- Added safe (single-threaded) mutation.

5 files changed, 187 insertions, 1 deletions

diff --git a/luxc/src/lux/analyser/proc/common.clj b/luxc/src/lux/analyser/proc/common.clj
index 7031a9135..e3951da18 100644
--- a/luxc/src/lux/analyser/proc/common.clj
+++ b/luxc/src/lux/analyser/proc/common.clj
@@ -436,6 +436,41 @@
         (return (&/|list (&&/|meta exo-type _cursor
                                    (&&/$proc (&/T ["atom" "compare-and-swap"]) (&/|list =atom =old =new) (&/|list)))))))))
 
+(defn ^:private analyse-box-new [analyse exo-type ?values]
+  (&type/with-var
+    (fn [$var]
+      (|do [:let [(&/$Cons ?init (&/$Nil)) ?values]
+            =init (&&/analyse-1 analyse $var ?init)
+            _ (&type/check exo-type (&/$UnivQ (&/|list) (&type/Box (&/$Bound 1) $var)))
+            _cursor &/cursor]
+        (return (&/|list (&&/|meta exo-type _cursor
+                                   (&&/$proc (&/T ["box" "new"]) (&/|list =init) (&/|list)))))))))
+
+(defn ^:private analyse-box-read [analyse exo-type ?values]
+  (&type/with-var
+    (fn [threadT]
+      (&type/with-var
+        (fn [valueT]
+          (|do [:let [(&/$Cons boxC (&/$Nil)) ?values]
+                boxA (&&/analyse-1 analyse (&type/Box threadT valueT) boxC)
+                _ (&type/check exo-type valueT)
+                _cursor &/cursor]
+            (return (&/|list (&&/|meta exo-type _cursor
+                                       (&&/$proc (&/T ["box" "read"]) (&/|list boxA) (&/|list)))))))))))
+
+(defn ^:private analyse-box-write [analyse exo-type ?values]
+  (&type/with-var
+    (fn [threadT]
+      (&type/with-var
+        (fn [valueT]
+          (|do [:let [(&/$Cons valueC (&/$Cons boxC (&/$Nil))) ?values]
+                boxA (&&/analyse-1 analyse (&type/Box threadT valueT) boxC)
+                valueA (&&/analyse-1 analyse valueT valueC)
+                _ (&type/check exo-type &/$Unit)
+                _cursor &/cursor]
+            (return (&/|list (&&/|meta exo-type _cursor
+                                       (&&/$proc (&/T ["box" "write"]) (&/|list valueA boxA) (&/|list)))))))))))
+
 (defn ^:private analyse-process-concurrency-level [analyse exo-type ?values]
   (|do [:let [(&/$Nil) ?values]
         _ (&type/check exo-type &type/Nat)
@@ -465,6 +500,10 @@
          "lux is"                   (analyse-lux-is analyse exo-type ?values)
          "lux try"                  (analyse-lux-try analyse exo-type ?values)
 
+         "lux box new"                 (analyse-box-new analyse exo-type ?values)
+         "lux box read"                (analyse-box-read analyse exo-type ?values)
+         "lux box write"               (analyse-box-write analyse exo-type ?values)
+         
          "lux io log"                  (analyse-io-log analyse exo-type ?values)
          "lux io error"                (analyse-io-error analyse exo-type ?values)
          "lux io exit"                 (analyse-io-exit analyse exo-type ?values)
diff --git a/luxc/src/lux/compiler/jvm/proc/common.clj b/luxc/src/lux/compiler/jvm/proc/common.clj
index bead93256..b23a59ce1 100644
--- a/luxc/src/lux/compiler/jvm/proc/common.clj
+++ b/luxc/src/lux/compiler/jvm/proc/common.clj
@@ -759,6 +759,47 @@
                   &&/wrap-boolean)]]
     (return nil)))
 
+(defn ^:private compile-box-new [compile ?values special-args]
+  (|do [:let [(&/$Cons initS (&/$Nil)) ?values]
+        ^MethodVisitor *writer* &/get-writer
+        :let [_ (doto *writer*
+                  (.visitLdcInsn (int 1))
+                  (.visitTypeInsn Opcodes/ANEWARRAY "java/lang/Object"))]
+        :let [_ (doto *writer*
+                  (.visitInsn Opcodes/DUP)
+                  (.visitLdcInsn (int 0)))]
+        _ (compile initS)
+        :let [_ (doto *writer*
+                  (.visitInsn Opcodes/AASTORE))]]
+    (return nil)))
+
+(defn ^:private compile-box-read [compile ?values special-args]
+  (|do [:let [(&/$Cons boxS (&/$Nil)) ?values
+              ;; (&/$Nil) special-args
+              ]
+        ^MethodVisitor *writer* &/get-writer
+        _ (compile boxS)
+        :let [_ (doto *writer*
+                  (.visitTypeInsn Opcodes/CHECKCAST "[Ljava/lang/Object;")
+                  (.visitLdcInsn (int 0))
+                  (.visitInsn Opcodes/AALOAD))]]
+    (return nil)))
+
+(defn ^:private compile-box-write [compile ?values special-args]
+  (|do [:let [(&/$Cons valueS (&/$Cons boxS (&/$Nil))) ?values
+              ;; (&/$Nil) special-args
+              ]
+        ^MethodVisitor *writer* &/get-writer
+        _ (compile boxS)
+        :let [_ (doto *writer*
+                  (.visitTypeInsn Opcodes/CHECKCAST "[Ljava/lang/Object;")
+                  (.visitLdcInsn (int 0)))]
+        _ (compile valueS)
+        :let [_ (doto *writer*
+                  (.visitInsn Opcodes/AASTORE)
+                  (.visitLdcInsn &/unit-tag))]]
+    (return nil)))
+
 (defn ^:private compile-process-concurrency-level [compile ?values special-args]
   (|do [:let [(&/$Nil) ?values]
         ^MethodVisitor *writer* &/get-writer
@@ -929,6 +970,13 @@
       "pow" (compile-math-pow compile ?values special-args)
       )
 
+    "box"
+    (case proc
+      "new" (compile-box-new compile ?values special-args)
+      "read" (compile-box-read compile ?values special-args)
+      "write" (compile-box-write compile ?values special-args)
+      )
+
     "atom"
     (case proc
       "new" (compile-atom-new compile ?values special-args)
diff --git a/stdlib/source/lux/control/thread.lux b/stdlib/source/lux/control/thread.lux
new file mode 100644
index 000000000..daee09900
--- /dev/null
+++ b/stdlib/source/lux/control/thread.lux
@@ -0,0 +1,78 @@
+(.module:
+  lux
+  (lux (control [functor #+ Functor]
+                [applicative #+ Applicative]
+                [monad #+ Monad do])
+       [io #+ IO]))
+
+(type: #export (Thread ! a)
+  (-> ! a))
+
+(type: #export (Box t v)
+  {#.doc "A mutable box holding a value."}
+  (#.Primitive "#Box" (~ (list t v))))
+
+(def: #export (box init)
+  (All [a] (-> a (All [!] (Thread ! (Box ! a)))))
+  (function [!]
+    ("lux box new" init)))
+
+(def: #export (read box)
+  (All [! a] (-> (Box ! a) (Thread ! a)))
+  (function [!]
+    ("lux box read" box)))
+
+(def: #export (write value box)
+  (All [a] (-> a (All [!] (-> (Box ! a) (Thread ! Unit)))))
+  (function [!]
+    ("lux box write" value box)))
+
+(def: #export (run thread)
+  (All [a]
+    (-> (All [!] (Thread ! a))
+        a))
+  (thread []))
+
+(struct: #export Functor<Thread>
+  (All [!] (Functor (Thread !)))
+
+  (def: (map f)
+    (function [fa]
+      (function [!]
+        (f (fa !))))))
+
+(struct: #export Applicative<Thread>
+  (All [!] (Applicative (Thread !)))
+
+  (def: functor Functor<Thread>)
+
+  (def: (wrap value)
+    (function [!]
+      value))
+  
+  (def: (apply ff fa)
+    (function [!]
+      ((ff !) (fa !)))))
+
+(struct: #export Monad<Thread>
+  (All [!] (Monad (Thread !)))
+
+  (def: applicative Applicative<Thread>)
+
+  (def: (join ffa)
+    (function [!]
+      ((ffa !) !))))
+
+(def: #export (update f box)
+  (All [a] (-> (-> a a) (All [!] (-> (Box ! a) (Thread ! a)))))
+  (do Monad<Thread>
+    [old (read box)
+     _ (write (f old) box)]
+    (wrap old)))
+
+(def: #export (io thread)
+  (All [a]
+    (-> (All [!] (Thread ! a))
+        (IO a)))
+  (function [void]
+    (thread void)))
diff --git a/stdlib/test/test/lux/control/thread.lux b/stdlib/test/test/lux/control/thread.lux
new file mode 100644
index 000000000..3dd27d0ad
--- /dev/null
+++ b/stdlib/test/test/lux/control/thread.lux
@@ -0,0 +1,20 @@
+(.module:
+  lux
+  (lux (control [monad #+ do]
+                ["/" thread])))
+
+(def: _test0_
+  Nat
+  (/.run (do /.Monad<Thread>
+           [box (/.box +123)
+            old (/.update (n/* +2) box)
+            new (/.read box)]
+           (wrap (n/+ old new)))))
+
+(def: _test1_
+  (All [!] (/.Thread ! Nat))
+  (do /.Monad<Thread>
+    [box (/.box +123)
+     old (/.update (n/* +2) box)
+     new (/.read box)]
+    (wrap (n/+ old new))))
diff --git a/stdlib/test/tests.lux b/stdlib/test/tests.lux
index ecce3d56b..87f9c913d 100644
--- a/stdlib/test/tests.lux
+++ b/stdlib/test/tests.lux
@@ -21,7 +21,8 @@
                       ["_." reader]
                       ["_." writer]
                       ["_." state]
-                      ["_." parser])
+                      ["_." parser]
+                      ["_." thread])
              (data ["_." bit]
                    ["_." bool]
                    ["_." error]