Re-factored the UTF8 codec into its own module.

10 files changed, 223 insertions, 194 deletions

diff --git a/stdlib/source/lux/control/parser/binary.lux b/stdlib/source/lux/control/parser/binary.lux
index 7221f5c65..37423b091 100644
--- a/stdlib/source/lux/control/parser/binary.lux
+++ b/stdlib/source/lux/control/parser/binary.lux
@@ -11,7 +11,8 @@
     ["/" binary (#+ Binary)]
     [text
      ["%" format (#+ format)]
-     ["." encoding]]
+     [encoding
+      ["." utf8]]]
     [collection
      ["." list]
      ["." row (#+ Row)]
@@ -169,7 +170,7 @@
      (Parser Text)
      (do //.monad
        [utf8 <binary>]
-       (//.lift (\ encoding.utf8 decode utf8))))]
+       (//.lift (\ utf8.codec decode utf8))))]
 
   [utf8/8  ..binary/8]
   [utf8/16 ..binary/16]
diff --git a/stdlib/source/lux/data/format/binary.lux b/stdlib/source/lux/data/format/binary.lux
index 62ef08f4b..0cf1fbdd0 100644
--- a/stdlib/source/lux/data/format/binary.lux
+++ b/stdlib/source/lux/data/format/binary.lux
@@ -15,8 +15,9 @@
     ["." product]
     ["." binary (#+ Binary)]
     [text
-     ["." encoding]
-     ["%" format (#+ format)]]
+     ["%" format (#+ format)]
+     [encoding
+      ["." utf8]]]
     [collection
      ["." list]
      ["." row (#+ Row) ("#\." functor)]
@@ -164,7 +165,7 @@
 (template [<name> <binary>]
   [(def: #export <name>
      (Writer Text)
-     (|>> (\ encoding.utf8 encode) <binary>))]
+     (|>> (\ utf8.codec encode) <binary>))]
 
   [utf8/8  ..binary/8]
   [utf8/16 ..binary/16]
diff --git a/stdlib/source/lux/data/format/tar.lux b/stdlib/source/lux/data/format/tar.lux
index 7d4968239..504b7f5ac 100644
--- a/stdlib/source/lux/data/format/tar.lux
+++ b/stdlib/source/lux/data/format/tar.lux
@@ -13,7 +13,8 @@
     ["." binary (#+ Binary)]
     ["." text (#+ Char)
      ["%" format (#+ format)]
-     ["." encoding]]
+     [encoding
+      ["." utf8]]]
     ["." format #_
      ["#" binary (#+ Writer) ("#\." monoid)]]
     [collection
@@ -86,7 +87,7 @@
               (\ n.octal encode)
               (..octal_padding <size>)
               (text.suffix suffix)
-              (\ encoding.utf8 encode)
+              (\ utf8.codec encode)
               (format.segment padded_size))))
 
      (def: <coercion>
@@ -127,7 +128,7 @@
   (Parser Small)
   (do <>.monad
     [digits (<b>.segment ..small_size)
-     digits (<>.lift (\ encoding.utf8 decode digits))
+     digits (<>.lift (\ utf8.codec decode digits))
      _ ..verify_small_suffix]
     (<>.lift
      (do {! try.monad}
@@ -138,7 +139,7 @@
   (Parser Big)
   (do <>.monad
     [digits (<b>.segment ..big_size)
-     digits (<>.lift (\ encoding.utf8 decode digits))
+     digits (<>.lift (\ utf8.codec decode digits))
      end <b>.bits/8
      _ (let [expected (`` (char (~~ (static ..blank))))]
          (<>.assert (exception.construct ..wrong_character [expected end])
@@ -169,7 +170,7 @@
   (def: checksum_checksum
     (|> ..dummy_checksum
         :representation
-        (\ encoding.utf8 encode)
+        (\ utf8.codec encode)
         ..checksum))
 
   (def: checksum_code
@@ -187,14 +188,14 @@
     (let [padded_size (n.+ (text.size ..checksum_suffix)
                            ..small_size)]
       (|>> :representation
-           (\ encoding.utf8 encode)
+           (\ utf8.codec encode)
            (format.segment padded_size))))
 
   (def: checksum_parser
     (Parser [Nat Checksum])
     (do <>.monad
       [ascii (<b>.segment ..small_size)
-       digits (<>.lift (\ encoding.utf8 decode ascii))
+       digits (<>.lift (\ utf8.codec decode ascii))
        _ ..verify_small_suffix
        value (<>.lift
               (\ n.octal decode digits))]
@@ -208,7 +209,7 @@
 
 (def: ascii?
   (-> Text Bit)
-  (|>> (\ encoding.utf8 encode)
+  (|>> (\ utf8.codec encode)
        (binary.fold (function (_ char verdict)
                       (.and verdict
                             (n.<= ..last_ascii char)))
@@ -227,7 +228,7 @@
     0 (#try.Success string)
     size (loop [end (dec size)]
            (case end
-             0 (#try.Success (\ encoding.utf8 encode ""))
+             0 (#try.Success (\ utf8.codec encode ""))
              _ (do try.monad
                  [last_char (binary.read/8 end string)]
                  (`` (case (.nat last_char)
@@ -250,7 +251,7 @@
      (def: #export (<in> value)
        (-> <representation> (Try <type>))
        (if (..ascii? value)
-         (if (|> value (\ encoding.utf8 encode) binary.size (n.<= <size>))
+         (if (|> value (\ utf8.codec encode) binary.size (n.<= <size>))
            (#try.Success (:abstraction value))
            (exception.throw <exception> [value]))
          (exception.throw ..not_ascii [value])))
@@ -265,7 +266,7 @@
              padded_size (n.+ (text.size suffix) <size>)]
          (|>> :representation
               (text.suffix suffix)
-              (\ encoding.utf8 encode)
+              (\ utf8.codec encode)
               (format.segment padded_size))))
 
      (def: <parser>
@@ -279,7 +280,7 @@
          (<>.lift
           (do {! try.monad}
             [ascii (..un_pad string)
-             text (\ encoding.utf8 decode ascii)]
+             text (\ utf8.codec decode ascii)]
             (<in> text)))))
 
      (def: #export <none>
@@ -307,7 +308,7 @@
     (let [padded_size (n.+ (text.size ..null)
                            ..magic_size)]
       (|>> :representation
-           (\ encoding.utf8 encode)
+           (\ utf8.codec encode)
            (format.segment padded_size))))
 
   (def: magic_parser
@@ -320,7 +321,7 @@
                     (n.= expected end))]
       (<>.lift
        (\ try.monad map (|>> :abstraction)
-          (\ encoding.utf8 decode string)))))
+          (\ utf8.codec decode string)))))
   )
 
 (def: block_size Size 512)
@@ -742,7 +743,7 @@
   (-> Checksum Binary Nat)
   (let [|checksum| (|> checksum
                        ..from_checksum
-                       (\ encoding.utf8 encode)
+                       (\ utf8.codec encode)
                        ..checksum)]
     (|> (..checksum header)
         (n.- |checksum|)
diff --git a/stdlib/source/lux/data/text/encoding.lux b/stdlib/source/lux/data/text/encoding.lux
index 7445d5ebc..92f68dfe0 100644
--- a/stdlib/source/lux/data/text/encoding.lux
+++ b/stdlib/source/lux/data/text/encoding.lux
@@ -1,13 +1,5 @@
 (.module:
   [lux #*
-   ["@" target]
-   ["." ffi]
-   [abstract
-    [codec (#+ Codec)]]
-   [control
-    ["." try (#+ Try)]]
-   [data
-    ["." binary (#+ Binary)]]
    [type
     abstract]])
 
@@ -168,150 +160,3 @@
     (-> Encoding Text)
     (|>> :representation))
   )
-
-(with_expansions [<jvm> (as_is (ffi.import: java/lang/String
-                                 ["#::."
-                                  (new [[byte] java/lang/String])
-                                  (getBytes [java/lang/String] [byte])]))]
-  (for {@.old (as_is <jvm>)
-        @.jvm (as_is <jvm>)
-
-        @.js
-        (as_is (ffi.import: Uint8Array)
-
-               ## On Node
-               (ffi.import: Buffer
-                 (#static from #as from|encode [ffi.String ffi.String] Buffer)
-                 (#static from #as from|decode [Uint8Array] Buffer)
-                 (toString [ffi.String] ffi.String))
-
-               ## On the browser
-               (ffi.import: TextEncoder
-                 (new [ffi.String])
-                 (encode [ffi.String] Uint8Array))
-               
-               (ffi.import: TextDecoder
-                 (new [ffi.String])
-                 (decode [Uint8Array] ffi.String)))
-
-        @.ruby
-        (as_is (ffi.import: String #as RubyString
-                 (encode [Text] RubyString)
-                 (force_encoding [Text] Text)
-                 (bytes [] Binary))
-
-               (ffi.import: Array #as RubyArray
-                 (pack [Text] RubyString)))
-
-        @.php
-        (as_is (ffi.import: Almost_Binary)
-               (ffi.import: (unpack [ffi.String ffi.String] Almost_Binary))
-               (ffi.import: (array_values [Almost_Binary] Binary))
-               (def: php_byte_array_format "C*"))
-
-        @.scheme
-        ## https://srfi.schemers.org/srfi-140/srfi-140.html
-        (as_is (ffi.import: (string->utf8 [Text] Binary))
-               (ffi.import: (utf8->string [Binary] Text)))}
-       (as_is)))
-
-(def: (utf8\encode value)
-  (-> Text Binary)
-  (for {@.old
-        (java/lang/String::getBytes (..name ..utf_8)
-                                    ## TODO: Remove coercion below.
-                                    ## The coercion below may seem
-                                    ## gratuitous, but removing it
-                                    ## causes a grave compilation problem.
-                                    (:coerce java/lang/String value))
-
-        @.jvm
-        (java/lang/String::getBytes (..name ..utf_8) value)
-
-        @.js
-        (cond ffi.on_nashorn?
-              (:coerce Binary ("js object do" "getBytes" value ["utf8"]))
-              
-              ffi.on_node_js?
-              (|> (Buffer::from|encode [value "utf8"])
-                  ## This coercion is valid as per NodeJS's documentation:
-                  ## https://nodejs.org/api/buffer.html#buffer_buffers_and_typedarrays
-                  (:coerce Uint8Array))
-              
-              ## On the browser
-              (|> (TextEncoder::new [(..name ..utf_8)])
-                  (TextEncoder::encode [value]))
-              )
-
-        @.python
-        (:coerce Binary ("python apply" (:assume ("python constant" "bytearray")) value "utf-8"))
-
-        @.lua
-        ("lua utf8 encode" value)
-
-        @.ruby
-        (|> value
-            (:coerce RubyString)
-            (RubyString::encode ["UTF-8"])
-            (RubyString::bytes []))
-
-        @.php
-        (|> (..unpack [..php_byte_array_format value])
-            ..array_values
-            ("php object new" "ArrayObject")
-            (:coerce Binary))
-
-        @.scheme
-        (..string->utf8 value)}))
-
-(def: (utf8\decode value)
-  (-> Binary (Try Text))
-  (with_expansions [<jvm> (#try.Success (java/lang/String::new value (..name ..utf_8)))]
-    (for {@.old <jvm>
-          @.jvm <jvm>
-
-          @.js
-          (cond ffi.on_nashorn?
-                (|> ("js object new" ("js constant" "java.lang.String") [value "utf8"])
-                    (:coerce Text)
-                    #try.Success)
-
-                ffi.on_node_js?
-                (|> (Buffer::from|decode [value])
-                    (Buffer::toString ["utf8"])
-                    #try.Success)
-                
-                ## On the browser
-                (|> (TextDecoder::new [(..name ..utf_8)])
-                    (TextDecoder::decode [value])
-                    #try.Success))
-
-          @.python
-          (ffi.try (:coerce Text ("python object do" "decode" (:assume value) "utf-8")))
-
-          @.lua
-          (#try.Success ("lua utf8 decode" value))
-
-          @.ruby
-          (|> value
-              (:coerce RubyArray)
-              (RubyArray::pack ["C*"])
-              (:coerce RubyString)
-              (RubyString::force_encoding ["UTF-8"])
-              #try.Success)
-
-          @.php
-          (|> value
-              ("php pack" ..php_byte_array_format)
-              #try.Success)
-
-          @.scheme
-          (|> value
-              ..utf8->string
-              #try.Success)})))
-
-(structure: #export utf8
-  (Codec Binary Text)
-  
-  (def: encode ..utf8\encode)
-  (def: decode ..utf8\decode))
diff --git a/stdlib/source/lux/data/text/encoding/utf8.lux b/stdlib/source/lux/data/text/encoding/utf8.lux
new file mode 100644
index 000000000..01e4cd8a5
--- /dev/null
+++ b/stdlib/source/lux/data/text/encoding/utf8.lux
@@ -0,0 +1,158 @@
+(.module:
+  [lux #*
+   ["@" target]
+   ["." ffi]
+   [abstract
+    [codec (#+ Codec)]]
+   [control
+    ["." try (#+ Try)]]
+   [data
+    ["." binary (#+ Binary)]]]
+  ["." //])
+
+(with_expansions [<jvm> (as_is (ffi.import: java/lang/String
+                                 ["#::."
+                                  (new [[byte] java/lang/String])
+                                  (getBytes [java/lang/String] [byte])]))]
+  (for {@.old (as_is <jvm>)
+        @.jvm (as_is <jvm>)
+
+        @.js
+        (as_is (ffi.import: Uint8Array)
+
+               ## On Node
+               (ffi.import: Buffer
+                 (#static from #as from|encode [ffi.String ffi.String] Buffer)
+                 (#static from #as from|decode [Uint8Array] Buffer)
+                 (toString [ffi.String] ffi.String))
+
+               ## On the browser
+               (ffi.import: TextEncoder
+                 (new [ffi.String])
+                 (encode [ffi.String] Uint8Array))
+               
+               (ffi.import: TextDecoder
+                 (new [ffi.String])
+                 (decode [Uint8Array] ffi.String)))
+
+        @.ruby
+        (as_is (ffi.import: String #as RubyString
+                 (encode [Text] RubyString)
+                 (force_encoding [Text] Text)
+                 (bytes [] Binary))
+
+               (ffi.import: Array #as RubyArray
+                 (pack [Text] RubyString)))
+
+        @.php
+        (as_is (ffi.import: Almost_Binary)
+               (ffi.import: (unpack [ffi.String ffi.String] Almost_Binary))
+               (ffi.import: (array_values [Almost_Binary] Binary))
+               (def: php_byte_array_format "C*"))
+
+        @.scheme
+        ## https://srfi.schemers.org/srfi-140/srfi-140.html
+        (as_is (ffi.import: (string->utf8 [Text] Binary))
+               (ffi.import: (utf8->string [Binary] Text)))}
+       (as_is)))
+
+(def: (encode value)
+  (-> Text Binary)
+  (for {@.old
+        (java/lang/String::getBytes (//.name //.utf_8)
+                                    ## TODO: Remove coercion below.
+                                    ## The coercion below may seem
+                                    ## gratuitous, but removing it
+                                    ## causes a grave compilation problem.
+                                    (:coerce java/lang/String value))
+
+        @.jvm
+        (java/lang/String::getBytes (//.name //.utf_8) value)
+
+        @.js
+        (cond ffi.on_nashorn?
+              (:coerce Binary ("js object do" "getBytes" value ["utf8"]))
+              
+              ffi.on_node_js?
+              (|> (Buffer::from|encode [value "utf8"])
+                  ## This coercion is valid as per NodeJS's documentation:
+                  ## https://nodejs.org/api/buffer.html#buffer_buffers_and_typedarrays
+                  (:coerce Uint8Array))
+              
+              ## On the browser
+              (|> (TextEncoder::new [(//.name //.utf_8)])
+                  (TextEncoder::encode [value]))
+              )
+
+        @.python
+        (:coerce Binary ("python apply" (:assume ("python constant" "bytearray")) value "utf-8"))
+
+        @.lua
+        ("lua utf8 encode" value)
+
+        @.ruby
+        (|> value
+            (:coerce RubyString)
+            (RubyString::encode ["UTF-8"])
+            (RubyString::bytes []))
+
+        @.php
+        (|> (..unpack [..php_byte_array_format value])
+            ..array_values
+            ("php object new" "ArrayObject")
+            (:coerce Binary))
+
+        @.scheme
+        (..string->utf8 value)}))
+
+(def: (decode value)
+  (-> Binary (Try Text))
+  (with_expansions [<jvm> (#try.Success (java/lang/String::new value (//.name //.utf_8)))]
+    (for {@.old <jvm>
+          @.jvm <jvm>
+
+          @.js
+          (cond ffi.on_nashorn?
+                (|> ("js object new" ("js constant" "java.lang.String") [value "utf8"])
+                    (:coerce Text)
+                    #try.Success)
+
+                ffi.on_node_js?
+                (|> (Buffer::from|decode [value])
+                    (Buffer::toString ["utf8"])
+                    #try.Success)
+                
+                ## On the browser
+                (|> (TextDecoder::new [(//.name //.utf_8)])
+                    (TextDecoder::decode [value])
+                    #try.Success))
+
+          @.python
+          (ffi.try (:coerce Text ("python object do" "decode" (:assume value) "utf-8")))
+
+          @.lua
+          (#try.Success ("lua utf8 decode" value))
+
+          @.ruby
+          (|> value
+              (:coerce RubyArray)
+              (RubyArray::pack ["C*"])
+              (:coerce RubyString)
+              (RubyString::force_encoding ["UTF-8"])
+              #try.Success)
+
+          @.php
+          (|> value
+              ("php pack" ..php_byte_array_format)
+              #try.Success)
+
+          @.scheme
+          (|> value
+              ..utf8->string
+              #try.Success)})))
+
+(structure: #export codec
+  (Codec Binary Text)
+  
+  (def: encode ..encode)
+  (def: decode ..decode))
diff --git a/stdlib/source/lux/world/shell.lux b/stdlib/source/lux/world/shell.lux
index 482100853..dd6bc529d 100644
--- a/stdlib/source/lux/world/shell.lux
+++ b/stdlib/source/lux/world/shell.lux
@@ -20,7 +20,8 @@
     ["." product]
     ["." text
      ["%" format (#+ format)]
-     ["." encoding]]
+     [encoding
+      ["." utf8]]]
     [collection
      ["." array (#+ Array)]
      ["." list ("#\." fold functor)]
@@ -266,7 +267,7 @@
                                                    (..can_write
                                                     (function (_ message)
                                                       (|> jvm_output
-                                                          (java/io/OutputStream::write (\ encoding.utf8 encode message))))))
+                                                          (java/io/OutputStream::write (\ utf8.codec encode message))))))
                                                  (~~ (template [<name> <capability> <method>]
                                                        [(def: <name>
                                                           (<capability>
diff --git a/stdlib/source/test/lux/control/parser/binary.lux b/stdlib/source/test/lux/control/parser/binary.lux
index bc54ceada..943b8b3d5 100644
--- a/stdlib/source/test/lux/control/parser/binary.lux
+++ b/stdlib/source/test/lux/control/parser/binary.lux
@@ -18,8 +18,9 @@
     ["." bit]
     ["." name]
     ["." text ("#\." equivalence)
-     ["." encoding]
-     ["%" format (#+ format)]]
+     ["%" format (#+ format)]
+     [encoding
+      ["." utf8]]]
     ["." format #_
      ["#" binary]]
     [collection
@@ -52,8 +53,8 @@
 (def: (utf8_conversion_does_not_alter? value)
   (Predicate Text)
   (|> value
-      (\ encoding.utf8 encode)
-      (\ encoding.utf8 decode)
+      (\ utf8.codec encode)
+      (\ utf8.codec decode)
       (case> (#try.Success converted)
              (text\= value converted)
              
@@ -146,7 +147,7 @@
   (`` ($_ _.and
           (~~ (template [<parser> <format>]
                 [(do {! random.monad}
-                   [expected (\ ! map (\ encoding.utf8 encode) (random.ascii ..segment_size))]
+                   [expected (\ ! map (\ utf8.codec encode) (random.ascii ..segment_size))]
                    (_.cover [<parser> <format>]
                             (|> (format.run <format> expected)
                                 (/.run <parser>)
@@ -327,14 +328,14 @@
                            (/.run /.any)
                            (!expect (#try.Success _))))
               (do {! random.monad}
-                [data (\ ! map (\ encoding.utf8 encode) (random.ascii ..segment_size))]
+                [data (\ ! map (\ utf8.codec encode) (random.ascii ..segment_size))]
                 (_.cover [/.binary_was_not_fully_read]
                          (|> data
                              (/.run /.any)
                              (!expect (^multi (#try.Failure error)
                                               (exception.match? /.binary_was_not_fully_read error))))))
               (do {! random.monad}
-                [expected (\ ! map (\ encoding.utf8 encode) (random.ascii ..segment_size))]
+                [expected (\ ! map (\ utf8.codec encode) (random.ascii ..segment_size))]
                 (_.cover [/.segment format.segment format.run]
                          (|> expected
                              (format.run (format.segment ..segment_size))
@@ -342,7 +343,7 @@
                              (!expect (^multi (#try.Success actual)
                                               (\ binary.equivalence = expected actual))))))
               (do {! random.monad}
-                [data (\ ! map (\ encoding.utf8 encode) (random.ascii ..segment_size))]
+                [data (\ ! map (\ utf8.codec encode) (random.ascii ..segment_size))]
                 (_.cover [/.end?]
                          (|> data
                              (/.run (do <>.monad
@@ -354,7 +355,7 @@
                              (!expect (#try.Success #1)))))
               (do {! random.monad}
                 [to_read (\ ! map (n.% (inc ..segment_size)) random.nat)
-                 data (\ ! map (\ encoding.utf8 encode) (random.ascii ..segment_size))]
+                 data (\ ! map (\ utf8.codec encode) (random.ascii ..segment_size))]
                 (_.cover [/.Offset /.offset]
                          (|> data
                              (/.run (do <>.monad
@@ -369,7 +370,7 @@
                              (!expect (#try.Success #1)))))
               (do {! random.monad}
                 [to_read (\ ! map (n.% (inc ..segment_size)) random.nat)
-                 data (\ ! map (\ encoding.utf8 encode) (random.ascii ..segment_size))]
+                 data (\ ! map (\ utf8.codec encode) (random.ascii ..segment_size))]
                 (_.cover [/.remaining]
                          (|> data
                              (/.run (do <>.monad
diff --git a/stdlib/source/test/lux/data/format/tar.lux b/stdlib/source/test/lux/data/format/tar.lux
index c842ebe9c..c7250a025 100644
--- a/stdlib/source/test/lux/data/format/tar.lux
+++ b/stdlib/source/test/lux/data/format/tar.lux
@@ -14,7 +14,8 @@
     ["." binary ("#\." equivalence monoid)]
     ["." text ("#\." equivalence)
      ["%" format (#+ format)]
-     ["." encoding]
+     [encoding
+      ["." utf8]]
      ["." unicode #_
       ["#" set]
       ["#/." block]]]
@@ -163,7 +164,7 @@
      #let [content (|> chunk
                        (list.repeat chunks)
                        (text.join_with "")
-                       (\ encoding.utf8 encode))]]
+                       (\ utf8.codec encode))]]
     (`` ($_ _.and
             (~~ (template [<type> <tag>]
                   [(_.cover [<type>]
diff --git a/stdlib/source/test/lux/data/text/encoding.lux b/stdlib/source/test/lux/data/text/encoding.lux
index 9a9ba67cf..b4e47d7ee 100644
--- a/stdlib/source/test/lux/data/text/encoding.lux
+++ b/stdlib/source/test/lux/data/text/encoding.lux
@@ -21,7 +21,9 @@
     [number
      ["n" nat]]]]
   {1
-   ["." /]})
+   ["." /]}
+  ["." / #_
+   ["#." utf8]])
 
 (with_expansions [<encodings> (as_is [all/a
                                       [/.ascii]]
@@ -68,7 +70,7 @@
                                        /.ibm_874
                                        /.ibm_875]]
 
-                                     [all/ibm>900
+                                     [all/ibm<1000
                                       [/.ibm_918
                                        /.ibm_921
                                        /.ibm_922
@@ -220,12 +222,11 @@
     (<| (_.covering /._)
         (_.for [/.Encoding])
         (`` ($_ _.and
-                (_.for [/.utf8]
-                       ($codec.spec text.equivalence /.utf8 (random.unicode 5)))
-                
                 (~~ (template [<definition> <by_letter>]
                       [<definition>]
                       
                       <encodings>))
+
+                /utf8.test
                 ))))
   )
diff --git a/stdlib/source/test/lux/data/text/encoding/utf8.lux b/stdlib/source/test/lux/data/text/encoding/utf8.lux
new file mode 100644
index 000000000..3d376811d
--- /dev/null
+++ b/stdlib/source/test/lux/data/text/encoding/utf8.lux
@@ -0,0 +1,19 @@
+(.module:
+  [lux #*
+   ["_" test (#+ Test)]
+   [abstract
+    {[0 #spec]
+     [/
+      ["$." codec]]}]
+   [data
+    ["." text]]
+   [math
+    ["." random (#+ Random)]]]
+  {1
+   ["." /]})
+
+(def: #export test
+  Test
+  (<| (_.covering /._)
+      (_.for [/.codec]
+             ($codec.spec text.equivalence /.codec (random.unicode 5)))))