An experimental TypeSpec syntax for Lexicon
feat: add enum constraint support
Map TypeSpec enums to Lexicon enum constraints:
- String enums: `enum Status { Active: "active" }` → `"enum": ["active", ...]`
- Integer enums: `enum Priority { Low: 1 }` → `"enum": [1, ...]`
Implementation:
- Detect Enum type in typeToLexiconDefinition
- Extract enum member values
- Determine if string or integer enum
- Emit primitive with enum field
Example:
```typespec
enum Priority { Low: 1, Medium: 2, High: 3 }
model Task { priority: Priority }
```
Emits:
```json
{
"priority": {
"type": "integer",
"enum": [1, 2, 3]
}
}
```
Tests: All 23 existing tests remain green (no fixtures changed)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
+40
+39
packages/emitter/src/emitter.ts
+39
packages/emitter/src/emitter.ts
···
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prop?: ModelProperty,
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): LexiconDefinition | null {
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switch (type.kind) {
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+
case "Enum": {
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// Handle enum types - convert to primitive with enum constraint
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const enumType = type as any;
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const members = Array.from(enumType.members?.values?.() || []);
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const values = members.map((m: any) => m.value);
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+
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// Determine if this is a string or integer enum
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const firstValue = values[0];
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const isStringEnum = typeof firstValue === "string";
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const isIntegerEnum = typeof firstValue === "number" && Number.isInteger(firstValue);
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+
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if (isStringEnum) {
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const primitive: LexiconPrimitive = {
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type: "string",
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enum: values as string[],
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};
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if (prop) {
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const propDesc = getDoc(this.program, prop);
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if (propDesc) {
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primitive.description = propDesc;
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}
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}
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return primitive;
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} else if (isIntegerEnum) {
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const primitive: LexiconPrimitive = {
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type: "integer",
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enum: values as number[],
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};
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if (prop) {
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const propDesc = getDoc(this.program, prop);
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if (propDesc) {
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primitive.description = propDesc;
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}
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}
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return primitive;
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}
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// Unsupported enum type (e.g., float)
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return null;
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}
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case "Boolean": {
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// Handle boolean literal types (e.g., `true` or `false`)
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const booleanType = type as any;