5 files changed, 37 insertions, 0 deletions

diff --git a/docs/PursLoader/Debug.md b/docs/PursLoader/Debug.md
new file mode 100644
index 0000000..824a9f8
--- /dev/null
+++ b/docs/PursLoader/Debug.md
@@ -0,0 +1,9 @@
+## Module PursLoader.Debug
+
+#### `debug`
+
+``` purescript
+debug :: forall eff. String -> Eff (loader :: Loader | eff) Unit
+```
+
+
diff --git a/package.json b/package.json
index 4d1dff2..e1a79d6 100644
--- a/package.json
+++ b/package.json
@@ -26,6 +26,7 @@
   "dependencies": {
     "async": "^1.3.0",
     "chalk": "^1.1.0",
+    "debug": "^2.2.0",
     "loader-utils": "^0.2.6"
   }
 }
diff --git a/src/PursLoader/Debug.js b/src/PursLoader/Debug.js
new file mode 100644
index 0000000..85eca10
--- /dev/null
+++ b/src/PursLoader/Debug.js
@@ -0,0 +1,12 @@
+'use strict';
+
+// module PursLoader.Debug
+
+var debug_ = require('debug')('purs-loader');
+
+function debug(message) {
+  return function(){
+    debug_(message);
+  };
+}
+exports.debug = debug;
diff --git a/src/PursLoader/Debug.purs b/src/PursLoader/Debug.purs
new file mode 100644
index 0000000..7a02f69
--- /dev/null
+++ b/src/PursLoader/Debug.purs
@@ -0,0 +1,9 @@
+module PursLoader.Debug (debug) where
+
+import Prelude (Unit())
+
+import Control.Monad.Eff (Eff())
+
+import PursLoader.LoaderRef (Loader())
+
+foreign import debug :: forall eff. String -> Eff (loader :: Loader | eff) Unit
diff --git a/src/PursLoader/Loader.purs b/src/PursLoader/Loader.purs
index f78153f..5e00f7e 100644
--- a/src/PursLoader/Loader.purs
+++ b/src/PursLoader/Loader.purs
@@ -34,6 +34,7 @@ import PursLoader.LoaderRef
   , resourcePath
   )
 
+import PursLoader.Debug (debug)
 import PursLoader.LoaderUtil (parseQuery)
 import PursLoader.Options (Options(..))
 import PursLoader.Path (dirname, relative)
@@ -47,6 +48,8 @@ loader ref source = do
 
   cacheable ref
 
+  debug "Invoke PureScript plugin compilation"
+
   pluginContext.compile (compile callback)
   where
   pluginContext :: Plugin.Context (Effects eff)
@@ -56,6 +59,8 @@ loader ref source = do
   compile callback error' { srcMap, ffiMap, graph } = do
     clearDependencies ref
 
+    either (const $ pure unit) (\a -> debug ("Adding PureScript dependency " ++ a)) name
+
     addDependency ref (resourcePath ref)
 
     either (\err -> callback (Just err) "") id
@@ -63,6 +68,7 @@ loader ref source = do
     where
     handle :: String -> Array String -> String -> Eff (Effects eff) Unit
     handle name' deps res = do
+      debug ("Adding PureScript transitive dependencies for " ++ name')
       addTransitive name'
       foreachE deps addTransitive
       callback (toMaybe error') res