Do not print stdout and stderr in stanc.js

src/stancjs/stancjs.ml

@@ -45,21 +45,20 @@ let stan2cpp model_name model_string flags =
           "Semantic check failed but reported no errors. This should never \
            happen."
   in
-  if is_flag_set "version" then Result.Ok (Fmt.strf "%s" version, [])
+  if is_flag_set "version" then Result.Ok (Fmt.strf "%s" version)
   else
     Result.bind ast
       ~f:
         (Fn.compose semantic_err_to_string
            Semantic_check.semantic_check_program)
     |> Result.map ~f:(fun typed_ast ->
            if is_flag_set "print-canonical" then
-             ( Pretty_printing.pretty_print_typed_program
-                 (Canonicalize.canonicalize_program typed_ast)
-             , [] )
+             Pretty_printing.pretty_print_typed_program
+               (Canonicalize.canonicalize_program typed_ast)
            else if is_flag_set "auto-format" then
              match ast with
-             | Result.Ok f -> (Pretty_printing.pretty_print_program f, [])
-             | _ -> ("Error: This should not happend!", [])
+             | Result.Ok f -> Pretty_printing.pretty_print_program f
+             | _ -> "Error: This should not happend!"
            else
              let mir = Ast_to_Mir.trans_prog model_name typed_ast in
              let tx_mir = Transform_Mir.trans_prog mir in
@@ -72,21 +71,26 @@ let stan2cpp model_name model_string flags =
                Pedantic_analysis.print_warn_uninitialized mir ;
              if is_flag_set "warn-pedantic" then
                Pedantic_analysis.print_warn_pedantic mir ;
-             (cpp, []) )
+             cpp )
+
+let stanc_stdout = ref ""
+let stanc_stderr = ref ""
 
 let wrap_result = function
-  | Result.Ok (s, k) ->
+  | Result.Ok s ->
       Js.Unsafe.obj
         [| ("result", Js.Unsafe.inject (Js.string s))
-         ; ( "warnings"
-           , Js.Unsafe.inject
-               (Js.array (List.to_array (List.map ~f:Js.string k))) ) |]
+         ; ("warnings", Js.Unsafe.inject (Js.string !stanc_stderr)) |]
   | Error e ->
       Js.Unsafe.obj
         [| ("errors", Js.Unsafe.inject (Array.map ~f:Js.string [|e|]))
-         ; ("warnings", Js.Unsafe.inject Js.array_empty) |]
+         ; ("warnings", Js.Unsafe.inject (Js.string !stanc_stderr)) |]
 
 let stan2cpp_wrapped name code (flags : Js.string_array Js.t Js.opt) =
+  stanc_stdout := "" ;
+  stanc_stderr := "" ;
+  Sys_js.set_channel_flusher stdout (fun s -> stanc_stdout := !stanc_stdout ^ s) ;
+  Sys_js.set_channel_flusher stderr (fun s -> stanc_stderr := !stanc_stderr ^ s) ;
   stan2cpp (Js.to_string name) (Js.to_string code)
     Js.(
       Opt.map flags (fun a ->

test/stancjs/pedantic.js

@@ -11,15 +11,26 @@ model {
 }
 `
 var pedantic_test = stanc.stanc("pedantic", pedantic_model, ["warn-pedantic"]);
+if (pedantic_test.warnings) {
+    console.log(pedantic_test.warnings)
+}
 
 var pedantic_test = stanc.stanc("pedantic", pedantic_model);
-
+if (pedantic_test.warnings) {
+    console.log(pedantic_test.warnings)
+}
 var warn_uninit_model = `
 transformed data { 
     real tt;
     tt = tt + 2;
 }
 `
 var warn_uninit_test = stanc.stanc("uninit", warn_uninit_model, ["warn-uninitialized"]);
+if (warn_uninit_test.warnings) {
+    console.log(warn_uninit_test.warnings)
+}
 
 var warn_uninit_test = stanc.stanc("uninit", warn_uninit_model);
+if (warn_uninit_test.warnings) {
+    console.log(warn_uninit_test.warnings)
+}

test/stancjs/stancjs.expected

@@ -44,11 +44,20 @@ Warning:
 Warning at 'string', line 7, column 17 to column 22:
   Argument 10000 suggests there may be parameters that are not unit scale;
   consider rescaling with a multiplier (see manual section 22.12).
+
 Warning at 'string', line 4, column 9 to column 11:
   The variable tt may not have been assigned a value before its use.
+
 $ node standalone-functions.js
 
 $ node version.js
 %%NAME%% %%VERSION%%
 %%NAME%% %%VERSION%%
 %%NAME%% %%VERSION%%
+$ node warnings.js
+
+Warning: deprecated language construct used in 'string', line 4, column 4:
+
+Comments beginning with # are deprecated. Please use // in place of # for line comments.
+
+

test/stancjs/warnings.js

@@ -0,0 +1,14 @@
+var stanc = require('../../src/stancjs/stancjs.bc.js');
+var utils = require("./utils/utils.js");
+
+var deprecated_model = `
+parameters {
+    real y;
+    # hash comment is deprecated
+}
+model {
+    y ~ normal(0,1);
+}
+`
+var deprecated_test = stanc.stanc("deprecated", deprecated_model);
+console.log(deprecated_test.warnings)