Merge pull request #12 from hdgarrood/stack

Add a `stack` accessor

Author: garyb

bower.json

@@ -20,6 +20,7 @@
     "package.json"
   ],
   "dependencies": {
-    "purescript-eff": "^0.1.2"
+    "purescript-eff": "^0.1.2",
+    "purescript-maybe": "^0.3.5"
   }
 }

docs/Control/Monad/Eff/Exception.md

@@ -1,7 +1,7 @@
 ## Module Control.Monad.Eff.Exception
 
 This module defines an effect, actions and handlers for working
-with Javascript exceptions.
+with JavaScript exceptions.
 
 #### `EXCEPTION`
 
@@ -17,7 +17,7 @@ This effect is used to annotate code which possibly throws exceptions
 data Error :: *
 ```
 
-The type of Javascript errors
+The type of JavaScript errors
 
 ##### Instances
 ``` purescript
@@ -30,15 +30,23 @@ Show Error
 error :: String -> Error
 ```
 
-Create a Javascript error, specifying a message
+Create a JavaScript error, specifying a message
 
 #### `message`
 
 ``` purescript
 message :: Error -> String
 ```
 
-Get the error message from a Javascript error
+Get the error message from a JavaScript error
+
+#### `stack`
+
+``` purescript
+stack :: Error -> Maybe String
+```
+
+Get the stack trace from a JavaScript error
 
 #### `throwException`
 

src/Control/Monad/Eff/Exception.js

@@ -15,6 +15,14 @@ exports.message = function (e) {
   return e.message;
 };
 
+exports.stackImpl = function (just) {
+  return function (nothing) {
+    return function (e) {
+      return e.stack ? just(e.stack) : nothing;
+    };
+  };
+};
+
 exports.throwException = function (e) {
   return function () {
     throw e;

src/Control/Monad/Eff/Exception.purs

@@ -1,36 +1,44 @@
 -- | This module defines an effect, actions and handlers for working
--- | with Javascript exceptions.
+-- | with JavaScript exceptions.
 
 module Control.Monad.Eff.Exception
   ( EXCEPTION()
   , Error()
   , error
   , message
+  , stack
   , throwException
   , catchException
   , throw
   ) where
 
 import Prelude
+import Data.Maybe (Maybe(..))
 import Control.Monad.Eff (Eff())
 
 -- | This effect is used to annotate code which possibly throws exceptions
 foreign import data EXCEPTION :: !
 
--- | The type of Javascript errors
+-- | The type of JavaScript errors
 foreign import data Error :: *
 
 instance showError :: Show Error where
   show = showErrorImpl
 
 foreign import showErrorImpl :: Error -> String
 
--- | Create a Javascript error, specifying a message
+-- | Create a JavaScript error, specifying a message
 foreign import error :: String -> Error
 
--- | Get the error message from a Javascript error
+-- | Get the error message from a JavaScript error
 foreign import message :: Error -> String
 
+-- | Get the stack trace from a JavaScript error
+stack :: Error -> Maybe String
+stack = stackImpl Just Nothing
+
+foreign import stackImpl :: (forall a. a -> Maybe a) -> (forall a. Maybe a) -> Error -> Maybe String
+
 -- | Throw an exception
 -- |
 -- | For example: