1 files changed, 53 insertions, 0 deletions
diff --git a/stdlib/source/lux/platform/compiler/meta/cache/dependency.lux b/stdlib/source/lux/platform/compiler/meta/cache/dependency.lux
new file mode 100644
index 000000000..e63fa192b
--- /dev/null
+++ b/stdlib/source/lux/platform/compiler/meta/cache/dependency.lux
@@ -0,0 +1,53 @@
+(.module:
+  [lux (#- Module)
+   [data
+    ["." text]
+    [collection
+     [list ("list/." Functor<List> Fold<List>)]
+     ["dict" dictionary (#+ Dictionary)]]]]
+  [///io (#+ Module)]
+  [///archive (#+ Archive)])
+
+(type: #export Graph (Dictionary Module (List Module)))
+
+(def: #export empty Graph (dict.new text.Hash<Text>))
+
+(def: #export (add to from)
+  (-> Module Module Graph Graph)
+  (|>> (dict.update~ from (list) (|>> (#.Cons to)))
+       (dict.update~ to (list) id)))
+
+(def: dependents
+  (-> Module Graph (Maybe (List Text)))
+  dict.get)
+
+(def: #export (remove module dependency)
+  (-> Module Graph Graph)
+  (case (dependents module dependency)
+    (#.Some dependents)
+    (list/fold remove (dict.remove module dependency) dependents)
+
+    #.None
+    dependency))
+
+(type: #export Dependency
+  {#module Module
+   #imports (List Module)})
+
+(def: #export (dependency [module imports])
+  (-> Dependency Graph)
+  (list/fold (..add module) ..empty imports))
+
+(def: #export graph
+  (-> (List Dependency) Graph)
+  (|>> (list/map ..dependency)
+       (list/fold dict.merge empty)))
+
+(def: #export (prune archive graph)
+  (-> Archive Graph Graph)
+  (list/fold (function (_ module graph)
+               (if (dict.contains? module archive)
+                 graph
+                 (..remove module graph)))
+             graph
+             (dict.keys graph)))