Add plot to documentation

packages/components/src/components/DistributionChart.tsx

@@ -3,8 +3,9 @@ import {
   SqDistribution,
   result,
   SqDistributionError,
+  LabeledDistribution,
   resultMap,
-  SqRecord,
+  SqPlot,
   environment,
   SqDistributionTag,
 } from "@quri/squiggle-lang";
@@ -17,7 +18,6 @@ import {
   DistributionChartSpecOptions,
 } from "../lib/distributionSpecBuilder";
 import { NumberShower } from "./NumberShower";
-import { Plot, parsePlot } from "../lib/plotParser";
 import { flattenResult } from "../lib/utility";
 import { hasMassBelowZero } from "../lib/distributionUtils";
 
@@ -28,27 +28,15 @@ export type DistributionPlottingSettings = {
 } & DistributionChartSpecOptions;
 
 export type DistributionChartProps = {
-  plot: Plot;
   environment: environment;
   width?: number;
   height: number;
   xAxisType?: "number" | "dateTime";
-} & DistributionPlottingSettings;
-
-export function defaultPlot(distribution: SqDistribution): Plot {
-  return { distributions: [{ name: "default", distribution }] };
-}
-
-export function makePlot(record: SqRecord): Plot | void {
-  const plotResult = parsePlot(record);
-  if (plotResult.tag === "Ok") {
-    return plotResult.value;
-  }
-}
+} & DistributionPlottingSettings &
+  ({ plot: SqPlot } | { distribution: SqDistribution });
 
 export const DistributionChart: React.FC<DistributionChartProps> = (props) => {
   const {
-    plot,
     environment,
     height,
     showSummary,
@@ -57,8 +45,14 @@ export const DistributionChart: React.FC<DistributionChartProps> = (props) => {
     actions = false,
   } = props;
   const [sized] = useSize((size) => {
-    const shapes = flattenResult(
-      plot.distributions.map((x) =>
+    let distributions: LabeledDistribution[];
+    if ("plot" in props) {
+      distributions = props.plot.getDistributions();
+    } else {
+      distributions = [{ name: "default", distribution: props.distribution }];
+    }
+    let shapes = flattenResult(
+      distributions.map((x) =>
         resultMap(x.distribution.pointSet(environment), (pointSet) => ({
           name: x.name,
           // color: x.color, // not supported yet
@@ -77,7 +71,7 @@ export const DistributionChart: React.FC<DistributionChartProps> = (props) => {
 
     // if this is a sample set, include the samples
     const samples: number[] = [];
-    for (const { distribution } of plot?.distributions) {
+    for (const { distribution } of distributions) {
       if (distribution.tag === SqDistributionTag.SampleSet) {
         samples.push(...distribution.value());
       }
@@ -126,9 +120,9 @@ export const DistributionChart: React.FC<DistributionChartProps> = (props) => {
           />
         )}
         <div className="flex justify-center">
-          {showSummary && plot.distributions.length === 1 && (
+          {showSummary && distributions.length === 1 && (
             <SummaryTable
-              distribution={plot.distributions[0].distribution}
+              distribution={distributions[0].distribution}
               environment={environment}
             />
           )}

packages/components/src/components/FunctionChart1Dist.tsx

@@ -15,7 +15,6 @@ import * as percentilesSpec from "../vega-specs/spec-percentiles.json";
 import {
   DistributionChart,
   DistributionPlottingSettings,
-  defaultPlot,
 } from "./DistributionChart";
 import { NumberShower } from "./NumberShower";
 import { ErrorAlert } from "./Alert";
@@ -184,7 +183,7 @@ export const FunctionChart1Dist: React.FC<FunctionChart1DistProps> = ({
     mouseItem.tag === "Ok" &&
     mouseItem.value.tag === SqValueTag.Distribution ? (
       <DistributionChart
-        plot={defaultPlot(mouseItem.value.value)}
+        distribution={mouseItem.value.value}
         environment={environment}
         width={400}
         height={50}
@@ -194,7 +193,7 @@ export const FunctionChart1Dist: React.FC<FunctionChart1DistProps> = ({
 
   let getPercentilesMemoized = React.useMemo(
     () => getPercentiles({ chartSettings, fn, environment }),
-    [environment, fn]
+    [chartSettings, environment, fn]
   );
 
   return (

packages/components/src/components/SquiggleViewer/ExpressionViewer.tsx

@@ -1,7 +1,7 @@
 import React, { useContext } from "react";
 import { SqDistributionTag, SqValue, SqValueTag } from "@quri/squiggle-lang";
 import { NumberShower } from "../NumberShower";
-import { DistributionChart, defaultPlot, makePlot } from "../DistributionChart";
+import { DistributionChart } from "../DistributionChart";
 import { FunctionChart } from "../FunctionChart";
 import clsx from "clsx";
 import { VariableBox } from "./VariableBox";
@@ -104,7 +104,7 @@ export const ExpressionViewer: React.FC<Props> = ({ value, width }) => {
           {(settings) => {
             return (
               <DistributionChart
-                plot={defaultPlot(value.value)}
+                distribution={value.value}
                 environment={settings.environment}
                 {...settings.distributionPlotSettings}
                 height={settings.height}
@@ -219,63 +219,61 @@ export const ExpressionViewer: React.FC<Props> = ({ value, width }) => {
         </VariableBox>
       );
     }
+    case SqValueTag.Plot:
+      const plot = value.value;
+      return (
+        <VariableBox
+          value={value}
+          heading="Plot"
+          renderSettingsMenu={({ onChange }) => {
+            let disableLogX = plot.getDistributions().some((x) => {
+              let pointSet = x.distribution.pointSet(
+                getMergedSettings(value.location).environment
+              );
+              return (
+                pointSet.tag === "Ok" &&
+                hasMassBelowZero(pointSet.value.asShape())
+              );
+            });
+            return (
+              <ItemSettingsMenu
+                value={value}
+                onChange={onChange}
+                disableLogX={disableLogX}
+                withFunctionSettings={false}
+              />
+            );
+          }}
+        >
+          {(settings) => {
+            return (
+              <DistributionChart
+                plot={plot}
+                environment={settings.environment}
+                {...settings.distributionPlotSettings}
+                height={settings.height}
+                width={width}
+              />
+            );
+          }}
+        </VariableBox>
+      );
     case SqValueTag.Record:
-      const plot = makePlot(value.value);
-      if (plot) {
-        return (
-          <VariableBox
-            value={value}
-            heading="Plot"
-            renderSettingsMenu={({ onChange }) => {
-              let disableLogX = plot.distributions.some((x) => {
-                let pointSet = x.distribution.pointSet(
-                  getMergedSettings(value.location).environment
-                );
-                return (
-                  pointSet.tag === "Ok" &&
-                  hasMassBelowZero(pointSet.value.asShape())
-                );
-              });
-              return (
-                <ItemSettingsMenu
-                  value={value}
-                  onChange={onChange}
-                  disableLogX={disableLogX}
-                  withFunctionSettings={false}
+      return (
+        <VariableList value={value} heading="Record">
+          {(_) =>
+            value.value
+              .entries()
+              .map(([key, r]) => (
+                <ExpressionViewer
+                  key={key}
+                  value={r}
+                  width={width !== undefined ? width - 20 : width}
                 />
-              );
-            }}
-          >
-            {(settings) => {
-              return (
-                <DistributionChart
-                  plot={plot}
-                  environment={settings.environment}
-                  {...settings.distributionPlotSettings}
-                  height={settings.height}
-                  width={width}
-                />
-              );
-            }}
-          </VariableBox>
-        );
-      } else {
-        return (
-          <VariableList value={value} heading="Record">
-            {(_) =>
-              value.value
-                .entries()
-                .map(([key, r]) => (
-                  <ExpressionViewer
-                    key={key}
-                    value={r}
-                    width={width !== undefined ? width - 20 : width}
-                  />
-                ))
-            }
-          </VariableList>
-        );
-      }
+              ))
+          }
+        </VariableList>
+      );
     case SqValueTag.Array:
       return (
         <VariableList value={value} heading="Array">

packages/components/src/lib/plotParser.ts

@@ -1,83 +0,0 @@
-import * as yup from "yup";
-import {
-  SqValue,
-  SqValueTag,
-  SqDistribution,
-  result,
-  SqRecord,
-} from "@quri/squiggle-lang";
-
-export type LabeledDistribution = {
-  name: string;
-  distribution: SqDistribution;
-  color?: string;
-};
-
-export type Plot = {
-  distributions: LabeledDistribution[];
-};
-
-function error<a, b>(err: b): result<a, b> {
-  return { tag: "Error", value: err };
-}
-
-function ok<a, b>(x: a): result<a, b> {
-  return { tag: "Ok", value: x };
-}
-
-const schema = yup
-  .object()
-  .noUnknown()
-  .strict()
-  .shape({
-    distributions: yup
-      .array()
-      .required()
-      .of(
-        yup.object().required().shape({
-          name: yup.string().required(),
-          distribution: yup.mixed().required(),
-        })
-      ),
-  });
-
-type JsonObject =
-  | string
-  | { [key: string]: JsonObject }
-  | JsonObject[]
-  | SqDistribution;
-
-function toJson(val: SqValue): JsonObject {
-  if (val.tag === SqValueTag.String) {
-    return val.value;
-  } else if (val.tag === SqValueTag.Record) {
-    return toJsonRecord(val.value);
-  } else if (val.tag === SqValueTag.Array) {
-    return val.value.getValues().map(toJson);
-  } else if (val.tag === SqValueTag.Distribution) {
-    return val.value;
-  } else {
-    throw new Error("Could not parse object of type " + val.tag);
-  }
-}
-
-function toJsonRecord(val: SqRecord): JsonObject {
-  let recordObject: JsonObject = {};
-  val.entries().forEach(([key, value]) => (recordObject[key] = toJson(value)));
-  return recordObject;
-}
-
-export function parsePlot(record: SqRecord): result<Plot, string> {
-  try {
-    const plotRecord = schema.validateSync(toJsonRecord(record));
-    if (plotRecord.distributions) {
-      return ok({ distributions: plotRecord.distributions.map((x) => x) });
-    } else {
-      // I have no idea why yup's typings thinks this is possible
-      return error("no distributions field. Should never get here");
-    }
-  } catch (e) {
-    const message = e instanceof Error ? e.message : "Unknown error";
-    return error(message);
-  }
-}

packages/squiggle-lang/__tests__/Reducer/Reducer_test.res

@@ -99,7 +99,7 @@ describe("stacktraces", () => {
 
     expect(
       error,
-    )->toBe(`Error: There are function matches for add(), but with different arguments: [add(number, number)]; [add(distribution, number)]; [add(number, distribution)]; [add(distribution, distribution)]; [add(date, duration)]; [add(duration, duration)]
+    )->toBe(`Error: There are function matches for add(), but with different arguments: [add(number, number)]; [add(date, duration)]; [add(duration, duration)]; [add(distribution, number)]; [add(number, distribution)]; [add(distribution, distribution)]
 Stack trace:
   f at line 4, column 5
   g at line 6, column 12

packages/squiggle-lang/__tests__/SquiggleLibrary/SquiggleLibrary_Plot_test.res

@@ -0,0 +1,20 @@
+open Jest
+open Reducer_TestHelpers
+
+describe("Plot Library", () => {
+  testEvalToBe(
+    `Plot.dist({
+    show: [{
+      name: "normal",
+      value: normal(0, 1)
+    }, {
+      name: "lognormal", 
+      value: 1 to 2
+    }, {
+      name: "constant", 
+      value: 3
+    }]
+})`,
+    "Ok(Plot showing normal,lognormal,constant)",
+  )
+})

packages/squiggle-lang/src/js/SqPlot.ts

@@ -0,0 +1,25 @@
+import * as RSPlot from "../rescript/ForTS/ForTS_SquiggleValue/ForTS_SquiggleValue_Plot.gen";
+import { SqDistribution, wrapDistribution } from "./SqDistribution";
+import { SqValueLocation } from "./SqValueLocation";
+
+type T = RSPlot.squiggleValue_Plot;
+
+export type LabeledDistribution = {
+  name: string;
+  distribution: SqDistribution;
+};
+
+export class SqPlot {
+  constructor(private _value: T, public location: SqValueLocation) {}
+
+  getDistributions(): LabeledDistribution[] {
+    return this._value.distributions.map((v: RSPlot.labeledDistribution) => ({
+      ...v,
+      distribution: wrapDistribution(v.distribution),
+    }));
+  }
+
+  toString() {
+    return RSPlot.toString(this._value);
+  }
+}

packages/squiggle-lang/src/js/SqValue.ts

@@ -4,6 +4,7 @@ import { wrapDistribution } from "./SqDistribution";
 import { SqLambda } from "./SqLambda";
 import { SqLambdaDeclaration } from "./SqLambdaDeclaration";
 import { SqRecord } from "./SqRecord";
+import { SqPlot } from "./SqPlot";
 import { SqArray } from "./SqArray";
 import { SqValueLocation } from "./SqValueLocation";
 
@@ -91,6 +92,14 @@ export class SqNumberValue extends SqAbstractValue {
   }
 }
 
+export class SqPlotValue extends SqAbstractValue {
+  tag = Tag.Plot as const;
+
+  get value() {
+    return new SqPlot(this.valueMethod(RSValue.getPlot), this.location);
+  }
+}
+
 export class SqRecordValue extends SqAbstractValue {
   tag = Tag.Record as const;
 
@@ -131,6 +140,7 @@ const tagToClass = {
   [Tag.Distribution]: SqDistributionValue,
   [Tag.Lambda]: SqLambdaValue,
   [Tag.Number]: SqNumberValue,
+  [Tag.Plot]: SqPlotValue,
   [Tag.Record]: SqRecordValue,
   [Tag.String]: SqStringValue,
   [Tag.TimeDuration]: SqTimeDurationValue,
@@ -148,6 +158,7 @@ export type SqValue =
   | SqLambdaValue
   | SqNumberValue
   | SqRecordValue
+  | SqPlotValue
   | SqStringValue
   | SqTimeDurationValue
   | SqVoidValue;

packages/squiggle-lang/src/js/index.ts

@@ -6,6 +6,7 @@ export { result } from "../rescript/ForTS/ForTS_Result_tag";
 export { SqDistribution, SqDistributionTag } from "./SqDistribution";
 export { SqDistributionError } from "./SqDistributionError";
 export { SqRecord } from "./SqRecord";
+export { SqPlot, LabeledDistribution } from "./SqPlot";
 export { SqLambda } from "./SqLambda";
 export { SqProject };
 export { SqValue, SqValueTag };
@@ -14,7 +15,7 @@ export {
   defaultEnvironment,
 } from "../rescript/ForTS/ForTS_Distribution/ForTS_Distribution.gen";
 export { SqError, SqFrame, SqLocation } from "./SqError";
-export { SqShape } from "./SqPointSetDist";
+export { SqShape, SqPoint } from "./SqPointSetDist";
 
 export { resultMap } from "./types";
 

packages/squiggle-lang/src/rescript/FR/FR_Plot.res

@@ -0,0 +1,146 @@
+open FunctionRegistry_Core
+open FunctionRegistry_Helpers
+
+let nameSpace = "Plot"
+
+module FnApp = {
+  type fnApp<'a> = {
+    result: Reducer_T.value => result<'a, SqError.Message.t>,
+    typeRequired: frType,
+  }
+
+  let fmap = (f: 'a => 'b, m: fnApp<'a>): fnApp<'b> => {
+    {
+      result: (a: Reducer_T.value) => E.R.fmap(f, m.result(a)),
+      typeRequired: m.typeRequired,
+    }
+  }
+
+  module Record = {
+    type t<'a> = {
+      result: Reducer_T.map => result<'a, SqError.Message.t>,
+      typesRequired: array<(string, frType)>,
+    }
+
+    let getField = (key: string, parser: fnApp<'a>): t<'a> => {
+      let func = (a: Reducer_T.map) =>
+        switch Belt.Map.String.get(a, key) {
+        | Some(x) => parser.result(x)
+        | None => Error(impossibleError)
+        }
+      {result: func, typesRequired: [(key, parser.typeRequired)]}
+    }
+
+    let merge = (m1: t<'a>, m2: t<'b>): t<('a, 'b)> => {
+      {
+        result: (a: Reducer_T.map) => E.R.merge(m1.result(a), m2.result(a)),
+        typesRequired: Belt.Array.concat(m1.typesRequired, m2.typesRequired),
+      }
+    }
+
+    let fmap = (f: 'a => 'b, m: t<'a>): t<'b> => {
+      {
+        result: (a: Reducer_T.map) => E.R.fmap(f, m.result(a)),
+        typesRequired: m.typesRequired,
+      }
+    }
+
+    let app = (m1: t<'a => 'b>, m2: t<'a>): t<'b> => {
+      {
+        result: (a: Reducer_T.map) =>
+          E.R.merge(m1.result(a), m2.result(a))->E.R2.fmap(((f, x)) => f(x)),
+        typesRequired: Belt.Array.concat(m1.typesRequired, m2.typesRequired),
+      }
+    }
+  }
+
+  let getString: fnApp<string> = {
+    let func = (a: Reducer_T.value) =>
+      switch a {
+      | IEvString(s) => Ok(s)
+      | _ => Error(impossibleError)
+      }
+    {result: func, typeRequired: FRTypeString}
+  }
+
+  let getArray = (child: fnApp<'a>): fnApp<array<'a>> => {
+    let func = (a: Reducer_T.value) =>
+      switch a {
+      | IEvArray(x) => x->E.A2.fmap(child.result)->E.A.R.firstErrorOrOpen
+      | _ => Error(impossibleError)
+      }
+    {result: func, typeRequired: FRTypeArray(child.typeRequired)}
+  }
+  let getRecord = (recMonad: Record.t<'a>): fnApp<'a> => {
+    let func = (a: Reducer_T.value) =>
+      switch a {
+      | IEvRecord(s) => recMonad.result(s)
+      | _ => Error(impossibleError)
+      }
+    {result: func, typeRequired: FRTypeRecord(recMonad.typesRequired)}
+  }
+
+  let getDistOrNumber: fnApp<GenericDist.t> = {
+    let func = (a: Reducer_T.value) =>
+      switch a {
+      | IEvDistribution(s) => Ok(s)
+      | IEvNumber(s) => Ok(GenericDist.fromFloat(s))
+      | _ => Error(impossibleError)
+      }
+    {result: func, typeRequired: FRTypeDistOrNumber}
+  }
+
+  let oneArgDef = (
+    name: string,
+    arg1: fnApp<'a>,
+    def: 'a => result<Reducer_T.value, SqError.Message.t>,
+  ): FnDefinition.t =>
+    FnDefinition.make(
+      ~name,
+      ~inputs=[arg1.typeRequired],
+      ~run=(inputs, _, _) => {
+        E.R.bind(arg1.result(inputs[0]), def)
+      },
+      (),
+    )
+}
+
+module Internals = {
+  let makeLabeledDistribution = (
+    name: string,
+    distribution: GenericDist.t,
+  ): Reducer_T.labeledDistribution => {name: name, distribution: distribution}
+
+  let getLabeledDistribution: FnApp.fnApp<Reducer_T.labeledDistribution> = {
+    makeLabeledDistribution
+    ->FnApp.Record.fmap(FnApp.Record.getField("name", FnApp.getString))
+    ->FnApp.Record.app(FnApp.Record.getField("value", FnApp.getDistOrNumber))
+    ->FnApp.getRecord
+  }
+
+  let makePlot = (show: array<Reducer_T.labeledDistribution>): Reducer_T.plotValue => {
+    distributions: show,
+  }
+
+  let parsePlotValue: FnApp.fnApp<Reducer_T.plotValue> = {
+    makePlot
+    ->FnApp.Record.fmap(FnApp.Record.getField("show", FnApp.getArray(getLabeledDistribution)))
+    ->FnApp.getRecord
+  }
+}
+
+let library = [
+  Function.make(
+    ~name="dist",
+    ~nameSpace,
+    ~requiresNamespace=true,
+    ~output=EvtPlot,
+    ~examples=[
+      `Plot.dist({show: [{name: "Control", value: 1 to 2}, {name: "Treatment", value: 1.5 to 2.5}]}) `,
+    ],
+    ~definitions=[
+      FnApp.oneArgDef("dist", Internals.parsePlotValue, (a: Reducer_T.plotValue) => Ok(IEvPlot(a))),
+    ],
+    (),
+  ),
+]

packages/squiggle-lang/src/rescript/ForTS/ForTS_SquiggleValue/ForTS_SquiggleValue.res

@@ -6,6 +6,7 @@ type error = SqError.t //use
 type squiggleValue_Declaration = ForTS_SquiggleValue_Declaration.squiggleValue_Declaration //use
 type squiggleValue_Distribution = ForTS_SquiggleValue_Distribution.squiggleValue_Distribution //use
 type squiggleValue_Lambda = ForTS_SquiggleValue_Lambda.squiggleValue_Lambda //use
+@genType type squiggleValue_Plot = Reducer_T.plotValue //use
 
 // Return values are kept as they are if they are JavaScript types.
 
@@ -30,6 +31,9 @@ external svtLambda_: string = "Lambda"
 @module("./ForTS_SquiggleValue_tag") @scope("squiggleValueTag")
 external svtNumber_: string = "Number"
 
+@module("./ForTS_SquiggleValue_tag") @scope("squiggleValueTag")
+external svtPlot_: string = "Plot"
+
 @module("./ForTS_SquiggleValue_tag") @scope("squiggleValueTag")
 external svtRecord_: string = "Record"
 
@@ -57,6 +61,7 @@ let getTag = (variant: squiggleValue): squiggleValueTag =>
   | IEvDistribution(_) => svtDistribution_->castEnum
   | IEvLambda(_) => svtLambda_->castEnum
   | IEvNumber(_) => svtNumber_->castEnum
+  | IEvPlot(_) => svtPlot_->castEnum
   | IEvRecord(_) => svtRecord_->castEnum
   | IEvString(_) => svtString_->castEnum
   | IEvTimeDuration(_) => svtTimeDuration_->castEnum
@@ -122,6 +127,13 @@ let getNumber = (variant: squiggleValue): option<float> =>
   | _ => None
   }
 
+@genType
+let getPlot = (variant: squiggleValue): option<squiggleValue_Plot> =>
+  switch variant {
+  | IEvPlot(value) => value->Some
+  | _ => None
+  }
+
 @genType
 let getRecord = (variant: squiggleValue): option<squiggleValue_Record> =>
   switch variant {

packages/squiggle-lang/src/rescript/ForTS/ForTS_SquiggleValue/ForTS_SquiggleValue_Plot.res

@@ -0,0 +1,6 @@
+type squiggleValue = ForTS_SquiggleValue.squiggleValue //use
+@genType type squiggleValue_Plot = ForTS_SquiggleValue.squiggleValue_Plot //re-export recursive type
+@genType type labeledDistribution = Reducer_T.labeledDistribution // use
+
+@genType
+let toString = (v: squiggleValue_Plot) => Reducer_Value.toStringPlot(v)

packages/squiggle-lang/src/rescript/ForTS/ForTS_SquiggleValue/ForTS_SquiggleValue_tag.ts

@@ -6,6 +6,7 @@ export enum squiggleValueTag {
   Distribution = "Distribution",
   Lambda = "Lambda",
   Number = "Number",
+  Plot = "Plot",
   Record = "Record",
   String = "String",
   TimeDuration = "TimeDuration",

packages/squiggle-lang/src/rescript/FunctionRegistry/FunctionRegistry_Core.res

@@ -1,4 +1,5 @@
 type internalExpressionValueType = Reducer_Value.internalExpressionValueType
+let valueTypeToString = Reducer_Value.valueTypeToString
 type errorMessage = SqError.Message.t
 
 /*

packages/squiggle-lang/src/rescript/FunctionRegistry/FunctionRegistry_Library.res

@@ -1,18 +1,19 @@
 let fnList = Belt.Array.concatMany([
   FR_Builtin.library,
+  FR_Danger.library,
+  FR_Date.library,
   FR_Dict.library,
   FR_Dist.library,
-  FR_Danger.library,
   FR_Fn.library,
-  FR_Sampleset.library,
-  FR_List.library,
-  FR_Number.library,
-  FR_Pointset.library,
-  FR_Scoring.library,
   FR_GenericDist.library,
-  FR_Units.library,
-  FR_Date.library,
+  FR_List.library,
   FR_Math.library,
+  FR_Number.library,
+  FR_Plot.library,
+  FR_Pointset.library,
+  FR_Sampleset.library,
+  FR_Scoring.library,
+  FR_Units.library,
 ])
 
 let registry = FunctionRegistry_Core.Registry.make(fnList)

packages/squiggle-lang/src/rescript/Reducer/Reducer_T.res

@@ -9,10 +9,12 @@ type rec value =
   | IEvDistribution(DistributionTypes.genericDist)
   | IEvLambda(lambdaValue)
   | IEvNumber(float)
+  | IEvPlot(plotValue)
   | IEvRecord(map)
   | IEvString(string)
   | IEvTimeDuration(float)
   | IEvVoid
+
 @genType.opaque and arrayValue = array<value>
 @genType.opaque and map = Belt.Map.String.t<value>
 and lambdaBody = (array<value>, context, reducerFn) => value
@@ -66,4 +68,12 @@ and context = {
 
 and reducerFn = (expression, context) => (value, context)
 
+@genType and plotValue = {distributions: array<labeledDistribution>}
+
+@genType
+and labeledDistribution = {
+  name: string,
+  distribution: DistributionTypes.genericDist,
+}
+
 let topFrameName = "<top>"

packages/squiggle-lang/src/rescript/Reducer/Reducer_Value.res

@@ -14,6 +14,7 @@ let rec toString = (aValue: T.value) =>
   | IEvDistribution(dist) => toStringDistribution(dist)
   | IEvLambda(lambdaValue) => toStringLambda(lambdaValue)
   | IEvNumber(aNumber) => toStringNumber(aNumber)
+  | IEvPlot(aPlot) => toStringPlot(aPlot)
   | IEvRecord(aMap) => aMap->toStringRecord
   | IEvString(aString) => toStringString(aString)
   | IEvTimeDuration(t) => toStringTimeDuration(t)
@@ -35,6 +36,10 @@ and toStringLambda = (lambdaValue: T.lambdaValue) => {
   }
 }
 and toStringNumber = aNumber => Js.String.make(aNumber)
+and toStringPlot = aPlot => {
+  let chartNames = E.A.fmap((x: Reducer_T.labeledDistribution) => x.name, aPlot.distributions)
+  `Plot showing ${Js.Array2.toString(chartNames)}`
+}
 and toStringRecord = aMap => aMap->toStringMap
 and toStringString = aString => `'${aString}'`
 and toStringSymbol = aString => `:${aString}`
@@ -59,6 +64,7 @@ let toStringWithType = (aValue: T.value) =>
   | IEvDistribution(_) => `Distribution::${toString(aValue)}`
   | IEvLambda(_) => `Lambda::${toString(aValue)}`
   | IEvNumber(_) => `Number::${toString(aValue)}`
+  | IEvPlot(_) => `Plot::${toString(aValue)}`
   | IEvRecord(_) => `Record::${toString(aValue)}`
   | IEvString(_) => `String::${toString(aValue)}`
   | IEvTimeDuration(_) => `Date::${toString(aValue)}`
@@ -91,6 +97,7 @@ type internalExpressionValueType =
   | EvtDistribution
   | EvtLambda
   | EvtNumber
+  | EvtPlot
   | EvtRecord
   | EvtString
   | EvtTimeDuration
@@ -109,6 +116,7 @@ let valueToValueType = (value: T.value) =>
   | IEvDistribution(_) => EvtDistribution
   | IEvLambda(_) => EvtLambda
   | IEvNumber(_) => EvtNumber
+  | IEvPlot(_) => EvtPlot
   | IEvRecord(_) => EvtRecord
   | IEvString(_) => EvtString
   | IEvTimeDuration(_) => EvtTimeDuration
@@ -129,6 +137,7 @@ let valueTypeToString = (valueType: internalExpressionValueType): string =>
   | EvtDistribution => `Distribution`
   | EvtLambda => `Lambda`
   | EvtNumber => `Number`
+  | EvtPlot => `Plot`
   | EvtRecord => `Record`
   | EvtString => `String`
   | EvtTimeDuration => `Duration`

packages/website/docs/Api/Plot.md

@@ -0,0 +1,19 @@
+---
+sidebar_position: 8
+title: Plot
+---
+
+Plot objects can be created to make plots of different kinds. If you wish to plot
+multiple distributions simultaneously, you can use `Plot.dist`.
+
+**Example**
+
+### dist
+
+```
+Plot.dist({show: list({name: string, value: distribution|number})})
+```
+
+```js
+Plot.dist({show: [{name: "normal", value: normal(0, 1)}, {name: "lognormal", value: 2 to 3}]})
+```