Basic STStrMap, allowing efficient mutation of records

Author: dylex

README.md

@@ -196,8 +196,41 @@
     values :: forall a. StrMap a -> [a]
 
 
+## Module Data.StrMap.ST
+
+### Types
+
+    data STStrMap :: * -> * -> *
+
+
+### Values
+
+    delete :: forall a h r. STStrMap h a -> String -> Eff (st :: ST h | r) (STStrMap h a)
+
+    freeze :: forall a h r. STStrMap h a -> Eff (st :: ST h | r) (SM.StrMap a)
+
+    isEmpty :: forall a h r. STStrMap h a -> Eff (st :: ST h | r) Boolean
+
+    new :: forall a h r. Eff (st :: ST h | r) (STStrMap h a)
+
+    peek :: forall a h r. STStrMap h a -> String -> Eff (st :: ST h | r) (Maybe a)
+
+    poke :: forall a h r. STStrMap h a -> String -> a -> Eff (st :: ST h | r) a
+
+    size :: forall a h r. STStrMap h a -> Eff (st :: ST h | r) Number
+
+    thaw :: forall a h r. SM.StrMap a -> Eff (st :: ST h | r) (STStrMap h a)
+
+
+## Module Data.StrMap.ST.Unsafe
+
+### Values
+
+    unsafePeek :: forall a h r. STStrMap h a -> String -> Eff (st :: ST h | r) a
+
+
 ## Module Data.StrMap.Unsafe
 
 ### Values
 
-    unsafeIndex :: forall a. StrMap a -> String -> a
+    unsafeIndex :: forall a. StrMap a -> String -> a

src/Data/StrMap/ST.purs

@@ -0,0 +1,86 @@
+module Data.StrMap.ST
+  ( STStrMap()
+  , new
+  , freeze
+  , thaw
+  , isEmpty
+  , peek
+  , size
+  , poke
+  , delete
+  ) where
+
+import Control.Monad.Eff
+import Control.Monad.ST
+import Data.Maybe
+
+import qualified Data.StrMap as SM
+
+foreign import data STStrMap :: * -> * -> *
+
+foreign import _new """
+  function _new() {
+    return {};
+  }""" :: forall a h r. Eff (st :: ST h | r) (STStrMap h a)
+
+new :: forall a h r. Eff (st :: ST h | r) (STStrMap h a)
+new = _new
+
+foreign import _copy """
+  function _copy(m) {
+    return function () {
+      var r = {};
+      for (var k in m)
+        r[k] = m[k];
+      return r;
+    };
+  }""" :: forall a b h r. a -> Eff (st :: ST h | r) b
+
+thaw :: forall a h r. SM.StrMap a -> Eff (st :: ST h | r) (STStrMap h a)
+thaw = _copy
+
+freeze :: forall a h r. STStrMap h a -> Eff (st :: ST h | r) (SM.StrMap a)
+freeze = _copy 
+
+foreign import _unST """
+  function _unST(m) {
+    return m;
+  }""" :: forall a h. STStrMap h a -> SM.StrMap a
+
+isEmpty :: forall a h r. STStrMap h a -> Eff (st :: ST h | r) Boolean
+isEmpty m = return (SM.isEmpty (_unST m))
+
+peek :: forall a h r. STStrMap h a -> String -> Eff (st :: ST h | r) (Maybe a)
+peek m k = return (SM.lookup k (_unST m))
+
+size :: forall a h r. STStrMap h a -> Eff (st :: ST h | r) Number
+size m = return (SM.size (_unST m))
+
+foreign import poke """
+  function poke(m) {
+    return function (k) {
+      return function (v) {
+        return function () {
+          return m[k] = v;
+        };
+      };
+    };
+  }""" :: forall a h r. STStrMap h a -> String -> a -> Eff (st :: ST h | r) a
+
+foreign import _delete """
+  function _delete(m) {
+    return function (k) {
+      return function () {
+        delete m[k];
+        return m;
+      };
+    };
+  }""" :: forall a h r. STStrMap h a -> String -> Eff (st :: ST h | r) (STStrMap h a)
+
+delete :: forall a h r. STStrMap h a -> String -> Eff (st :: ST h | r) (STStrMap h a)
+delete = _delete
+
+foreign import run """
+  function run(f) {
+    return f;
+  }""" :: forall a r. (forall h. Eff (st :: ST h | r) (STStrMap h a)) -> Eff r (SM.StrMap a)

src/Data/StrMap/ST/Unsafe.purs

@@ -0,0 +1,17 @@
+module Data.StrMap.ST.Unsafe
+  ( unsafePeek
+  ) where
+
+import Control.Monad.Eff
+import Control.Monad.ST
+import Data.StrMap.Unsafe
+import Data.StrMap.ST
+
+foreign import unsafePeek """
+  function unsafePeek(m) {
+    return function (k) {
+      return function () {
+        return m[k];
+      }
+    }
+  }""" :: forall a h r. STStrMap h a -> String -> Eff (st :: ST h | r) a