feat(Logger): debugging interface

src/Logger.ml

@@ -0,0 +1,25 @@
+include LoggerSigs
+
+module Make () = struct
+  type 'a Effect.t +=
+    | Debug : Diagnostic.loctext -> unit Effect.t
+    | CallBegin : Diagnostic.loctext -> unit Effect.t
+    | CallEnd : Diagnostic.loctext -> unit Effect.t
+
+  let emit_loctext t = Effect.perform @@ Debug t
+  let emit ?loc s = emit_loctext @@ Diagnostic.loctext ?loc s
+  let emitf ?loc = Diagnostic.kloctextf ?loc emit_loctext
+
+  let trace_open_loctext t = Effect.perform @@ CallBegin t
+  let trace_close_loctext t = Effect.perform @@ CallEnd t
+
+  let trace ?loc s f =
+    trace_open_loctext (Diagnostic.loctext ?loc s);
+    Fun.protect f
+      ~finally:(fun () -> trace_close_loctext (Diagnostic.loctext ?loc s))
+  let tracef ?loc =
+    Diagnostic.ktextf @@ fun t f ->
+    trace_open_loctext {Range.value = t; loc};
+    Fun.protect f
+      ~finally:(fun () -> trace_close_loctext {Range.value = t; loc})
+end

src/Logger.mli

@@ -0,0 +1,3 @@
+include module type of LoggerSigs
+
+module Make () : S

src/LoggerSigs.ml

@@ -0,0 +1,7 @@
+module type S =
+sig
+  val emit : ?loc:Range.t -> string -> unit
+  val emitf : ?loc:Range.t -> ('a, Format.formatter, unit, unit) format4 -> 'a
+  val trace : ?loc:Range.t -> string -> (unit -> 'a) -> 'a
+  val tracef : ?loc:Range.t -> ('b, Format.formatter, unit, (unit -> 'a) -> 'a) format4 -> 'b
+end