Small ocaml/js output rehaul (#582)

2024-09-19 16:28:12 +03:00 · 2024-02-22 12:15:31 +01:00 · 2024-02-22 12:15:31 +01:00 · c78a6b62c9
commit c78a6b62c9
parent 4ee4992b54 cafad727fe
11 changed files with 259 additions and 175 deletions
--- a/INSTALL.md
+++ b/INSTALL.md
@ -137,19 +137,17 @@ To uninstall, use
 #### Updating [`@catala-lang/catala-web-assets`](https://www.npmjs.com/package/@catala-lang/catala-web-assets) 

 The Catala website features assets generated by the Catala compiler. They are
-needed to build the website. To produce them, simply run
+needed to build the website. To produce them, run

-    make website-assets DUNE_PROFILE=release
+    make website-assets.tar

-Then, use a helper script to copy them over to the `assets` directory of the
-[`catala-web-assets`](https://github.com/CatalaLang/catala-web-assets)
-repository.
+Then, get the base [`catala-web-assets`](https://github.com/CatalaLang/catala-web-assets)
+repository, and untar the generated file within the `assets/` subdirectory:

-    ./generate_website_assets.sh <path-to-catala-web-assets>/assets
+     tar xf website-assets.tar -C <path-to-catala-web-assets>/assets

 > You will need the `groff` executable to generate the HTML versions of the man
-pages, as well as the `rsync` executable to transfer files (preferred to `cp`)
-because it also works with a remote server.
+pages.

 ## Syntax highlighting

--- a/65
+++ b/65
@ -217,15 +217,27 @@ tests/%: .FORCE
 # (and therefore the doc target here)
 WEBSITE_ASSETS = grammar.html catala.html clerk.html

-$(addprefix _build/default/,$(WEBSITE_ASSETS)):
-	dune build $@
+WEBSITE_ASSETS_EXAMPLES = \
+  tutorial_en/tutorial_en.html \
+  tutoriel_fr/tutoriel_fr.html \
+  us_tax_code/us_tax_code.html \
+  allocations_familiales/allocations_familiales.html \
+  allocations_familiales/allocations_familiales_schema.json \
+  aides_logement/aides_logement.html \
+  aides_logement/aides_logement_schema.json
+
+WEBSITE_ASSETS_ALL = $(WEBSITE_ASSETS) $(addprefix catala-examples.tmp/,$(WEBSITE_ASSETS_EXAMPLES))

 website-assets-base: build
-	dune build $(WEBSITE_ASSETS)
+	$(call local_tmp_clone,catala-examples) && \
+	dune build $(addprefix _build/default/,$(WEBSITE_ASSETS_ALL))
+
+website-assets.tar:
+	# $(MAKE) DUNE_PROFILE=release website-assets-base
+	tar cf $@ $(foreach file,$(WEBSITE_ASSETS_ALL),-C $(CURDIR)/$(dir _build/default/$(file)) $(notdir $(file)))

 #> website-assets				: Builds all the assets necessary for the Catala website
-website-assets:
-	$(MAKE) DUNE_PROFILE=release website-assets-base
+website-assets: website-assets.tar

 ##########################################
 # Miscellaneous
@ -238,32 +250,35 @@ all: \
 	runtimes \
 	plugins

-BRANCH=$(shell git branch --show-current 2>/dev/null || echo master)
+BRANCH = $(shell git branch --show-current 2>/dev/null || echo master)
+
+# Attempt a clone of the named CatalaLang repo into <name>.tmp, using local git
+# objects in ../<name> if available, the branch with the same name as the
+# current branch if it exists (master otherwise), and falling back to a local
+# clone of ../<name> if the network is not available. The temp dir is removed
+# when the shell terminates, so this must be run in the same "Makefile line" as
+# its usage.
+local_tmp_clone = { \
+  rm -rf $1.tmp && \
+  trap "rm -rf $1.tmp" EXIT && \
+  git clone https://github.com/CatalaLang/$1 \
+    --depth 1 --reference-if-able ../$1 \
+    $1.tmp -b $(BRANCH) || \
+  git clone https://github.com/CatalaLang/$1 \
+    --depth 1 --reference-if-able ../$1 \
+    $1.tmp || \
+  git clone -s ../$1 $1.tmp $(BRANCH) || \
+  git clone -s ../$1 $1.tmp master; \
+}

 #> alltest					: Runs more extensive tests, including the examples and french-law. Use before push!
 alltest: dependencies-python
 	@export DUNE_PROFILE=check && \
 	dune build @update-parser-messages @install @runtest && \
 	$(CLERK_BIN) test tests && \
-	rm -rf catala-examples.tmp french-law.tmp && \
-	trap "rm -rf catala-examples.tmp french-law.tmp $$TMP" EXIT && \
-	{ git clone https://github.com/CatalaLang/catala-examples \
-	    --depth 1 --reference-if-able ../catala-examples \
-	    catala-examples.tmp -b $(BRANCH) || \
-	  git clone https://github.com/CatalaLang/catala-examples \
-	    --depth 1 --reference-if-able ../catala-examples \
-	    catala-examples.tmp || \
-	  git clone -s ../catala-examples catala-examples.tmp $(BRANCH) || \
-	  git clone -s ../catala-examples catala-examples.tmp master; } && \
+	$(call local_tmp_clone,catala-examples) && \
 	$(CLERK_BIN) test catala-examples.tmp && \
-	{ git clone https://github.com/CatalaLang/french-law \
-	    --depth 1 --reference-if-able ../french-law \
-	    french-law.tmp -b $(BRANCH) || \
-	  git clone https://github.com/CatalaLang/french-law \
-	    --depth 1 --reference-if-able ../french-law \
-	    french-law.tmp || \
-	  git clone -s ../french-law french-law.tmp $(BRANCH) || \
-	  git clone -s ../french-law french-law.tmp master; } && \
+	$(call local_tmp_clone,french-law) && \
 	make -C french-law.tmp all PY_VENV_DIR=$(ROOT_DIR)/_python_venv

 #> clean					: Clean build artifacts
@ -288,4 +303,4 @@ help_catala:
 .PHONY: inspect clean all english allocations_familiales	\
 	pygments install build_dev build doc format dependencies		\
 	dependencies-ocaml catala.html help parser-messages plugins		\
-	website-assets website-assets-base
+	website-assets.tar website-assets-base
--- a/build_system/clerk_driver.ml
+++ b/build_system/clerk_driver.ml
@ -347,9 +347,7 @@ module Poll = struct

  let ocaml_link_flags : string list Lazy.t =
    lazy
-      (let link_libs =
-         ["yojson"; "ppx_yojson_conv_lib"; "zarith"; "dates_calc"]
-       in
+      (let link_libs = ["zarith"; "dates_calc"] in
       let link_libs_flags =
         List.concat_map
           (fun lib ->
@ -493,6 +491,10 @@ let[@ocamlformat "disable"] static_base_rules =
      ]
      ~description:["<ocaml>"; "⇒"; !output];

+    Nj.rule "python"
+      ~command:[!catala_exe; "python"; !catala_flags; !input; "-o"; !output]
+      ~description:["<catala>"; "python"; "⇒"; !output];
+
    Nj.rule "out-test"
      ~command: [
        !catala_exe; !test_command; "--plugin-dir="; "-o -"; !catala_flags; !input;
@ -591,21 +593,30 @@ let gen_build_statements
          ~outputs:[modd m])
      item.module_def
  in
-  let ml_file =
+  let target_file ext =
    match item.module_def with
-    | Some m -> (!Var.builddir / src /../ m) ^ ".ml"
-    | None -> (!Var.builddir / !Var.src) ^ ".ml"
+    | Some m -> (!Var.builddir / src /../ m) ^ "." ^ ext
+    | None -> (!Var.builddir / !Var.src) ^ "." ^ ext
  in
-  let ocaml =
+  let ml_file = target_file "ml" in
+  let py_file = target_file "py" in
+  let ocaml, python =
    if item.extrnal then
-      Nj.build "copy"
-        ~implicit_in:[inc srcv]
-        ~inputs:[src -.- "ml"]
-        ~outputs:[ml_file]
+      ( Nj.build "copy"
+          ~implicit_in:[inc srcv]
+          ~inputs:[src -.- "ml"]
+          ~outputs:[ml_file],
+        Nj.build "copy"
+          ~implicit_in:[inc srcv]
+          ~inputs:[src -.- "py"]
+          ~outputs:[py_file] )
    else
-      Nj.build "catala-ocaml"
-        ~inputs:[inc srcv]
-        ~implicit_in:[!Var.catala_exe] ~outputs:[ml_file]
+      ( Nj.build "catala-ocaml"
+          ~inputs:[inc srcv]
+          ~implicit_in:[!Var.catala_exe] ~outputs:[ml_file],
+        Nj.build "python"
+          ~inputs:[inc srcv]
+          ~implicit_in:[!Var.catala_exe] ~outputs:[py_file] )
  in
  let ocamlopt =
    let implicit_out_exts = ["cmi"; "cmx"; "cmt"; "o"] in
@ -774,6 +785,7 @@ let gen_build_statements
         Option.to_seq expose_module;
         Seq.return ocaml;
         Seq.return ocamlopt;
+         Seq.return python;
         List.to_seq tests;
         Seq.return interpret;
       ]
--- a/catala.opam
+++ b/catala.opam
@ -31,8 +31,6 @@ depends: [
  "ocaml" {>= "4.14.0"}
  "ocamlfind" {!= "1.9.5"}
  "ocamlgraph" {>= "1.8.8"}
-  "yojson" {>= "2.0" }
-  "ppx_yojson_conv" {>= "0.14.0"}
  "re" {>= "1.9.0"}
  "sedlex" {>= "2.4"}
  "uutf" {>= "1.0.3"}
--- a/compiler/lcalc/to_ocaml.ml
+++ b/compiler/lcalc/to_ocaml.ml
@ -462,7 +462,7 @@ let format_struct_embedding
      format_struct_name struct_name format_to_module_name (`Sname struct_name)
  else
    Format.fprintf fmt
-      "@[<hov 2>let embed_%a (x: %a.t) : runtime_value =@ Struct([\"%a\"],@ \
+      "@[<hov 2>let embed_%a (x: %a.t) : runtime_value =@ Struct(\"%a\",@ \
       @[<hov 2>[%a]@])@]@\n\
       @\n"
      format_struct_name struct_name format_to_module_name (`Sname struct_name)
@ -485,7 +485,7 @@ let format_enum_embedding
  else
    Format.fprintf fmt
      "@[<hv 2>@[<hov 2>let embed_%a@ @[<hov 2>(x:@ %a.t)@]@ : runtime_value \
-       =@]@ Enum([\"%a\"],@ @[<hov 2>match x with@ %a@])@]@\n\
+       =@]@ Enum(\"%a\",@ @[<hov 2>match x with@ %a@])@]@\n\
       @\n"
      format_enum_name enum_name format_to_module_name (`Ename enum_name)
      EnumName.format enum_name
--- a/compiler/shared_ast/interpreter.ml
+++ b/compiler/shared_ast/interpreter.ml
@ -994,7 +994,7 @@ let interpret_program_dcalc p s : (Uid.MarkedString.info * ('a, 'm) gexpr) list
               built-in interpreter does not have a way to retrieve input \
               values from the command line, so it cannot execute this scope. \
               Please create another scope that provides the input arguments \
-               to this one and execute it instead. ")
+               to this one and execute it instead.")
        taus
    in
    let to_interpret =
--- a/generate_website_assets.sh
+++ b/generate_website_assets.sh
@ -1,25 +0,0 @@
-#! /usr/bin/env sh
-
-set -eux
-
-cd "$(dirname "$0")"
-
-if [ $# -ne 1 ]; then
-  echo "USAGE: \$1 DST where DST is the directory in which files have to be copied"
-  exit 1
-fi
-
-BUILD=_build/default
-
-rsync $BUILD/examples/allocations_familiales/allocations_familiales.html $1/
-rsync $BUILD/examples/aides_logement/aides_logement.html $1/
-rsync $BUILD/examples/us_tax_code/us_tax_code.html $1/
-rsync $BUILD/examples/tutorial_en/tutorial_en.html $1/
-rsync $BUILD/examples/tutoriel_fr/tutoriel_fr.html $1/
-
-rsync $BUILD/grammar.html $1/
-rsync $BUILD/catala.html $1/
-rsync $BUILD/clerk.html $1/
-
-rsync $BUILD/examples/allocations_familiales/allocations_familiales_schema.json $1/
-rsync $BUILD/examples/aides_logement/aides_logement_schema.json $1/
--- a/runtimes/jsoo/runtime.ml
+++ b/runtimes/jsoo/runtime.ml
@ -84,83 +84,75 @@ let event_manager : event_manager Js.t =
    method resetLog = Js.wrap_meth_callback R_ocaml.reset_log

    method retrieveEvents =
-      Js.wrap_meth_callback (fun () ->
-          Js.array
-            (Array.of_list
-               (R_ocaml.retrieve_log ()
-               |> R_ocaml.EventParser.parse_raw_events
-               |> List.map (fun event ->
-                      object%js
-                        val mutable data =
-                          event
-                          |> R_ocaml.yojson_of_event
-                          |> Yojson.Safe.to_string
-                          |> Js.string
-                      end))))
+      Js.wrap_meth_callback
+      @@ fun () ->
+      R_ocaml.retrieve_log ()
+      |> R_ocaml.EventParser.parse_raw_events
+      |> List.map (fun event ->
+             object%js
+               val mutable data = event |> R_ocaml.Json.event |> Js.string
+             end)
+      |> Array.of_list
+      |> Js.array

    method retrieveRawEvents =
-      Js.wrap_meth_callback (fun () ->
-          Js.array
-            (Array.of_list
-               (List.map
-                  (fun evt ->
-                    object%js
-                      val mutable eventType =
-                        Js.string
-                          (match evt with
-                          | R_ocaml.BeginCall _ -> "Begin call"
-                          | EndCall _ -> "End call"
-                          | VariableDefinition _ -> "Variable definition"
-                          | DecisionTaken _ -> "Decision taken")
+      let evt_to_js evt =
+        (* FIXME: ideally this could be just a Json.parse (R_ocaml.Json.event
+           foo) ? *)
+        object%js
+          val mutable eventType =
+            (match evt with
+            | R_ocaml.BeginCall _ -> "Begin call"
+            | EndCall _ -> "End call"
+            | VariableDefinition _ -> "Variable definition"
+            | DecisionTaken _ -> "Decision taken")
+            |> Js.string

-                      val mutable information =
-                        Js.array
-                          (Array.of_list
-                             (match evt with
-                             | BeginCall info
-                             | EndCall info
-                             | VariableDefinition (info, _, _) ->
-                               List.map Js.string info
-                             | DecisionTaken _ -> []))
+          val mutable information =
+            (match evt with
+            | BeginCall info | EndCall info | VariableDefinition (info, _, _) ->
+              List.map Js.string info
+            | DecisionTaken _ -> [])
+            |> Array.of_list
+            |> Js.array

-                      val mutable loggedIOJson =
-                        match evt with
-                        | VariableDefinition (_, io, _) ->
-                          io
-                          |> R_ocaml.yojson_of_io_log
-                          |> Yojson.Safe.to_string
-                          |> Js.string
-                        | EndCall _ | BeginCall _ | DecisionTaken _ ->
-                          "unavailable" |> Js.string
+          val mutable loggedIOJson =
+            match evt with
+            | VariableDefinition (_, io, _) ->
+              io |> R_ocaml.Json.io_log |> Js.string
+            | EndCall _ | BeginCall _ | DecisionTaken _ ->
+              "unavailable" |> Js.string

-                      val mutable loggedValueJson =
-                        (match evt with
-                        | VariableDefinition (_, _, v) -> v
-                        | EndCall _ | BeginCall _ | DecisionTaken _ ->
-                          R_ocaml.unembeddable ())
-                        |> R_ocaml.yojson_of_runtime_value
-                        |> Yojson.Safe.to_string
-                        |> Js.string
+          val mutable loggedValueJson =
+            (match evt with
+            | VariableDefinition (_, _, v) -> v
+            | EndCall _ | BeginCall _ | DecisionTaken _ ->
+              R_ocaml.unembeddable ())
+            |> R_ocaml.Json.runtime_value
+            |> Js.string

-                      val mutable sourcePosition =
-                        match evt with
-                        | DecisionTaken pos ->
-                          Js.def
-                            (object%js
-                               val mutable fileName = Js.string pos.filename
-                               val mutable startLine = pos.start_line
-                               val mutable endLine = pos.end_line
-                               val mutable startColumn = pos.start_column
-                               val mutable endColumn = pos.end_column
+          val mutable sourcePosition =
+            match evt with
+            | DecisionTaken pos ->
+              Js.def
+                (object%js
+                   val mutable fileName = Js.string pos.filename
+                   val mutable startLine = pos.start_line
+                   val mutable endLine = pos.end_line
+                   val mutable startColumn = pos.start_column
+                   val mutable endColumn = pos.end_column

-                               val mutable lawHeadings =
-                                 Js.array
-                                   (Array.of_list
-                                      (List.map Js.string pos.law_headings))
-                            end)
-                        | _ -> Js.undefined
-                    end)
-                  (R_ocaml.retrieve_log ()))))
+                   val mutable lawHeadings =
+                     List.map Js.string pos.law_headings
+                     |> Array.of_list
+                     |> Js.array
+                end)
+            | _ -> Js.undefined
+        end
+      in
+      Js.wrap_meth_callback
+      @@ fun () ->
+      R_ocaml.retrieve_log () |> List.map evt_to_js |> Array.of_list |> Js.array
  end

 let execute_or_throw_error f =
--- a/runtimes/ocaml/dune
+++ b/runtimes/ocaml/dune
@ -1,7 +1,5 @@
 (library
 (name runtime_ocaml)
 (public_name catala.runtime_ocaml)
- (preprocess
-  (pps ppx_yojson_conv))
 (libraries dates_calc zarith zarith_stubs_js)
 (modules runtime))
--- a/runtimes/ocaml/runtime.ml
+++ b/runtimes/ocaml/runtime.ml
@ -13,8 +13,6 @@
   WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
   License for the specific language governing permissions and limitations under
   the License. *)
-open Ppx_yojson_conv_lib.Yojson_conv.Primitives
-
 type nonrec unit = unit
 type nonrec bool = bool

@ -30,8 +28,8 @@ module Eoption = struct
  type 'a t = ENone of unit | ESome of 'a
 end

-type io_input = NoInput | OnlyInput | Reentrant [@@deriving yojson_of]
-type io_log = { io_input : io_input; io_output : bool } [@@deriving yojson_of]
+type io_input = NoInput | OnlyInput | Reentrant
+type io_log = { io_input : io_input; io_output : bool }

 type source_position = {
  filename : string;
@ -41,7 +39,6 @@ type source_position = {
  end_column : int;
  law_headings : string list;
 }
-[@@deriving yojson_of]

 exception EmptyError
 exception AssertionFailed of source_position
@ -190,12 +187,6 @@ let duration_to_string (d : duration) : string =
 let duration_to_years_months_days (d : duration) : int * int * int =
  Dates_calc.Dates.period_to_ymds d

-let yojson_of_money (m : money) = `Float (money_to_float m)
-let yojson_of_integer (i : integer) = `Int (integer_to_int i)
-let yojson_of_decimal (d : decimal) = `Float (decimal_to_float d)
-let yojson_of_date (d : date) = `String (date_to_string d)
-let yojson_of_duration (d : duration) = `String (duration_to_string d)
-
 type runtime_value =
  | Unit
  | Bool of bool
@ -204,11 +195,10 @@ type runtime_value =
  | Decimal of decimal
  | Date of date
  | Duration of duration
-  | Enum of string list * (string * runtime_value)
-  | Struct of string list * (string * runtime_value) list
+  | Enum of string * (string * runtime_value)
+  | Struct of string * (string * runtime_value) list
  | Array of runtime_value array
  | Unembeddable
-[@@deriving yojson_of]

 let unembeddable _ = Unembeddable
 let embed_unit () = Unit
@ -220,7 +210,7 @@ let embed_date x = Date x
 let embed_duration x = Duration x
 let embed_array f x = Array (Array.map f x)

-type information = string list [@@deriving yojson_of]
+type information = string list

 type raw_event =
  | BeginCall of information
@ -236,7 +226,6 @@ type event =
      inputs : var_def list;
      body : event list;
    }
-[@@deriving yojson_of]

 and var_def = {
  pos : source_position option;
@ -253,6 +242,108 @@ and fun_call = {
  output : var_def;
 }

+module BufferedJson = struct
+  let rec list f buf = function
+    | [] -> ()
+    | [x] -> f buf x
+    | x :: r ->
+      f buf x;
+      Buffer.add_char buf ',';
+      list f buf r
+
+  let quote buf str =
+    Buffer.add_char buf '"';
+    String.iter
+      (function
+        | ('"' | '\\') as c ->
+          Buffer.add_char buf '\\';
+          Buffer.add_char buf c
+        | '\n' -> Buffer.add_string buf "\\n"
+        | '\t' -> Buffer.add_string buf "\\t"
+        | '\r' -> Buffer.add_string buf "\\r"
+        | '\x00' .. '\x1F' as c -> Printf.bprintf buf "\\u%04x" (int_of_char c)
+        | c -> Buffer.add_char buf c)
+      str;
+    Buffer.add_char buf '"'
+
+  (* Note: the output format is made for transition with what Yojson gave us,
+     but we could change it to something nicer (e.g. objects for structures) *)
+  let rec runtime_value buf = function
+    | Unit -> Buffer.add_string buf {|"Unit"|}
+    | Bool b -> Buffer.add_string buf (string_of_bool b)
+    | Money m -> Buffer.add_string buf (money_to_string m)
+    | Integer i -> Buffer.add_string buf (integer_to_string i)
+    | Decimal d ->
+      Buffer.add_string buf (decimal_to_string ~max_prec_digits:10 d)
+    | Date d -> quote buf (date_to_string d)
+    | Duration d -> quote buf (duration_to_string d)
+    | Enum (name, (constr, v)) ->
+      Printf.bprintf buf {|[["%s"],["%s",%a]]|} name constr runtime_value v
+    | Struct (name, elts) ->
+      Printf.bprintf buf {|["%s",[%a]]|} name
+        (list (fun buf (cstr, v) ->
+             Printf.bprintf buf {|"%s":%a|} cstr runtime_value v))
+        elts
+    | Array elts ->
+      Printf.bprintf buf "[%a]" (list runtime_value) (Array.to_list elts)
+    | Unembeddable -> Buffer.add_string buf {|"unembeddable"|}
+
+  let information buf info = Printf.bprintf buf "[%a]" (list quote) info
+
+  let source_position buf pos =
+    Printf.bprintf buf {|{"filename":%a|} quote pos.filename;
+    Printf.bprintf buf {|,"start_line":%d|} pos.start_line;
+    Printf.bprintf buf {|,"start_column":%d|} pos.start_column;
+    Printf.bprintf buf {|,"end_line":%d|} pos.end_line;
+    Printf.bprintf buf {|,"end_column":%d|} pos.end_column;
+    Printf.bprintf buf {|,"law_headings":[%a]}|} (list quote) pos.law_headings
+
+  let io_input buf = function
+    | NoInput -> quote buf "NoInput"
+    | OnlyInput -> quote buf "OnlyInput"
+    | Reentrant -> quote buf "Reentrant"
+
+  let io_log buf iol =
+    Printf.bprintf buf {|{"io_input":%a|} io_input iol.io_input;
+    Printf.bprintf buf {|,"io_output":%b}|} iol.io_output
+
+  let rec event buf = function
+    | VarComputation vd ->
+      Printf.bprintf buf {|"VarComputation",%a]|} var_def vd
+    | FunCall fc -> Printf.bprintf buf {|"FunCall",%a]|} fun_call fc
+    | SubScopeCall { name; inputs; body } ->
+      Printf.bprintf buf {|{"name":%a,"inputs":[%a],"body":[%a]}|} information
+        name (list var_def) inputs (list event) body
+
+  and var_def buf def =
+    Option.iter (Printf.bprintf buf {|{"pos":%a|} source_position) def.pos;
+    Printf.bprintf buf {|,"name":%a|} information def.name;
+    Printf.bprintf buf {|,"io":%a|} io_log def.io;
+    Printf.bprintf buf {|,"value":%a|} runtime_value def.value;
+    Option.iter
+      (Printf.bprintf buf {|,"fun_calls":[%a]}|} (list fun_call))
+      def.fun_calls
+
+  and fun_call buf fc =
+    Printf.bprintf buf {|{"fun_name":%a|} information fc.fun_name;
+    Printf.bprintf buf {|,"fun_inputs":[%a]|} (list var_def) fc.fun_inputs;
+    Printf.bprintf buf {|,"body":[%a]|} (list event) fc.body;
+    Printf.bprintf buf {|,"output":%a}|} var_def fc.output
+end
+
+module Json = struct
+  let str f x =
+    let buf = Buffer.create 800 in
+    f buf x;
+    Buffer.contents buf
+
+  open BufferedJson
+
+  let runtime_value = str runtime_value
+  let io_log = str io_log
+  let event = str event
+end
+
 let log_ref : raw_event list ref = ref []
 let reset_log () = log_ref := []
 let retrieve_log () = List.rev !log_ref
@ -313,8 +404,7 @@ let rec pp_events ?(is_first_call = true) ppf events =
    | Duration x -> Format.fprintf ppf "%s" (duration_to_string x)
    | Enum (_, (name, _)) -> Format.fprintf ppf "%s" name
    | Struct (name, attrs) ->
-      Format.fprintf ppf "@[<hv 2>%s = {@ %a@;<1 -2>}@]"
-        (String.concat "." name)
+      Format.fprintf ppf "@[<hv 2>%s = {@ %a@;<1 -2>}@]" name
        (Format.pp_print_list
           ~pp_sep:(fun ppf () -> Format.fprintf ppf ",@,")
           (fun fmt (name, value) ->
@ -414,7 +504,7 @@ module EventParser = struct
    | VariableDefinition (name, io, value) ->
      Printf.sprintf "VariableDefinition([ %s ], %s, %s)"
        (String.concat ", " name) (io_log_to_string io)
-        (yojson_of_runtime_value value |> Yojson.Safe.to_string)
+        (Json.runtime_value value)
    | DecisionTaken pos ->
      Printf.sprintf "DecisionTaken(%s:%d.%d-%d.%d)" pos.filename pos.start_line
        pos.start_column pos.end_line pos.end_column
--- a/runtimes/ocaml/runtime.mli
+++ b/runtimes/ocaml/runtime.mli
@ -57,13 +57,11 @@ type io_input =
  | Reentrant
      (** For variables defined in the scope that can also be redefined by the
          caller as they appear in the input. *)
-[@@deriving yojson_of]

 type io_log = {
  io_input : io_input;
  io_output : bool;  (** [true] if the variable is an output *)
 }
-[@@deriving yojson_of]

 (** {1 Exceptions} *)

@ -85,11 +83,10 @@ type runtime_value =
  | Decimal of decimal
  | Date of date
  | Duration of duration
-  | Enum of string list * (string * runtime_value)
-  | Struct of string list * (string * runtime_value) list
+  | Enum of string * (string * runtime_value)
+  | Struct of string * (string * runtime_value) list
  | Array of runtime_value Array.t
  | Unembeddable
-[@@deriving yojson_of]

 val unembeddable : 'a -> runtime_value
 val embed_unit : unit -> runtime_value
@ -115,7 +112,7 @@ val embed_array : ('a -> runtime_value) -> 'a Array.t -> runtime_value

 (** {2 Data structures} *)

-type information = string list [@@deriving yojson_of]
+type information = string list
 (** Represents information about a name in the code -- i.e. variable name,
    subscope name, etc...

@ -188,7 +185,6 @@ type event =
      inputs : var_def list;
      body : event list;
    }
-[@@deriving yojson_of]

 and var_def = {
  pos : source_position option;
@ -230,6 +226,16 @@ val log_decision_taken : source_position -> bool -> bool

 (** {3 Pretty printers} *)

+(** {4 Conversions to JSON} *)
+module Json : sig
+  (* val io_input: io_input -> string *)
+  val io_log : io_log -> string
+  val runtime_value : runtime_value -> string
+
+  (* val information: information -> string *)
+  val event : event -> string
+end
+
 val pp_events : ?is_first_call:bool -> Format.formatter -> event list -> unit
 (** [pp_events ~is_first_call ppf events] pretty prints in [ppf] the string
    representation of [events].