Start 'Std' module, move Common over

src/common/Files.ml

@@ -1,4 +1,4 @@
-open Core
+open Std
 
 let stanfunctions_suffix = ".stanfunctions"
 
@@ -8,4 +8,4 @@ let remove_dotstan s =
     (String.chop_suffix ~suffix:".stan" s)
   |> Option.value ~default:s
 
-let is_stanfunctions = String.is_suffix ~suffix:stanfunctions_suffix
+let is_stanfunctions = String.ends_with ~suffix:stanfunctions_suffix

src/common/dune

@@ -1,6 +1,6 @@
 (library
  (name common)
  (public_name stanc.common)
- (libraries core fmt)
+ (libraries std fmt)
  (instrumentation
   (backend bisect_ppx)))

src/frontend/Semantic_error.ml

@@ -14,7 +14,7 @@ let quoted = SignatureMismatch.quoted
 let found_type ppf =
   Fmt.pf ppf "@ Instead found type %a." (actual_style UnsizedType.pp)
 
-let rec expected_types : UnsizedType.t Common.Nonempty_list.t Fmt.t =
+let rec expected_types : UnsizedType.t Std.Nonempty_list.t Fmt.t =
   let ust = expected_style UnsizedType.pp in
   fun ppf l ->
     match l with
@@ -23,7 +23,7 @@ let rec expected_types : UnsizedType.t Common.Nonempty_list.t Fmt.t =
     | [t1; t2; t3] -> Fmt.pf ppf "%a,@ %a,@ or %a" ust t1 ust t2 ust t3
     | t :: ts ->
         Fmt.pf ppf "%a,@ %a" ust t expected_types
-          (ts |> Common.Nonempty_list.of_list_exn)
+          (ts |> Std.Nonempty_list.of_list_exn)
 
 module TypeError = struct
   type t =
@@ -138,7 +138,7 @@ module TypeError = struct
       quoted name name pp_lik_args ellipsis ellipsis pp_laplace_tols
       pp_supplied_tys info ()
 
-  let rec expected_types : UnsizedType.t Common.Nonempty_list.t Fmt.t =
+  let rec expected_types : UnsizedType.t Std.Nonempty_list.t Fmt.t =
     let ust = expected_style UnsizedType.pp in
     fun ppf l ->
       match l with
@@ -147,7 +147,7 @@ module TypeError = struct
       | [t1; t2; t3] -> Fmt.pf ppf "%a,@ %a,@ or %a" ust t1 ust t2 ust t3
       | t :: ts ->
           Fmt.pf ppf "%a,@ %a" ust t expected_types
-            (ts |> Common.Nonempty_list.of_list_exn)
+            (ts |> Std.Nonempty_list.of_list_exn)
 
   let pp ppf = function
     | IncorrectReturnType (t1, t2) ->
@@ -210,7 +210,7 @@ module TypeError = struct
         Fmt.pf ppf "The inner type in reduce_sum array must be %a.%a"
           expected_types
           (Stan_math_signatures.reduce_sum_slice_types
-         |> Common.Nonempty_list.of_list_exn)
+         |> Std.Nonempty_list.of_list_exn)
           found_type ty
     | IllTypedReduceSum (name, arg_tys, expected_args, error, _callback_location)
       ->
@@ -764,7 +764,7 @@ module StatementError = struct
           lt.type_ found_type rt.type_
     | IllTypedAssignment (op, lt, rt) ->
         let pp_expected_types ppf signatures =
-          match Common.Nonempty_list.of_list signatures with
+          match Std.Nonempty_list.of_list signatures with
           | None ->
               Fmt.pf ppf
                 "There are no valid right hand sides for the given left hand \

src/frontend/Typechecker.ml

@@ -280,7 +280,7 @@ let check_id cf tenv id =
   let loc = id.id_loc in
   let (value :: _) =
     Env.find tenv (Utils.stdlib_distribution_name id.name)
-    |> Common.Nonempty_list.of_list
+    |> Std.Nonempty_list.of_list
     |> Option.value_or_thunk ~default:(fun () ->
         Semantic_error.ident_not_in_scope loc id.name
           (Env.nearest_ident tenv id.name)

src/common/Nonempty_list.ml → src/std/Nonempty_list.ml

@@ -5,6 +5,5 @@ let of_list : _ list -> _ t option = function
   | hd :: tl -> Some (hd :: tl)
 
 let of_list_exn : _ list -> _ t = function
-  | [] ->
-      ICE.internal_error "Nonempty_list.of_list_exn: empty list" [@coverage off]
+  | [] -> raise (Invalid_argument "Nonempty_list.of_list_exn: empty list")
   | hd :: tl -> hd :: tl

src/std/dune

@@ -0,0 +1,6 @@
+(library
+ (name std)
+ (public_name stanc.std)
+ (libraries sexplib0)
+ (instrumentation
+  (backend bisect_ppx)))

src/std/std.ml

@@ -0,0 +1,26 @@
+(** Extensions to the standard library. Most files in the project should begin
+    [open Std]. *)
+
+(** New modules *)
+
+module Nonempty_list = Nonempty_list
+
+(** OCaml Stdlib with labeled functions *)
+
+include StdLabels
+include MoreLabels
+
+(** A few extensions to builtin modules *)
+
+module Option = struct
+  include Option
+
+  let first_some a b = Option.blend Fun.const a b
+end
+
+module String = struct
+  include String
+
+  let chop_suffix ~suffix s =
+    if ends_with ~suffix s then Some (drop_last (length suffix) s) else None
+end