Intial exploration of JSX ast

Map child expressions

Initial mapping of Pexp_jsx_fragment to 0

Correct location in mapping

Update analysis for jsx_fragment

Remove unused code

Print something for ml print

Commit invalid test results for reference

Try improve printing

Correct fragment range, try and print comments

Indent jsx

Process comments from children inside fragment

Attach comments to fragment tags

Fix comment

Improve comment formatting

Print single element on same line

Update comment

WIP: Debug

More debugging

Works

Fix some jsx printing

Fix the test

Clean up

Update tests with location changes

Author: nojaf

analysis/src/CompletionFrontEnd.ml

@@ -1232,7 +1232,8 @@ let completionWithParser1 ~currentFile ~debug ~offset ~path ~posCursor
                          then ValueOrField
                          else Value);
                     }))
-        | Pexp_construct ({txt = Lident ("::" | "()")}, _) ->
+        | Pexp_construct ({txt = Lident ("::" | "()")}, _) | Pexp_jsx_fragment _
+          ->
           (* Ignore list expressions, used in JSX, unit, and more *) ()
         | Pexp_construct (lid, eOpt) -> (
           let lidPath = flattenLidCheckDot lid in

analysis/src/Utils.ml

@@ -111,6 +111,7 @@ let identifyPexp pexp =
   | Pexp_pack _ -> "Pexp_pack"
   | Pexp_extension _ -> "Pexp_extension"
   | Pexp_open _ -> "Pexp_open"
+  | Pexp_jsx_fragment _ -> "Pexp_jsx_fragment"
 
 let identifyPpat pat =
   match pat with
@@ -154,6 +155,10 @@ let isJsxComponent (vb : Parsetree.value_binding) =
   |> List.exists (function
        | {Location.txt = "react.component" | "jsx.component"}, _payload -> true
        | _ -> false)
+  ||
+  match vb.pvb_expr.pexp_desc with
+  | Parsetree.Pexp_jsx_fragment _ -> true
+  | _ -> false
 
 let checkName name ~prefix ~exact =
   if exact then name = prefix else startsWith name prefix

compiler/frontend/bs_ast_mapper.ml

@@ -366,6 +366,8 @@ module E = struct
     | Pexp_open (ovf, lid, e) ->
       open_ ~loc ~attrs ovf (map_loc sub lid) (sub.expr sub e)
     | Pexp_extension x -> extension ~loc ~attrs (sub.extension sub x)
+    | Pexp_jsx_fragment (o, xs, c) ->
+      jsx_fragment o (List.map (sub.expr sub) xs) c
 end
 
 module P = struct

compiler/ml/ast_helper.ml

@@ -180,8 +180,35 @@ module Exp = struct
   let pack ?loc ?attrs a = mk ?loc ?attrs (Pexp_pack a)
   let open_ ?loc ?attrs a b c = mk ?loc ?attrs (Pexp_open (a, b, c))
   let extension ?loc ?attrs a = mk ?loc ?attrs (Pexp_extension a)
+  let jsx_fragment ?loc ?attrs a b c =
+    mk ?loc ?attrs (Pexp_jsx_fragment (a, b, c))
 
   let case lhs ?guard rhs = {pc_lhs = lhs; pc_guard = guard; pc_rhs = rhs}
+
+  let make_list_expression loc seq ext_opt =
+    let rec handle_seq = function
+      | [] -> (
+        match ext_opt with
+        | Some ext -> ext
+        | None ->
+          let loc = {loc with Location.loc_ghost = true} in
+          let nil = Location.mkloc (Longident.Lident "[]") loc in
+          construct ~loc nil None)
+      | e1 :: el ->
+        let exp_el = handle_seq el in
+        let loc =
+          Location.
+            {
+              loc_start = e1.Parsetree.pexp_loc.Location.loc_start;
+              loc_end = exp_el.pexp_loc.loc_end;
+              loc_ghost = false;
+            }
+        in
+        let arg = tuple ~loc [e1; exp_el] in
+        construct ~loc (Location.mkloc (Longident.Lident "::") loc) (Some arg)
+    in
+    let expr = handle_seq seq in
+    {expr with pexp_loc = loc}
 end
 
 module Mty = struct

compiler/ml/ast_helper.mli

@@ -208,8 +208,18 @@ module Exp : sig
   val open_ :
     ?loc:loc -> ?attrs:attrs -> override_flag -> lid -> expression -> expression
   val extension : ?loc:loc -> ?attrs:attrs -> extension -> expression
+  val jsx_fragment :
+    ?loc:loc ->
+    ?attrs:attrs ->
+    Lexing.position ->
+    expression list ->
+    Lexing.position ->
+    expression
 
   val case : pattern -> ?guard:expression -> expression -> case
+
+  val make_list_expression :
+    Location.t -> expression list -> expression option -> expression
 end
 
 (** Value declarations *)

compiler/ml/ast_iterator.ml

@@ -344,6 +344,7 @@ module E = struct
       iter_loc sub lid;
       sub.expr sub e
     | Pexp_extension x -> sub.extension sub x
+    | Pexp_jsx_fragment (_, xs, _) -> List.iter (sub.expr sub) xs
 end
 
 module P = struct

compiler/ml/ast_mapper.ml

@@ -329,6 +329,8 @@ module E = struct
     | Pexp_open (ovf, lid, e) ->
       open_ ~loc ~attrs ovf (map_loc sub lid) (sub.expr sub e)
     | Pexp_extension x -> extension ~loc ~attrs (sub.extension sub x)
+    | Pexp_jsx_fragment (o, xs, c) ->
+      jsx_fragment ~loc ~attrs o (List.map (sub.expr sub) xs) c
 end
 
 module P = struct

compiler/ml/ast_mapper_to0.ml

@@ -407,6 +407,18 @@ module E = struct
     | Pexp_open (ovf, lid, e) ->
       open_ ~loc ~attrs ovf (map_loc sub lid) (sub.expr sub e)
     | Pexp_extension x -> extension ~loc ~attrs (sub.extension sub x)
+    | Pexp_jsx_fragment (o, xs, c) ->
+      (*
+         The location of  Pexp_jsx_fragment is from the start of < till the end of />.
+         This is not the case in the old AST. There it is from >...</
+      *)
+      let loc = {loc with loc_start = o; loc_end = c} in
+      let list_expr = Ast_helper.Exp.make_list_expression loc xs None in
+      let mapped = sub.expr sub list_expr in
+      let jsx_attr =
+        sub.attribute sub (Location.mknoloc "JSX", Parsetree.PStr [])
+      in
+      {mapped with pexp_attributes = jsx_attr :: attrs}
 end
 
 module P = struct

compiler/ml/depend.ml

@@ -289,6 +289,7 @@ let rec add_expr bv exp =
     | Pstr_eval ({pexp_desc = Pexp_construct (c, None)}, _) -> add bv c
     | _ -> handle_extension e)
   | Pexp_extension e -> handle_extension e
+  | Pexp_jsx_fragment (_, xs, _) -> List.iter (add_expr bv) xs
 
 and add_cases bv cases = List.iter (add_case bv) cases
 

compiler/ml/parsetree.ml

@@ -313,8 +313,14 @@ and expression_desc =
        let open M in E
        let! open M in E *)
   | Pexp_extension of extension
-(* [%id] *)
-(* . *)
+  (* [%id] *)
+  (* . *)
+  (* represents <> foo </> , the entire range is stored in the expression , we keep track of >, children and </ *)
+  | Pexp_jsx_fragment of
+      (* > *) Lexing.position
+      * (* children *)
+      expression list
+      * (* </ *) Lexing.position
 
 and case = {
   (* (P -> E) or (P when E0 -> E) *)