progress with conversion functionality

dotscape.mlb

@@ -73,4 +73,6 @@ imperative-shell/file-thread.sml
 imperative-shell/draw-thread.sml
 imperative-shell/init-glfw.sml
 
+imperative-shell/converter.sml
+
 imperative-shell/shell.sml

imperative-shell/converter.sml

@@ -0,0 +1,45 @@
+structure Converter =
+struct
+  fun endsWithDsc str =
+    if String.size str >= 4 then
+      let
+        val size = String.size str
+        val expectedExtension = String.substring (str, size - 4, 4)
+      in
+        expectedExtension = ".dsc"
+      end
+    else
+      false
+
+  fun convertFile path = ()
+
+  fun loop (dir, rootPath) =
+    case OS.FileSys.readDir dir of
+      SOME path =>
+        let
+          val folderPath = String.concat [rootPath, "/", path]
+        in
+          if OS.FileSys.isDir folderPath then
+            (* handle folder *)
+            let val newDir = OS.fileSys.openDir folderPath
+            in loop (newDir, folderPath)
+            end
+          else if OS.FileSys.isLink folderPath then
+            (* continue looping and ignore *)
+            loop (dir, rootPath)
+          else
+            (* handle file, if file has ".dsc" at the end *)
+            let val () = if endsWithDsc path then convertFile folderPath else ()
+            in loop (dir, rootPath)
+            end
+        end
+    | NONE => OS.FileSys.closeDir dir
+
+  fun main () =
+    let
+      val path = OS.FileSys.getDir ()
+      val dir = OS.FileSys.openDir path
+    in
+      loop (dir, path)
+    end
+end

imperative-shell/shell.sml

@@ -2,7 +2,7 @@ structure Shell =
 struct
   fun main () =
     case CommandLine.arguments () of
-      ["-r"] => (print "todo: convert dsc files to sml file\n")
+      ["-r"] => Converter.main ()
     | [] => InitGlfw.main ()
     | args =>
         let