Fixes a part of issues

src/components/DistBuilder.re

@@ -117,13 +117,19 @@ module DemoDist = {
       <div>
         {switch (domain, unit, options) {
          | (Some(domain), Some(unit), Some(options)) =>
+           let distPlus =
              DistPlusIngredients.make(~guesstimatorString, ~domain, ~unit, ())
              |> DistPlusIngredients.toDistPlus(
                   ~sampleCount=options.sampleCount,
                   ~outputXYPoints=options.outputXYPoints,
                   ~truncateTo=options.truncateTo,
-              )
+                );
-           |> E.O.React.fmapOrNull(distPlus => <DistPlusPlot distPlus />)
+           switch (distPlus) {
+           | Some(distPlus) => <DistPlusPlot distPlus />
+           | _ =>
+             "Correct Guesstimator string input to show a distribution."
+             |> E.ste
+           };
          | _ =>
            "Nothing to show. Try to change the distribution description."
            |> E.ste

src/components/charts/DistributionPlot/distPlotD3.js

@@ -163,6 +163,7 @@ export class CdfChartD3 {
         this.addLollipopsChart(common);
       }
     } catch (e) {
+      this._container.selectAll("*").remove();
       throw e;
     }
     return this;

src/components/editor/main.js

@@ -135,6 +135,7 @@ function get_final_pdf(pdf_vals, bst_pts_and_idxs, output_grid) {
   var active_intervals = new Map();
   var active_endpoints = new bst.AVLTree();
   var final_pdf_vals = [];
+
   for (
     let out_grid_idx = 0;
     out_grid_idx < output_grid.length;
@@ -179,9 +180,19 @@ function get_final_pdf(pdf_vals, bst_pts_and_idxs, output_grid) {
       active_intervals.delete(interval_idx);
     }
   }
+
   return final_pdf_vals;
 }
 
+/**
+ * @param {string} str
+ * @param {string} char
+ * @returns {number}
+ */
+function get_count_of_chars(str, char) {
+  return str.split(char).length - 1;
+}
+
 /**
  * Entrypoint. Pass user input strings to this function,
  * get the corresponding pdf values and input points back.
@@ -195,11 +206,18 @@ function get_final_pdf(pdf_vals, bst_pts_and_idxs, output_grid) {
  */
 function get_pdf_from_user_input(user_input_string) {
   try {
+    const count_opened_bracket = get_count_of_chars(user_input_string, '(');
+    const count_closed_bracket = get_count_of_chars(user_input_string, ')');
+    if (count_opened_bracket !== count_closed_bracket) {
+      throw new Error('Count of brackets are not equal.');
+    }
+
     let parsed = parse.parse_initial_string(user_input_string);
     let mm_args = parse.separate_mm_args(parsed.mm_args_string);
-
     const is_mm = mm_args.distrs.length > 0;
-    if (!parsed.outer_string) return [[], [], true];
+    if (!parsed.outer_string) {
+      throw new Error('Parse string is empty.');
+    }
 
     let tree = new bst.AVLTree();
     let possible_start_pts = [];
@@ -232,6 +250,7 @@ function get_pdf_from_user_input(user_input_string) {
 
     let output_grid = evenly_spaced_grid(start_pt, end_pt, OUTPUT_GRID_NUMEL);
     let final_pdf_vals = get_final_pdf(all_vals, tree, output_grid);
+
     return [final_pdf_vals, output_grid, false];
   } catch (e) {
     return [[], [], true];

src/components/editor/parse.js

@@ -3,6 +3,7 @@ const math = _math.create(_math.all);
 
 // Functions for parsing/processing user input strings are here
 
+// @todo: Do not use objects.
 const DISTR_REGEXS = [
   /beta\(/g,
   /(log)?normal\(/g,
@@ -12,7 +13,6 @@ const DISTR_REGEXS = [
 ];
 
 /**
- *
  * @param user_input_string
  * @returns {{mm_args_string: string, outer_string: string}}
  */
@@ -20,6 +20,7 @@ function parse_initial_string(user_input_string) {
   let outer_output_string = "";
   let mm_args_string = "";
   let idx = 0;
+
   while (idx < user_input_string.length) {
     if (
       user_input_string.substring(idx - 11, idx) === "multimodal(" ||
@@ -42,6 +43,7 @@ function parse_initial_string(user_input_string) {
       idx += 1;
     }
   }
+
   return {
     outer_string: outer_output_string,
     mm_args_string: mm_args_string