Enum validation

src/expression/definitions/assertion.ts

@@ -6,8 +6,9 @@
     NumberType,
     BooleanType,
     checkSubtype,
     typeToString,
-    array
+    array,
+    checkEnum
 } from '../types';
 import {RuntimeError} from '../runtime_error';
 import {typeOf} from '../values';
@@ -85,11 +86,11 @@
     evaluate(ctx: EvaluationContext) {
         for (let i = 0; i < this.args.length; i++) {
             const value = this.args[i].evaluate(ctx);
-            const error = checkSubtype(this.type, typeOf(value));
+            const error = checkSubtype(this.type, typeOf(value)) || checkEnum(this.type, value);
             if (!error) {
                 return value;
             } else if (i === this.args.length - 1) {
-                throw new RuntimeError(`Expected value to be of type ${typeToString(this.type)}, but found ${typeToString(typeOf(value))} instead.`);
+                throw new RuntimeError(error);
             }
         }
 

src/expression/definitions/format.ts

@@ -6,8 +6,9 @@
     StringType,
     ColorType,
     ResolvedImageType,
+    enumType,
 } from '../types';
 import {Formatted, FormattedSection, VERTICAL_ALIGN_OPTIONS, VerticalAlign} from '../types/formatted';
 import {valueToString, typeOf} from '../values';
 
 import type {Expression} from '../expression';
@@ -72,11 +73,7 @@
 
                 let verticalAlign = null;
                 if (arg['vertical-align']) {
-                    if (typeof arg['vertical-align'] === 'string' && !VERTICAL_ALIGN_OPTIONS.includes(arg['vertical-align'] as VerticalAlign)) {
-                        return context.error(`'vertical-align' must be one of: 'bottom', 'center', 'top' but found '${arg['vertical-align']}' instead.`) as null;
-                    }
-
-                    verticalAlign = context.parse(arg['vertical-align'], 1, StringType);
+                    verticalAlign = context.parse(arg['vertical-align'], 1, enumType(VERTICAL_ALIGN_OPTIONS));
                     if (!verticalAlign) return null;
                 }
 

src/expression/parsing_context.ts

@@ -118,7 +118,7 @@ export class ParsingContext {
                     //   * The "coalesce" operator, which needs to omit type annotations.
                     //   * String-valued properties (e.g. `text-field`), where coercion is more convenient than assertion.
                     //
-                    if ((expected.kind === 'string' || expected.kind === 'number' || expected.kind === 'boolean' || expected.kind === 'object' || expected.kind === 'array') && actual.kind === 'value') {
+                    if ((expected.kind === 'string' || expected.kind === 'number' || expected.kind === 'boolean' || expected.kind === 'object' || expected.kind === 'array' || expected.kind === 'enum') && actual.kind === 'value') {
                         parsed = annotate(parsed, expected, options.typeAnnotation || 'assert');
                     } else if ((expected.kind === 'projectionDefinition') && (actual.kind === 'string' || actual.kind === 'array')) {
                         parsed = annotate(parsed, expected, options.typeAnnotation || 'coerce');
@@ -128,6 +128,8 @@ export class ParsingContext {
                         parsed = annotate(parsed, expected, options.typeAnnotation || 'coerce');
                     } else if (expected.kind === 'variableAnchorOffsetCollection' && (actual.kind === 'value' || actual.kind === 'array')) {
                         parsed = annotate(parsed, expected, options.typeAnnotation || 'coerce');
+                    } else if (expected.kind === 'enum' && actual.kind === 'string') {
+                        parsed = annotate(parsed, expected, options.typeAnnotation || 'assert');
                     } else if (this.checkSubtype(expected, actual)) {
                         return null;
                     }

src/expression/types.ts

@@ -44,14 +44,19 @@ export type VariableAnchorOffsetCollectionTypeT = {
 export type EvaluationKind = 'constant' | 'source' | 'camera' | 'composite';
 
 export type Type = NullTypeT | NumberTypeT | StringTypeT | BooleanTypeT | ColorTypeT | ProjectionDefinitionTypeT | ObjectTypeT | ValueTypeT |
-ArrayType | ErrorTypeT | CollatorTypeT | FormattedTypeT | PaddingTypeT | ResolvedImageTypeT | VariableAnchorOffsetCollectionTypeT;
+ArrayType | ErrorTypeT | CollatorTypeT | FormattedTypeT | PaddingTypeT | ResolvedImageTypeT | VariableAnchorOffsetCollectionTypeT | EnumType;
 
 export interface ArrayType<T extends Type = Type> {
     kind: 'array';
     itemType: T;
     N: number;
 }
 
+export interface EnumType {
+    kind: 'enum';
+    values: readonly string[];
+}
+
 export type NativeType = 'number' | 'string' | 'boolean' | 'null' | 'array' | 'object';
 
 export const NullType = {kind: 'null'} as NullTypeT;
@@ -77,12 +82,21 @@ export function array<T extends Type>(itemType: T, N?: number | null): ArrayType
     };
 }
 
+export function enumType(values: readonly string[]): EnumType {
+    return {
+        kind: 'enum',
+        values
+    };
+}
+
 export function typeToString(type: Type): string {
     if (type.kind === 'array') {
         const itemType = typeToString(type.itemType);
         return typeof type.N === 'number' ?
             `array<${itemType}, ${type.N}>` :
             type.itemType.kind === 'value' ? 'array' : `array<${itemType}>`;
+    } else if (type.kind === 'enum') {
+        return `one of: ${type.values.map(v => `"${v}"`).join(', ')};`;
     } else {
         return type.kind;
     }
@@ -118,6 +132,8 @@ export function checkSubtype(expected: Type, t: Type): string {
             (typeof expected.N !== 'number' || expected.N === t.N)) {
             return null;
         }
+    } else if (expected.kind === 'enum' && t.kind === 'string') {
+        return null;
     } else if (expected.kind === t.kind) {
         return null;
     } else if (expected.kind === 'value') {
@@ -128,7 +144,14 @@ export function checkSubtype(expected: Type, t: Type): string {
         }
     }
 
-    return `Expected ${typeToString(expected)} but found ${typeToString(t)} instead.`;
+    return `Expected value to be of type ${typeToString(expected)}, but found ${typeToString(t)} instead.`;
+}
+
+export function checkEnum(expected: Type, value: unknown): string {
+    if (expected.kind === 'enum' && typeof value === 'string' && !expected.values.includes(value)) {
+        return `Expected ${typeToString(expected)} but found "${value}" instead.`;
+    }
+    return null;
 }
 
 export function isValidType(provided: Type, allowedTypes: Array<Type>): boolean {

test/integration/expression/tests/at/infer-array-type/test.json

@@ -28,7 +28,7 @@
       "errors": [
         {
           "key": "[2]",
-          "error": "Expected array<string> but found array<number, 3> instead."
+          "error": "Expected value to be of type array<string>, but found array<number, 3> instead."
         }
       ]
     }

test/integration/expression/tests/coalesce/argument-type-mismatch/test.json

@@ -24,7 +24,7 @@
       "errors": [
         {
           "key": "[2]",
-          "error": "Expected string but found number instead."
+          "error": "Expected value to be of type string, but found number instead."
         }
       ]
     }

test/integration/expression/tests/coalesce/infer-array-type/test.json

@@ -34,7 +34,7 @@
       "errors": [
         {
           "key": "[3]",
-          "error": "Expected array<string> but found null instead."
+          "error": "Expected value to be of type array<string>, but found null instead."
         }
       ]
     }

test/integration/expression/tests/format/data-driven-scale/test.json

@@ -31,7 +31,7 @@
       "errors": [
         {
           "key": "[1]",
-          "error": "Expected array<string> but found array instead."
+          "error": "Expected value to be of type array<string>, but found array instead."
         }
       ]
     }

test/integration/expression/tests/format/implicit-assert/test.json

@@ -23,7 +23,7 @@
       "errors": [
         {
           "key": "",
-          "error": "Expected formatted but found number instead."
+          "error": "Expected value to be of type formatted, but found number instead."
         }
       ]
     }

test/integration/expression/tests/format/unknown-vertical-align/test.json

@@ -11,8 +11,8 @@
       "result": "error",
       "errors": [
         {
-          "key": "",
-          "error": "'vertical-align' must be one of: 'bottom', 'center', 'top' but found 'unknown' instead."
+          "key": "[1]",
+          "error": "Expected one of: \"bottom\", \"center\", \"top\"; but found \"unknown\" instead."
         }
       ]
     }

test/integration/expression/tests/image/implicit-assert/test.json

@@ -23,7 +23,7 @@
       "errors": [
         {
           "key": "",
-          "error": "Expected resolvedImage but found number instead."
+          "error": "Expected value to be of type resolvedImage, but found number instead."
         }
       ]
     }

test/integration/expression/tests/match/mismatch-input/test.json

@@ -18,7 +18,7 @@
       "errors": [
         {
           "key": "[1]",
-          "error": "Expected number but found string instead."
+          "error": "Expected value to be of type number, but found string instead."
         }
       ]
     }

test/integration/expression/tests/match/mismatch-label-1/test.json

@@ -19,7 +19,7 @@
       "errors": [
         {
           "key": "[4]",
-          "error": "Expected string but found number instead."
+          "error": "Expected value to be of type string, but found number instead."
         }
       ]
     }

test/integration/expression/tests/match/mismatch-label-2/test.json

@@ -18,7 +18,7 @@
       "errors": [
         {
           "key": "[2]",
-          "error": "Expected string but found number instead."
+          "error": "Expected value to be of type string, but found number instead."
         }
       ]
     }

test/integration/expression/tests/match/mismatch-output/test.json

@@ -18,7 +18,7 @@
       "errors": [
         {
           "key": "[4]",
-          "error": "Expected string but found boolean instead."
+          "error": "Expected value to be of type string, but found boolean instead."
         }
       ]
     }

test/integration/expression/tests/match/mixed-type/test.json

@@ -53,7 +53,7 @@
       "errors": [
         {
           "key": "[4]",
-          "error": "Expected string but found number instead."
+          "error": "Expected value to be of type string, but found number instead."
         }
       ]
     }

test/integration/expression/tests/typecheck/array-invalid-item/test.json

@@ -27,7 +27,7 @@
       "errors": [
         {
           "key": "",
-          "error": "Expected array<string, 2> but found array<number, 2> instead."
+          "error": "Expected value to be of type array<string, 2>, but found array<number, 2> instead."
         }
       ]
     }

test/integration/expression/tests/typecheck/array-length-subtyping--no-length/test.json

@@ -26,7 +26,7 @@
       "errors": [
         {
           "key": "",
-          "error": "Expected array<number, 3> but found array<number> instead."
+          "error": "Expected value to be of type array<number, 3>, but found array<number> instead."
         }
       ]
     }

test/integration/expression/tests/typecheck/array-wrong-length/test.json

@@ -27,7 +27,7 @@
       "errors": [
         {
           "key": "",
-          "error": "Expected array<number, 3> but found array<number, 2> instead."
+          "error": "Expected value to be of type array<number, 3>, but found array<number, 2> instead."
         }
       ]
     }

test/integration/style-spec/tests/filters.output.json

@@ -44,7 +44,7 @@
     "line": 103
   },
   {
-    "message": "layers[12].filter[2]: Expected object but found string instead.",
+    "message": "layers[12].filter[2]: Expected value to be of type object, but found string instead.",
     "line": 131
   },
   {

test/integration/style-spec/tests/functions.output.json

@@ -164,11 +164,11 @@
     "line": 857
   },
   {
-    "message": "layers[47].paint.fill-color: Expected color but found number instead.",
+    "message": "layers[47].paint.fill-color: Expected value to be of type color, but found number instead.",
     "line": 898
   },
   {
-    "message": "layers[48].paint.fill-color[2]: Expected number but found string instead.",
+    "message": "layers[48].paint.fill-color[2]: Expected value to be of type number, but found string instead.",
     "line": 907
   },
   {

test/integration/style-spec/tests/text-field-format.output.json

@@ -8,15 +8,15 @@
     "line": 53
   },
   {
-    "message": "layers[6].layout.text-field[1]: Expected number but found string instead.",
+    "message": "layers[6].layout.text-field[1]: Expected value to be of type number, but found string instead.",
     "line": 99
   },
   {
     "message": "layers[7].layout.text-field[1][0]: Unknown expression \"Helvetica\". If you wanted a literal array, use [\"literal\", [...]].",
     "line": 111
   },
   {
-    "message": "layers[10].layout.text-field[1]: Expected array<string> but found number instead.",
+    "message": "layers[10].layout.text-field[1]: Expected value to be of type array<string>, but found number instead.",
     "line": 147
   }
 ]