [(#Only defs') tokens']))
 
     (^or (^ (list& [_ (#Form (list& [_ (#Tag ["" "-"])] defs))] tokens'))
          (^ (list& [_ (#Form (list& [_ (#Tag ["" "exclude"])] defs))] tokens')))
     (do meta-monad
       [defs' (extract-defs defs)]
-      (return [(#Exclude defs') tokens']))
+      (wrap [(#Exclude defs') tokens']))
 
     (^or (^ (list& [_ (#Tag ["" "*"])] tokens'))
          (^ (list& [_ (#Tag ["" "all"])] tokens')))
@@ -4542,12 +4500,13 @@
                              (function (_ def)
                                (` ("lux def alias" (~ (local-identifier$ def)) (~ (identifier$ [module-name def]))))))
                           defs')
-           openings (join-map (: (-> Openings (List Code))
-                                 (function (_ [alias structs])
-                                   (list@map (function (_ name)
-                                               (` (open: (~ (text$ alias)) (~ (identifier$ [module-name name])))))
-                                             structs)))
-                              r-opens)]]
+           openings (|> r-opens
+                        (list@map (: (-> Openings (List Code))
+                                     (function (_ [alias structs])
+                                       (list@map (function (_ name)
+                                                   (` (open: (~ (text$ alias)) (~ (identifier$ [module-name name])))))
+                                                 structs))))
+                        list@join)]]
     (wrap (list@compose defs openings))
     ))
 
@@ -4856,7 +4815,8 @@
                    (let [apply (: (-> RepEnv (List Code))
                                   (function (_ env) (list@map (apply-template env) templates)))]
                      (|> data'
-                         (join-map (compose apply (make-env bindings')))
+                         (list@map (compose apply (make-env bindings')))
+                         list@join
                          wrap))
                    #None))))
       (#Some output)
diff --git a/stdlib/source/lux/control/concurrency/process.lux b/stdlib/source/lux/control/concurrency/process.lux
index 4d6cc8cb3..3b273753a 100644
--- a/stdlib/source/lux/control/concurrency/process.lux
+++ b/stdlib/source/lux/control/concurrency/process.lux
@@ -152,6 +152,6 @@
                         (do @
                           [_ (monad.map @ (get@ #action) ready)]
                           (wrap []))
-                        (error! (ex.construct cannot-continue-running-processes []))))
+                        (error! (ex.construct ..cannot-continue-running-processes []))))
                     ))))
             ))
diff --git a/stdlib/source/lux/data/binary.lux b/stdlib/source/lux/data/binary.lux
index 4d3eb962a..30c2bc193 100644
--- a/stdlib/source/lux/data/binary.lux
+++ b/stdlib/source/lux/data/binary.lux
@@ -12,7 +12,8 @@
     ["." maybe]
     [number
      ["." i64]
-     ["n" nat]]
+     ["n" nat]
+     ["f" frac]]
     [text
      ["%" format (#+ format)]]
     [collection
@@ -84,7 +85,7 @@
         (host.array-length binary)
 
         @.js
-        (.frac-to-nat (Uint8Array::length binary))}))
+        (f.nat (Uint8Array::length binary))}))
 
 (template: (!read idx binary)
   (for {@.old
@@ -98,7 +99,8 @@
             (: ..Binary)
             (:coerce (array.Array .Frac))
             ("js array read" idx)
-            .frac-to-nat)}))
+            f.nat
+            .i64)}))
 
 (template: (!write idx value binary)
   (for {@.old
@@ -111,7 +113,7 @@
         (|> binary
             (: ..Binary)
             (:coerce (array.Array .Frac))
-            ("js array write" idx (.nat-to-frac value))
+            ("js array write" idx (n.frac (.nat value)))
             (:coerce ..Binary))}))
 
 (def: #export size
@@ -127,7 +129,7 @@
         (|>> (host.array byte))
 
         @.js
-        (|>> .nat-to-frac [] ArrayBuffer::new Uint8Array::new)}))
+        (|>> n.frac [] ArrayBuffer::new Uint8Array::new)}))
 
 (def: #export (fold f init binary)
   (All [a] (-> (-> I64 a a) a Binary a))
diff --git a/stdlib/source/lux/macro/code.lux b/stdlib/source/lux/macro/code.lux
index 219bb76e4..8b868db58 100644
--- a/stdlib/source/lux/macro/code.lux
+++ b/stdlib/source/lux/macro/code.lux
@@ -10,9 +10,9 @@
      ["." int]
      ["." rev]
      ["." frac]]
-    ["." text ("#@." monoid)]
+    ["." text ("#@." monoid equivalence)]
     [collection
-     ["." list ("#@." functor)]]]])
+     ["." list ("#@." functor fold)]]]])
 
 ## (type: (Code' w)
 ##   (#.Bit Bit)
@@ -109,10 +109,13 @@
       [_ (<tag> members)]
       ($_ text@compose
           <open>
-          (|> members
-              (list@map to-text)
-              (list.interpose " ")
-              (text.join-with ""))
+          (list@fold (function (_ next prev)
+                       (let [next (to-text next)]
+                         (if (text@= "" prev)
+                           next
+                           ($_ text@compose prev " " next))))
+                     ""
+                     members)
           <close>))
     ([#.Form  "(" ")"]
      [#.Tuple "[" "]"])
@@ -120,11 +123,13 @@
     [_ (#.Record pairs)]
     ($_ text@compose
         "{"
-        (|> pairs
-            (list@map (function (_ [left right])
-                        ($_ text@compose (to-text left) " " (to-text right))))
-            (list.interpose " ")
-            (text.join-with ""))
+        (list@fold (function (_ [left right] prev)
+                     (let [next ($_ text@compose (to-text left) " " (to-text right))]
+                       (if (text@= "" prev)
+                         next
+                         ($_ text@compose prev " " next))))
+                   ""
+                   pairs)
         "}")
     ))
 
diff --git a/stdlib/source/lux/target/js.lux b/stdlib/source/lux/target/js.lux
index b66f40e05..429579655 100644
--- a/stdlib/source/lux/target/js.lux
+++ b/stdlib/source/lux/target/js.lux
@@ -79,18 +79,19 @@
 
   (def: sanitize
     (-> Text Text)
-    (`` (|>> (~~ (template [<find> <replace>]
+    (`` (|>> (~~ (template [<replace> <find>]
                    [(text.replace-all <find> <replace>)]
 
-                   ["\" "\\"]
-                   [text.tab "\t"]
-                   [text.vertical-tab "\v"]
-                   [text.null "\0"]
-                   [text.back-space "\b"]
-                   [text.form-feed "\f"]
-                   [text.new-line "\n"]
-                   [text.carriage-return "\r"]
-                   [text.double-quote (format "\" text.double-quote)]
+                   ["\\" "\"]
+                   ["\t" text.tab]
+                   ["\v" text.vertical-tab]
+                   ["\0" text.null]
+                   ["\b" text.back-space]
+                   ["\f" text.form-feed]
+                   ["\n" text.new-line]
+                   ["\r" text.carriage-return]
+                   [(format "\" text.double-quote)
+                    text.double-quote]
                    ))
              )))
 
@@ -170,8 +171,8 @@
            (text.enclose ["{"
                           close]))))
 
-  (def: #export (function name inputs body)
-    (-> Var (List Var) Statement Computation)
+  (def: #export (function! name inputs body)
+    (-> Var (List Var) Statement Statement)
     (|> body
         ..block
         (format "function " (:representation name)
@@ -180,6 +181,12 @@
                     (text.join-with ..argument-separator)
                     ..argument)
                 " ")
+        :abstraction))
+
+  (def: #export (function name inputs body)
+    (-> Var (List Var) Statement Computation)
+    (|> (..function! name inputs body)
+        :representation
         ..argument
         :abstraction))
 
@@ -392,7 +399,7 @@
 
   (def: #export (switch input cases default)
     (-> Expression (List [(List Literal) Statement]) (Maybe Statement) Statement)
-    (:abstraction (format "switch (" (:representation input) ")" text.new-line
+    (:abstraction (format "switch (" (:representation input) ") "
                           (|> (format (|> cases
                                           (list@map (.function (_ [when then])
                                                       (format (|> when
diff --git a/stdlib/source/lux/tool/compiler/language/lux/phase/generation/js.lux b/stdlib/source/lux/tool/compiler/language/lux/phase/generation/js.lux
index 114242fd7..76496ae82 100644
--- a/stdlib/source/lux/tool/compiler/language/lux/phase/generation/js.lux
+++ b/stdlib/source/lux/tool/compiler/language/lux/phase/generation/js.lux
@@ -1,9 +1,13 @@
 (.module:
   [lux #*
    [abstract
-    [monad (#+ do)]]]
+    [monad (#+ do)]]
+   [control
+    ["." exception (#+ exception:)]]
+   [target
+    ["_" js]]]
   ["." / #_
-   [runtime (#+ Phase)]
+   [runtime (#+ Phase Phase!)]
    ["#." primitive]
    ["#." structure]
    ["#." reference ("#@." system)]
@@ -20,7 +24,45 @@
       ["//#" /// #_
        ["#." phase ("#@." monad)]]]]]])
 
-(def: #export (generate archive synthesis)
+(exception: #export cannot-recur-as-an-expression)
+
+(def: (statement expression archive synthesis)
+  Phase!
+  (case synthesis
+    (^template [<tag>]
+      (^ (<tag> value))
+      (//////phase@map _.return (expression archive synthesis)))
+    ([synthesis.bit]
+     [synthesis.i64]
+     [synthesis.f64]
+     [synthesis.text]
+     [synthesis.variant]
+     [synthesis.tuple]
+     [#synthesis.Reference]
+     [synthesis.branch/get]
+     [synthesis.function/apply]
+     [#synthesis.Extension])
+
+    (^ (synthesis.branch/case case))
+    (/case.case! statement expression archive case)
+
+    (^ (synthesis.branch/let let))
+    (/case.let! statement expression archive let)
+
+    (^ (synthesis.branch/if if))
+    (/case.if! statement expression archive if)
+
+    (^ (synthesis.loop/scope scope))
+    (/loop.scope! statement expression archive scope)
+
+    (^ (synthesis.loop/recur updates))
+    (/loop.recur! statement expression archive updates)
+
+    (^ (synthesis.function/abstraction abstraction))
+    (//////phase@map _.return (/function.function statement expression archive abstraction))
+    ))
+
+(def: (expression archive synthesis)
   Phase
   (case synthesis
     (^template [<tag> <generator>]
@@ -32,38 +74,42 @@
      [synthesis.text /primitive.text])
 
     (^ (synthesis.variant variantS))
-    (/structure.variant generate archive variantS)
+    (/structure.variant expression archive variantS)
 
     (^ (synthesis.tuple members))
-    (/structure.tuple generate archive members)
+    (/structure.tuple expression archive members)
 
     (#synthesis.Reference value)
     (//reference.reference /reference.system archive value)
 
     (^ (synthesis.branch/case case))
-    (/case.case generate archive case)
+    (/case.case ..statement expression archive case)
 
     (^ (synthesis.branch/let let))
-    (/case.let generate archive let)
+    (/case.let expression archive let)
 
     (^ (synthesis.branch/if if))
-    (/case.if generate archive if)
+    (/case.if expression archive if)
 
     (^ (synthesis.branch/get get))
-    (/case.get generate archive get)
+    (/case.get expression archive get)
 
     (^ (synthesis.loop/scope scope))
-    (/loop.scope generate archive scope)
+    (/loop.scope ..statement expression archive scope)
 
     (^ (synthesis.loop/recur updates))
-    (/loop.recur generate archive updates)
+    (//////phase.throw ..cannot-recur-as-an-expression [])
 
     (^ (synthesis.function/abstraction abstraction))
-    (/function.function generate archive abstraction)
+    (/function.function ..statement expression archive abstraction)
 
     (^ (synthesis.function/apply application))
-    (/function.apply generate archive application)
+    (/function.apply expression archive application)
 
     (#synthesis.Extension extension)
-    (extension.apply archive generate extension)
+    (extension.apply archive expression extension)
     ))
+
+(def: #export generate
+  Phase
+  ..expression)
diff --git a/stdlib/source/lux/tool/compiler/language/lux/phase/generation/js/case.lux b/stdlib/source/lux/tool/compiler/language/lux/phase/generation/js/case.lux
index 700411c5f..ab1cc08de 100644
--- a/stdlib/source/lux/tool/compiler/language/lux/phase/generation/js/case.lux
+++ b/stdlib/source/lux/tool/compiler/language/lux/phase/generation/js/case.lux
@@ -14,7 +14,7 @@
    [target
     ["_" js (#+ Expression Computation Var Statement)]]]
   ["." // #_
-   ["#." runtime (#+ Operation Phase Generator)]
+   ["#." runtime (#+ Operation Phase Phase! Generator Generator!)]
    ["#." reference]
    ["#." primitive]
    ["/#" // #_
@@ -40,11 +40,18 @@
   (do ///////phase.monad
     [valueO (generate archive valueS)
      bodyO (generate archive bodyS)]
-    ## TODO: Find some way to do 'let' without paying the price of the closure.
     (wrap (_.apply/* (_.closure (list (..register register))
                                 (_.return bodyO))
                      (list valueO)))))
 
+(def: #export (let! statement expression archive [valueS register bodyS])
+  (Generator! [Synthesis Register Synthesis])
+  (do ///////phase.monad
+    [valueO (expression archive valueS)
+     bodyO (statement expression archive bodyS)]
+    (wrap (_.then (_.define (..register register) valueO)
+                  bodyO))))
+
 (def: #export (if generate archive [testS thenS elseS])
   (Generator [Synthesis Synthesis Synthesis])
   (do ///////phase.monad
@@ -53,6 +60,16 @@
      elseO (generate archive elseS)]
     (wrap (_.? testO thenO elseO))))
 
+(def: #export (if! statement expression archive [testS thenS elseS])
+  (Generator! [Synthesis Synthesis Synthesis])
+  (do ///////phase.monad
+    [testO (expression archive testS)
+     thenO (statement expression archive thenS)
+     elseO (statement expression archive elseS)]
+    (wrap (_.if testO
+            thenO
+            elseO))))
+
 (def: #export (get generate archive [pathP valueS])
   (Generator [(List Member) Synthesis])
   (do ///////phase.monad
@@ -138,8 +155,8 @@
           ..restore-cursor!
           post!)))
 
-(def: (optimized-pattern-matching recur generate archive pathP)
-  (-> (-> Path (Operation Statement)) Phase Archive
+(def: (optimized-pattern-matching recur pathP)
+  (-> (-> Path (Operation Statement))
       (-> Path (Operation (Maybe Statement))))
   (.case pathP
     (^template [<simple> <choice>]
@@ -194,12 +211,12 @@
     _
     (///////phase@wrap #.None)))
 
-(def: (pattern-matching' generate archive)
-  (-> Phase Archive
+(def: (pattern-matching' statement expression archive)
+  (-> Phase! Phase Archive
       (-> Path (Operation Statement)))
   (function (recur pathP)
     (do ///////phase.monad
-      [outcome (optimized-pattern-matching recur generate archive pathP)]
+      [outcome (optimized-pattern-matching recur pathP)]
       (.case outcome
         (#.Some outcome)
         (wrap outcome)
@@ -253,9 +270,7 @@
            [#/////synthesis.Text-Fork //primitive.text Text])
 
           (#/////synthesis.Then bodyS)
-          (do ///////phase.monad
-            [body! (generate archive bodyS)]
-            (wrap (_.return body!)))
+          (statement expression archive bodyS)
 
           (^template [<complex> <choice>]
             (^ (<complex> idx))
@@ -278,20 +293,20 @@
           ([/////synthesis.path/seq _.then]
            [/////synthesis.path/alt ..alternation]))))))
 
-(def: (pattern-matching generate archive pathP)
-  (-> Phase Archive Path (Operation Statement))
+(def: (pattern-matching statement expression archive pathP)
+  (-> Phase! Phase Archive Path (Operation Statement))
   (do ///////phase.monad
-    [pattern-matching! (pattern-matching' generate archive pathP)]
+    [pattern-matching! (pattern-matching' statement expression archive pathP)]
     (wrap ($_ _.then
               (_.do-while (_.boolean false)
                           pattern-matching!)
               (_.throw (_.string ////synthesis/case.pattern-matching-error))))))
 
-(def: #export (case generate archive [valueS pathP])
-  (Generator [Synthesis Path])
+(def: #export (case statement expression archive [valueS pathP])
+  (-> Phase! (Generator [Synthesis Path]))
   (do ///////phase.monad
-    [stack-init (generate archive valueS)
-     path! (pattern-matching generate archive pathP)
+    [stack-init (expression archive valueS)
+     path! (pattern-matching statement expression archive pathP)
      #let [closure (<| (_.closure (list))
                        ($_ _.then
                            (_.declare @temp)
@@ -299,3 +314,14 @@
                            (_.define @savepoint (_.array (list)))
                            path!))]]
     (wrap (_.apply/* closure (list)))))
+
+(def: #export (case! statement expression archive [valueS pathP])
+  (Generator! [Synthesis Path])
+  (do ///////phase.monad
+    [stack-init (expression archive valueS)
+     path! (pattern-matching statement expression archive pathP)]
+    (wrap ($_ _.then
+              (_.declare @temp)
+              (_.define @cursor (_.array (list stack-init)))
+              (_.define @savepoint (_.array (list)))
+              path!))))
diff --git a/stdlib/source/lux/tool/compiler/language/lux/phase/generation/js/function.lux b/stdlib/source/lux/tool/compiler/language/lux/phase/generation/js/function.lux
index b2b77ca08..3b491fd8e 100644
--- a/stdlib/source/lux/tool/compiler/language/lux/phase/generation/js/function.lux
+++ b/stdlib/source/lux/tool/compiler/language/lux/phase/generation/js/function.lux
@@ -6,12 +6,14 @@
     pipe]
    [data
     ["." product]
+    [text
+     ["%" format (#+ format)]]
     [collection
      ["." list ("#@." functor fold)]]]
    [target
-    ["_" js (#+ Expression Computation Var)]]]
+    ["_" js (#+ Expression Computation Var Statement)]]]
   ["." // #_
-   ["#." runtime (#+ Operation Phase Generator)]
+   ["#." runtime (#+ Operation Phase Phase! Generator)]
    ["#." reference]
    ["#." case]
    ["/#" // #_
@@ -19,7 +21,7 @@
     ["//#" /// #_
      [analysis (#+ Variant Tuple Environment Abstraction Application Analysis)]
      [synthesis (#+ Synthesis)]
-     ["#." generation]
+     ["#." generation (#+ Context)]
      ["//#" /// #_
       [arity (#+ Arity)]
       [reference
@@ -33,20 +35,21 @@
      argsO+ (monad.map @ (generate archive) argsS+)]
     (wrap (_.apply/* functionO argsO+))))
 
-(def: (with-closure inits function-definition)
-  (-> (List Expression) Computation (Operation Computation))
-  (///////phase@wrap
-   (case inits
-     #.Nil
-     function-definition
+(def: (with-closure @self inits function-body)
+  (-> Var (List Expression) Statement [Statement Expression])
+  (case inits
+    #.Nil
+    [(_.function! @self (list) function-body)
+     @self]
 
-     _
-     (let [capture (: (-> Register Var)
-                      (|>> (///reference.foreign //reference.system) :assume))
-           closure (_.closure (|> (list.enumerate inits)
-                                  (list@map (|>> product.left capture)))
-                              (_.return function-definition))]
-       (_.apply/* closure inits)))))
+    _
+    (let [capture (: (-> Register Var)
+                     (|>> (///reference.foreign //reference.system) :assume))]
+      [(_.function! @self
+                    (|> (list.enumerate inits)
+                        (list@map (|>> product.left capture)))
+                    (_.return (_.function @self (list) function-body)))
+       (_.apply/* @self inits)])))
 
 (def: @curried (_.var "curried"))
 
@@ -55,17 +58,22 @@
 
 (def: @@arguments (_.var "arguments"))
 
-(def: #export (function generate archive [environment arity bodyS])
-  (Generator (Abstraction Synthesis))
+(def: (@scope function-name)
+  (-> Context Text)
+  (format (///reference.artifact function-name) "_scope"))
+
+(def: #export (function statement expression archive [environment arity bodyS])
+  (-> Phase! (Generator (Abstraction Synthesis)))
   (do {@ ///////phase.monad}
-    [[function-name bodyO] (/////generation.with-new-context archive
+    [[function-name body!] (/////generation.with-new-context archive
                              (do @
-                               [function-name (:: @ map ///reference.artifact
-                                                  (/////generation.context archive))]
-                               (/////generation.with-anchor (_.var function-name)
-                                 (generate archive bodyS))))
+                               [scope (:: @ map ..@scope
+                                          (/////generation.context archive))]
+                               (/////generation.with-anchor [1 scope]
+                                 (statement expression archive bodyS))))
      #let [arityO (|> arity .int _.i32)
            @num-args (_.var "num_args")
+           @scope (..@scope function-name)
            @self (_.var (///reference.artifact function-name))
            apply-poly (.function (_ args func)
                         (|> func (_.do "apply" (list _.null args))))
@@ -75,34 +83,36 @@
                                         pre!
                                         (_.define (..input post) (_.at (_.i32 (.int post)) @@arguments))))
                                   initialize-self!
-                                  (list.indices arity))]]
-    (with-closure (list@map (///reference.variable //reference.system) environment)
-      (_.function @self (list)
-        ($_ _.then
-            (_.define @num-args (_.the "length" @@arguments))
-            (_.cond (list [(|> @num-args (_.= arityO))
-                           ($_ _.then
-                               initialize!
-                               (_.return bodyO))]
-                          [(|> @num-args (_.> arityO))
-                           (let [arity-inputs (|> (_.array (list))
-                                                  (_.the "slice")
-                                                  (_.do "call" (list @@arguments (_.i32 +0) arityO)))
-                                 extra-inputs (|> (_.array (list))
-                                                  (_.the "slice")
-                                                  (_.do "call" (list @@arguments arityO)))]
-                             (_.return (|> @self
-                                           (apply-poly arity-inputs)
-                                           (apply-poly extra-inputs))))])
-                    ## (|> @num-args (_.< arityO))
-                    (let [all-inputs (|> (_.array (list))
-                                         (_.the "slice")
-                                         (_.do "call" (list @@arguments)))]
-                      ($_ _.then
-                          (_.define @curried all-inputs)
-                          (_.return (_.closure (list)
-                                               (let [@missing all-inputs]
-                                                 (_.return (apply-poly (_.do "concat" (list @missing) @curried)
-                                                                       @self))))))))
-            )))
-    ))
+                                  (list.indices arity))
+           [definition instantiation] (with-closure @self (list@map (///reference.variable //reference.system) environment)
+                                        ($_ _.then
+                                            (_.define @num-args (_.the "length" @@arguments))
+                                            (_.cond (list [(|> @num-args (_.= arityO))
+                                                           ($_ _.then
+                                                               initialize!
+                                                               (_.with-label (_.label @scope)
+                                                                 (_.do-while (_.boolean true)
+                                                                             body!)))]
+                                                          [(|> @num-args (_.> arityO))
+                                                           (let [arity-inputs (|> (_.array (list))
+                                                                                  (_.the "slice")
+                                                                                  (_.do "call" (list @@arguments (_.i32 +0) arityO)))
+                                                                 extra-inputs (|> (_.array (list))
+                                                                                  (_.the "slice")
+                                                                                  (_.do "call" (list @@arguments arityO)))]
+                                                             (_.return (|> @self
+                                                                           (apply-poly arity-inputs)
+                                                                           (apply-poly extra-inputs))))])
+                                                    ## (|> @num-args (_.< arityO))
+                                                    (let [all-inputs (|> (_.array (list))
+                                                                         (_.the "slice")
+                                                                         (_.do "call" (list @@arguments)))]
+                                                      ($_ _.then
+                                                          (_.define @curried all-inputs)
+                                                          (_.return (_.closure (list)
+                                                                               (let [@missing all-inputs]
+                                                                                 (_.return (apply-poly (_.do "concat" (list @missing) @curried)
+                                                                                                       @self))))))))
+                                            ))]
+     _ (/////generation.save! true ["" (%.nat (product.right function-name))] definition)]
+    (wrap instantiation)))
diff --git a/stdlib/source/lux/tool/compiler/language/lux/phase/generation/js/loop.lux b/stdlib/source/lux/tool/compiler/language/lux/phase/generation/js/loop.lux
index 096993996..8863b30a3 100644
--- a/stdlib/source/lux/tool/compiler/language/lux/phase/generation/js/loop.lux
+++ b/stdlib/source/lux/tool/compiler/language/lux/phase/generation/js/loop.lux
@@ -4,47 +4,95 @@
     ["." monad (#+ do)]]
    [data
     ["." product]
-    ["." text]
+    ["." text
+     ["%" format (#+ format)]]
     [number
      ["n" nat]]
     [collection
-     ["." list ("#@." functor)]]]
+     ["." list ("#@." functor fold)]]]
    [target
-    ["_" js (#+ Computation Var)]]]
+    ["_" js (#+ Computation Var Expression Statement)]]]
   ["." // #_
-   [runtime (#+ Operation Phase Generator)]
+   [runtime (#+ Operation Phase Phase! Generator Generator!)]
    ["#." case]
    ["///#" //// #_
     [synthesis (#+ Scope Synthesis)]
     ["#." generation]
     ["//#" /// #_
-     ["#." phase]]]])
+     ["#." phase]
+     [reference
+      [variable (#+ Register)]]]]])
 
-(def: @scope (_.var "scope"))
+(def: @scope
+  (-> Nat Text)
+  (|>> %.nat (format "scope")))
 
-(def: #export (scope generate archive [start initsS+ bodyS])
-  (Generator (Scope Synthesis))
+(def: (setup initial? offset bindings body)
+  (-> Bit Register (List Expression) Statement Statement)
+  (|> bindings
+      list.enumerate
+      (list@map (function (_ [register value])
+                  (let [variable (//case.register (n.+ offset register))]
+                    (if initial?
+                      (_.define variable value)
+                      (_.set variable value)))))
+      list.reverse
+      (list@fold _.then body)))
+
+(def: #export (scope! statement expression archive [start initsS+ bodyS])
+  (Generator! (Scope Synthesis))
   (case initsS+
     ## function/false/non-independent loop
     #.Nil
-    (generate archive bodyS)
+    (statement expression archive bodyS)
 
     ## true loop
     _
-    (do {@ ///////phase.monad}
-      [initsO+ (monad.map @ (generate archive) initsS+)
-       bodyO (/////generation.with-anchor @scope
-               (generate archive bodyS))
-       #let [closure (_.function @scope
-                       (|> initsS+
-                           list.enumerate
-                           (list@map (|>> product.left (n.+ start) //case.register)))
-                       (_.return bodyO))]]
+    (do {! ///////phase.monad}
+      [@scope (:: ! map ..@scope /////generation.next)
+       initsO+ (monad.map ! (expression archive) initsS+)
+       body! (/////generation.with-anchor [start @scope]
+               (statement expression archive bodyS))]
+      (wrap (..setup true start initsO+
+                     (_.with-label (_.label @scope)
+                       (_.do-while (_.boolean true)
+                                   body!)))))))
+
+(def: #export (scope statement expression archive [start initsS+ bodyS])
+  (-> Phase! (Generator (Scope Synthesis)))
+  (case initsS+
+    ## function/false/non-independent loop
+    #.Nil
+    (expression archive bodyS)
+
+    ## true loop
+    _
+    (do {! ///////phase.monad}
+      [@scope (:: ! map ..@scope /////generation.next)
+       initsO+ (monad.map ! (expression archive) initsS+)
+       body! (/////generation.with-anchor [start @scope]
+               (statement expression archive bodyS))
+       #let [closure (_.closure
+                      (|> initsS+
+                          list.enumerate
+                          (list@map (|>> product.left (n.+ start) //case.register)))
+                      (_.with-label (_.label @scope)
+                        (_.do-while (_.boolean true)
+                                    body!)))]]
       (wrap (_.apply/* closure initsO+)))))
 
-(def: #export (recur generate archive argsS+)
-  (Generator (List Synthesis))
-  (do {@ ///////phase.monad}
-    [@scope /////generation.anchor
-     argsO+ (monad.map @ (generate archive) argsS+)]
-    (wrap (_.apply/* @scope argsO+))))
+(def: @temp (_.var "lux_recur_values"))
+
+(def: #export (recur! statement expression archive argsS+)
+  (Generator! (List Synthesis))
+  (do {! ///////phase.monad}
+    [[offset @scope] /////generation.anchor
+     argsO+ (monad.map ! (expression archive) argsS+)]
+    (wrap ($_ _.then
+              (_.define @temp (_.array argsO+))
+              (..setup false offset
+                       (|> argsO+
+                           list.enumerate
+                           (list@map (function (_ [idx _])
+                                       (_.at (_.i32 (.int idx)) @temp))))
+                       (_.continue-at (_.label @scope)))))))
diff --git a/stdlib/source/lux/tool/compiler/language/lux/phase/generation/js/runtime.lux b/stdlib/source/lux/tool/compiler/language/lux/phase/generation/js/runtime.lux
index 9356f7f8d..7c18df1b9 100644
--- a/stdlib/source/lux/tool/compiler/language/lux/phase/generation/js/runtime.lux
+++ b/stdlib/source/lux/tool/compiler/language/lux/phase/generation/js/runtime.lux
@@ -24,10 +24,12 @@
   ["." /// #_
    ["#." reference]
    ["//#" /// #_
-    ["#." synthesis]
+    ["#." synthesis (#+ Synthesis)]
     ["#." generation (#+ Buffer)]
     ["//#" /// (#+ Output)
      ["#." phase]
+     [reference
+      [variable (#+ Register)]]
      [meta
       [archive (#+ Archive)
        ["." artifact (#+ Registry)]]]]]]
@@ -35,7 +37,7 @@
 
 (template [<name> <base>]
   [(type: #export <name>
-     (<base> Var Expression Statement))]
+     (<base> [Register Text] Expression Statement))]
 
   [Operation /////generation.Operation]
   [Phase /////generation.Phase]
@@ -43,6 +45,12 @@
   [Bundle /////generation.Bundle]
   )
 
+(type: #export Phase!
+  (-> Phase Archive Synthesis (Operation Statement)))
+
+(type: #export (Generator! i)
+  (-> Phase! Phase Archive i (Operation Statement)))
+
 (type: #export (Generator i)
   (-> Phase Archive i (Operation Expression)))
 
diff --git a/stdlib/source/lux/tool/compiler/language/lux/phase/generation/jvm/runtime.lux b/stdlib/source/lux/tool/compiler/language/lux/phase/generation/jvm/runtime.lux
index 41153f29c..945a8d03c 100644
--- a/stdlib/source/lux/tool/compiler/language/lux/phase/generation/jvm/runtime.lux
+++ b/stdlib/source/lux/tool/compiler/language/lux/phase/generation/jvm/runtime.lux
@@ -18,12 +18,12 @@
     [text
      ["%" format (#+ format)]]]
    [target
-    [jvm
+    ["." jvm #_
      ["_" bytecode (#+ Label Bytecode)]
      ["." modifier (#+ Modifier) ("#@." monoid)]
      ["." field (#+ Field)]
      ["." method (#+ Method)]
-     ["." version]
+     ["#/." version]
      ["." class (#+ Class)]
      ["." constant
       [pool (#+ Resource)]]
@@ -45,6 +45,7 @@
        ["#/." count]]]]]
    ["//#" /// #_
     [//
+     ["." version]
      ["." synthesis]
      ["." generation]
      [///
@@ -52,7 +53,7 @@
       [arity (#+ Arity)]
       [reference
        [variable (#+ Register)]]
-      ["." meta
+      [meta
        [io (#+ lux-context)]
        [archive (#+ Archive)]]]]]])
 
@@ -81,7 +82,7 @@
 (def: #export (class-name [module id])
   (-> generation.Context Text)
   (format lux-context
-          "/" (%.nat meta.version)
+          "/" (%.nat version.version)
           "/" (%.nat module)
           "/" (%.nat id)))
 
@@ -509,7 +510,7 @@
                         class.final))
         bytecode (<| (format.run class.writer)
                      try.assume
-                     (class.class version.v6_0
+                     (class.class jvm/version.v6_0
                                   modifier
                                   (name.internal class)
                                   (name.internal (..reflection ^Object)) (list)
@@ -576,7 +577,7 @@
                                       (row.row)))
         bytecode (<| (format.run class.writer)
                      try.assume
-                     (class.class version.v6_0
+                     (class.class jvm/version.v6_0
                                   modifier
                                   (name.internal class)
                                   (name.internal (..reflection ^Object)) (list)
diff --git a/stdlib/source/lux/tool/compiler/language/lux/phase/generation/reference.lux b/stdlib/source/lux/tool/compiler/language/lux/phase/generation/reference.lux
index d2a4c21e0..a28e1918f 100644
--- a/stdlib/source/lux/tool/compiler/language/lux/phase/generation/reference.lux
+++ b/stdlib/source/lux/tool/compiler/language/lux/phase/generation/reference.lux
@@ -4,6 +4,7 @@
     [text
      ["%" format (#+ format)]]]]
   ["." //// #_
+   ["." version]
    ["#." generation (#+ Context)]
    ["//#" /// #_
     ["." reference (#+ Reference)
@@ -14,7 +15,10 @@
 
 (def: #export (artifact [module artifact])
   (-> Context Text)
-  (format "lux_" "m" (%.nat module) "a" (%.nat artifact)))
+  (format "lux_"
+          "v" (%.nat version.version)
+          "m" (%.nat module)
+          "a" (%.nat artifact)))
 
 (signature: #export (System expression)
   (: (-> Text expression)
diff --git a/stdlib/source/lux/tool/compiler/meta/io/archive.lux b/stdlib/source/lux/tool/compiler/meta/io/archive.lux
index 77d7b4689..216295d3f 100644
--- a/stdlib/source/lux/tool/compiler/meta/io/archive.lux
+++ b/stdlib/source/lux/tool/compiler/meta/io/archive.lux
@@ -74,7 +74,7 @@
   (All [!] (-> (file.System !) Static Path))
   (format (..unversioned-lux-archive system static)
           (:: system separator)
-          (%.nat ///.version)))
+          (%.nat version.version)))
 
 (def: (module system static module-id)
   (All [!] (-> (file.System !) Static archive.ID Path))
diff --git a/stdlib/source/lux/tool/compiler/meta/packager/script.lux b/stdlib/source/lux/tool/compiler/meta/packager/script.lux
index f391e43a8..20756c0cf 100644
--- a/stdlib/source/lux/tool/compiler/meta/packager/script.lux
+++ b/stdlib/source/lux/tool/compiler/meta/packager/script.lux
@@ -72,7 +72,7 @@
                                           {directive
                                            so-far}
                                           {directive
-                                           (:assume artifact)})))))
+                                           (:assume content)})))))
               so-far
               artifacts))
 
diff --git a/stdlib/source/program/licentia.lux b/stdlib/source/program/licentia.lux
index 5021eb5bb..b3765916f 100644
--- a/stdlib/source/program/licentia.lux
+++ b/stdlib/source/program/licentia.lux
@@ -37,7 +37,7 @@
    ["#." input]
    ["#." output]])
 
-(with-expansions [<expiry> (as-is "2019-04-01")]
+(with-expansions [<expiry> "2019-04-01"]
   (to-do <expiry> "Replace _.work with _.covered-work or _.licensed-work")
   (to-do <expiry> "Create a short notice to add as a comment to each file in the _.work"))
 
@@ -64,6 +64,7 @@
                                       json (|> raw-json
                                                (:coerce java/lang/String)
                                                java/lang/String::trim
+                                               (:coerce Text)
                                                (:: json.codec decode))
                                       license (json.run json /input.license)]
                                      (wrap (/output.license license))))