preserves/implementations/javascript/packages/schema/src/compiler/type.ts

90 lines
3.2 KiB
TypeScript

import { anglebrackets, braces, Item, keyvalue, opseq, seq } from "./block";
export type Type =
| { kind: 'union', variants: VariantMap } // zero: never
| SimpleType
export type SimpleType = AtomicType | CompoundType
export type FieldType = AtomicType | CollectionType;
export type AtomicType =
| { kind: 'unit' }
| { kind: 'ref', typeName: string } // also for base types
export type CompoundType =
| CollectionType
| { kind: 'record', fields: FieldMap }
export type CollectionType =
| { kind: 'array', type: AtomicType }
| { kind: 'set', type: AtomicType }
| { kind: 'dictionary', key: AtomicType, value: AtomicType }
export type VariantMap = Map<string, SimpleType>;
export type FieldMap = Map<string, FieldType>;
export namespace Type {
export const union = (variants: VariantMap): Type => ({ kind: 'union', variants });
export const unit = (): AtomicType => ({ kind: 'unit' });
export const ref = (typeName: string): AtomicType => ({ kind: 'ref', typeName });
export const record = (fields: FieldMap): CompoundType => ({ kind: 'record', fields });
export const array = (type: AtomicType): CollectionType => ({ kind: 'array', type });
export const set = (type: AtomicType): CollectionType => ({ kind: 'set', type });
export const dictionary = (key: AtomicType, value: AtomicType): CollectionType => (
{ kind: 'dictionary', key, value });
}
export const ANY_TYPE: AtomicType = Type.ref('_val');
export function variantInitFor(variantName: string | undefined) : Item[] {
return variantName === void 0 ? [] : [variantFor(variantName)];
}
export function variantFor(variantName: string): Item {
return keyvalue('_variant', JSON.stringify(variantName));
}
export function renderVariant([variantName, t]: [string, SimpleType]): Item {
let fields: Item[];
switch (t.kind) {
case 'unit':
fields = [];
break;
case 'ref':
case 'set':
case 'dictionary':
case 'array':
fields = [keyvalue('value', renderType(t))];
break;
case 'record':
fields = Array.from(t.fields).map(([nn, tt]) => keyvalue(nn, renderType(tt)));
break;
default:
((_: never) => {})(t);
throw new Error("Unreachable");
}
return braces(variantFor(variantName), ... fields);
}
export function renderType(t: Type): Item {
switch (t.kind) {
case 'union': return opseq('never', ' | ', ...
Array.from(t.variants).flatMap(renderVariant));
case 'unit': return 'null';
case 'ref': return t.typeName;
case 'set': return seq('_.KeyedSet', anglebrackets(
renderType(t.type),
'_embedded'));
case 'dictionary': return seq('_.KeyedDictionary', anglebrackets(
renderType(t.key),
renderType(t.value),
'_embedded'));
case 'array': return seq('Array', anglebrackets(renderType(t.type)));
case 'record': return braces(... Array.from(t.fields).map(([nn, tt]) =>
keyvalue(nn, renderType(tt))));
default:
((_: never) => {})(t);
throw new Error("Unreachable");
}
}