format

.ocamlformat

@@ -0,0 +1,15 @@
+version = 0.24.1
+profile=conventional
+margin=80
+if-then-else=k-r
+parens-ite=true
+parens-tuple=multi-line-only
+sequence-style=terminator
+type-decl=sparse
+break-cases=toplevel
+cases-exp-indent=2
+field-space=tight-decl
+leading-nested-match-parens=true
+module-item-spacing=compact
+quiet=true
+ocaml-version=4.08.0

dune

@@ -1,4 +1,3 @@
-
 (mdx
  (package printbox-html)
  (libraries printbox printbox-text printbox-html)

examples/lambda.ml

@@ -1,7 +1,5 @@
-
 (** Example of printing trees: lambda-term evaluation *)
 
-
 type term =
   | Lambda of string * term
   | App of term * term
@@ -14,92 +12,99 @@ let _gensym =
     incr r;
     s
 
-module SSet = Set.Make(String)
-module SMap = Map.Make(String)
+module SSet = Set.Make (String)
+module SMap = Map.Make (String)
 
-let rec fvars t = match t with
+let rec fvars t =
+  match t with
   | Var s -> SSet.singleton s
-  | Lambda (v,t') ->
-      let set' = fvars t' in
-      SSet.remove v set'
+  | Lambda (v, t') ->
+    let set' = fvars t' in
+    SSet.remove v set'
   | App (t1, t2) -> SSet.union (fvars t1) (fvars t2)
 
 (* replace [var] with the term [by] *)
-let rec replace t ~var ~by = match t with
-  | Var s -> if s=var then by else t
-  | App (t1,t2) -> App (replace t1 ~var ~by, replace t2 ~var ~by)
-  | Lambda (v, _t') when v=var -> t  (* no risk *)
+let rec replace t ~var ~by =
+  match t with
+  | Var s ->
+    if s = var then
+      by
+    else
+      t
+  | App (t1, t2) -> App (replace t1 ~var ~by, replace t2 ~var ~by)
+  | Lambda (v, _t') when v = var -> t (* no risk *)
   | Lambda (v, t') -> Lambda (v, replace t' ~var ~by)
 
 (* rename [t] so that [var] doesn't occur in it *)
 let rename ~var t =
-  if SSet.mem var (fvars t)
-    then replace t ~var ~by:(Var (_gensym ()))
-    else t
+  if SSet.mem var (fvars t) then
+    replace t ~var ~by:(Var (_gensym ()))
+  else
+    t
 
-let (>>=) o f = match o with
+let ( >>= ) o f =
+  match o with
   | None -> None
   | Some x -> f x
 
-let rec one_step t = match t with
+let rec one_step t =
+  match t with
   | App (Lambda (var, t1), t2) ->
-      let t2' = rename ~var t2 in
-      Some (replace t1 ~var ~by:t2')
+    let t2' = rename ~var t2 in
+    Some (replace t1 ~var ~by:t2')
   | App (t1, t2) ->
-      begin match one_step t1 with
-      | None ->
-          one_step t2 >>= fun t2' ->
-          Some (App (t1,t2'))
-      | Some t1' ->
-          Some (App (t1',t2))
-      end
+    (match one_step t1 with
+    | None -> one_step t2 >>= fun t2' -> Some (App (t1, t2'))
+    | Some t1' -> Some (App (t1', t2)))
   | Var _ -> None
-  | Lambda (v,t') ->
-      one_step t' >>= fun t'' ->
-      Some (Lambda (v, t''))
+  | Lambda (v, t') -> one_step t' >>= fun t'' -> Some (Lambda (v, t''))
 
 let normal_form t =
-  let rec aux acc t = match one_step t with
-    | None -> List.rev (t::acc)
-    | Some t' -> aux (t::acc) t'
+  let rec aux acc t =
+    match one_step t with
+    | None -> List.rev (t :: acc)
+    | Some t' -> aux (t :: acc) t'
   in
   aux [] t
 
 let _split_fuel f =
-  assert (f>=2);
-  if f=2 then 1,1
-  else
-    let x = 1+Random.int (f-1) in
-    f-x, x
+  assert (f >= 2);
+  if f = 2 then
+    1, 1
+  else (
+    let x = 1 + Random.int (f - 1) in
+    f - x, x
+  )
 
 let _random_var () =
   let v = [| "x"; "y"; "z"; "u"; "w" |] in
   v.(Random.int (Array.length v))
 
-let  _choose_var ~vars = match vars with
+let _choose_var ~vars =
+  match vars with
   | [] -> Var (_random_var ())
-  | _::_ ->
-      let i = Random.int (List.length vars) in
-      List.nth vars i
+  | _ :: _ ->
+    let i = Random.int (List.length vars) in
+    List.nth vars i
 
 let rec _random_term fuel vars =
   match Random.int 2 with
   | _ when fuel = 1 -> _choose_var ~vars
   | 0 ->
-      let f1,f2 = _split_fuel fuel in
-      App (_random_term f1 vars, _random_term f2 vars)
+    let f1, f2 = _split_fuel fuel in
+    App (_random_term f1 vars, _random_term f2 vars)
   | 1 ->
-      let v = _random_var () in
-      Lambda (v, _random_term (fuel-1) (Var v::vars))
+    let v = _random_var () in
+    Lambda (v, _random_term (fuel - 1) (Var v :: vars))
   | _ -> assert false
 
 let print_term t =
   PrintBox.mk_tree
     (function
       | Var v -> PrintBox.line v, []
-      | App (t1,t2) -> PrintBox.line "app", [t1;t2]
-      | Lambda (v,t') -> PrintBox.line "lambda", [Var v; t']
-    ) t
+      | App (t1, t2) -> PrintBox.line "app", [ t1; t2 ]
+      | Lambda (v, t') -> PrintBox.line "lambda", [ Var v; t' ])
+    t
 
 let print_reduction t =
   let l = normal_form t in