Script to redeploy testlib.sml to all exercises on changes.

Makefile

@@ -15,4 +15,7 @@ test-%:
 	@cd ./exercises/practice/$(exercise) && cat test.sml | sed 's/$(exercise).sml/.meta\/example.sml/' | poly -q
 	@echo
 
-.PHONY: test
+redeploy-testlib:
+	poly --script sml-bin/redeploy-testlib.sml
+
+.PHONY: test redeploy-testlib

README.md

@@ -30,7 +30,11 @@ Every exercise must have at least these files:
 
 ### `testlib.sml`
 
-This helper has this structures:
+The copy of `testlib.sml` for each exercise should be in sync with `lib/testlib.sml`.
+`make redeploy-testlib` is provided for syncing all exercises with `lib/testlib.sml`
+when it is updated.
+
+This helper has these structures:
 
 ```sml
 structure Expect:

sml-bin/redeploy-testlib.sml

@@ -0,0 +1,49 @@
+structure Path =  OS.Path
+structure File =  OS.FileSys
+
+fun printLn x = print (x ^ "\n")
+
+fun fileExists x = File.access (x,[])
+
+fun testLibName base slug =
+  Path.joinDirFile
+    {
+      dir = Path.concat (base,slug),
+      file = "testlib.sml"
+    }
+
+fun dirList dirname =
+  let
+    fun go d xs =
+      case File.readDir d of
+          SOME x => go d (x::xs)
+        | NONE   => (File.closeDir d; xs)
+  in
+    go (File.openDir dirname) []
+  end
+
+fun fileBytes path =
+  let
+    val instream = BinIO.openIn path
+    val bytes = BinIO.inputAll instream
+  in
+    BinIO.closeIn instream; bytes
+  end
+
+fun writeFileBytes bytes path =
+  let
+    val out = BinIO.openOut path
+  in
+    BinIO.output (out,bytes);
+    BinIO.closeOut out
+  end
+
+fun relUnixPathToAbs x = Path.concat (File.getDir (), Path.fromUnixPath x)
+
+val _ =
+  let
+    val practice = relUnixPathToAbs "exercises/practice"
+    val testLib = fileBytes "lib/testlib.sml"
+  in
+    List.app (writeFileBytes testLib o testLibName practice) (dirList practice)
+  end