opt-out of boolean range; custom scheme

Author: mbostock

src/scales.js

@@ -4,7 +4,7 @@ import {registry, color, position, radius, opacity, symbol, length} from "./scal
 import {ScaleLinear, ScaleSqrt, ScalePow, ScaleLog, ScaleSymlog, ScaleQuantile, ScaleThreshold, ScaleIdentity} from "./scales/quantitative.js";
 import {ScaleDiverging, ScaleDivergingSqrt, ScaleDivergingPow, ScaleDivergingLog, ScaleDivergingSymlog} from "./scales/diverging.js";
 import {ScaleTime, ScaleUtc} from "./scales/temporal.js";
-import {ScaleOrdinal, ScalePoint, ScaleBand} from "./scales/ordinal.js";
+import {ScaleOrdinal, ScalePoint, ScaleBand, ordinalImplicit} from "./scales/ordinal.js";
 
 export function Scales(channels, {
   inset: globalInset = 0,
@@ -172,7 +172,7 @@ function Scale(key, channels = [], options = {}) {
     case "diverging-pow": return ScaleDivergingPow(key, channels, options);
     case "diverging-log": return ScaleDivergingLog(key, channels, options);
     case "diverging-symlog": return ScaleDivergingSymlog(key, channels, options);
-    case "categorical": case "ordinal": return ScaleOrdinal(key, channels, options);
+    case "categorical": case "ordinal": case ordinalImplicit: return ScaleOrdinal(key, channels, options);
     case "cyclical": case "sequential": case "linear": return ScaleLinear(key, channels, options);
     case "sqrt": return ScaleSqrt(key, channels, options);
     case "threshold": return ScaleThreshold(key, channels, options);
@@ -255,7 +255,7 @@ function inferScaleType(key, channels, {type, domain, range, scheme}) {
 function asOrdinalType(kind) {
   switch (kind) {
     case position: return "point";
-    case color: return "categorical";
+    case color: return ordinalImplicit;
     default: return "ordinal";
   }
 }

src/scales/ordinal.js

@@ -6,14 +6,20 @@ import {none} from "../style.js";
 import {registry, color, symbol} from "./index.js";
 import {maybeBooleanRange, ordinalScheme, quantitativeScheme} from "./schemes.js";
 
+// This denotes an implicitly ordinal color scale: the scale type was not set,
+// but the associated values are strings or booleans. If the associated defined
+// values are entirely boolean, the range will default to greys. You can opt out
+// of this by setting the type explicitly.
+export const ordinalImplicit = Symbol("ordinal");
+
 export function ScaleO(scale, channels, {
   type,
   domain = inferDomain(channels),
   range,
   reverse,
   hint
 }) {
-  if (type === "categorical") type = "ordinal"; // shorthand for color schemes
+  if (type === "categorical" || type === ordinalImplicit) type = "ordinal"; // shorthand for color schemes
   if (reverse) domain = reverseof(domain);
   scale.domain(domain);
   if (range !== undefined) {
@@ -37,9 +43,11 @@ export function ScaleOrdinal(key, channels, {
     hint = inferSymbolHint(channels);
     range = range === undefined ? inferSymbolRange(hint) : Array.from(range, maybeSymbol);
   } else if (registry.get(key) === color) {
-    if (scheme === undefined
-        && range === undefined
-        && (range = maybeBooleanRange(domain, "greys")) === undefined) {
+    if (range === undefined && (type === "ordinal" || type === ordinalImplicit)) {
+      range = maybeBooleanRange(domain, scheme === undefined ? "greys" : scheme);
+      if (range !== undefined) scheme = undefined; // Don’t re-apply scheme.
+    }
+    if (scheme === undefined && range === undefined) {
       scheme = type === "ordinal" ? "turbo" : "tableau10";
     }
     if (scheme !== undefined) {