feat: mk_all script implemented in Lean

scripts/mkAll.lean

@@ -0,0 +1,45 @@
+/-
+Copyright (c) 2024 Damiano Testa. All rights reserved.
+Released under Apache 2.0 license as described in the file LICENSE.
+Authors: Damiano Testa
+-/
+import Lean.Util.Path
+
+/-!
+#  An implementation of the `mk_all.sh` script in Lean
+-/
+
+namespace Mathlib.mkAll
+
+/-- the command `git ls-files '*.lean'` -/
+def gitLSFiles : IO.Process.SpawnArgs where
+  cmd := "git"
+  args := #["ls-files", "*.lean"]
+
+open Lean System.FilePath in
+/-- `getAll str` takes all Git-managed `.lean` files in the repository in the dir `str` and
+returns the string
+```
+import file₁
+...
+import fileₙ
+```
+The string `str` is optional and the stript defaults to `Mathlib` if unprovided. -/
+def getAll (ml : String := "Mathlib") : IO String := do
+  let ml.lean := addExtension ⟨ml⟩ "lean"  -- `Mathlib.lean`
+  let mlDir := ml.push pathSeparator       -- `Mathlib/`
+  let allLean ← IO.Process.run gitLSFiles
+  let files : List System.FilePath := ((allLean.splitOn "\n").filter mlDir.isPrefixOf).map (⟨·⟩)
+  let files := (files.erase ml.lean).toArray.qsort (·.toString < ·.toString)
+  let withImport ← files.mapM fun f => return "import " ++ (← moduleNameOfFileName f none).toString
+  return ("\n".intercalate withImport.toList).push '\n'
+
+/-- the "Mathlib usual suspects" for "import all" files. -/
+abbrev candidates := #["Mathlib", "MathlibExtras", "Mathlib/Tactic", "Counterexamples", "Archive"]
+
+open System.FilePath in
+/-- running `#eval mkAll arr` creates an "import all" file for each of the roots in the array `arr`.
+The input `arr` is optional and `mkAll` defaults to using `candidates`, if unprovided. -/
+def mkAll (cands : Array String := candidates) : IO Unit := do
+  for d in cands do
+    IO.FS.writeFile (addExtension ⟨d⟩ "lean") (← getAll d)