Add more proper typing

* Require _is and _typeHierarchy
* Add interfaces for TypeSpecifier structures

src/cql-patient.ts

@@ -1,5 +1,5 @@
 import * as DT from './datatypes/datatypes';
-import { DataProvider, PatientObject, RecordObject } from './types';
+import { DataProvider, NamedTypeSpecifier, PatientObject, RecordObject } from './types';
 
 export class Record implements RecordObject {
   json: any;
@@ -16,7 +16,7 @@ export class Record implements RecordObject {
     );
   }
 
-  _typeHierarchy() {
+  _typeHierarchy(): NamedTypeSpecifier[] {
     return [
       {
         name: `{https://github.com/cqframework/cql-execution/simple}${this.json.recordType}`,

src/types/cql-patient.interfaces.ts

@@ -1,3 +1,5 @@
+import { AnyTypeSpecifier } from './type-specifiers.interfaces';
+
 /*
  * Iterator for the patients provided to the execution engine
  */
@@ -15,11 +17,13 @@ export interface RecordObject {
   getCode(field: any): any;
   getDate(field: any): any;
   getDateOrInterval(field: any): any;
+  _is?(typeSpecifier: any): boolean;
+  _typeHierarchy?(): AnyTypeSpecifier[];
 }
 
 /*
  * Patient data object that implements logic for searching for records based on the Patient
  */
-export interface PatientObject {
+export interface PatientObject extends RecordObject {
   findRecords(profile: string | null): RecordObject[];
 }

src/types/index.ts

@@ -1,3 +1,4 @@
-export * from './runtime.types';
 export * from './cql-code-service.interfaces';
 export * from './cql-patient.interfaces';
+export * from './runtime.types';
+export * from './type-specifiers.interfaces';

src/types/type-specifiers.interfaces.ts

@@ -0,0 +1,50 @@
+// Types derived from http://cql.hl7.org/04-logicalspecification.html#typespecifier
+
+/*
+ * Utility type for any possible TypeSpecifier
+ */
+export type AnyTypeSpecifier =
+  | NamedTypeSpecifier
+  | IntervalTypeSpecifier
+  | ListTypeSpecifier
+  | TupleTypeSpecifier
+  | ChoiceTypeSpecifier;
+
+/*
+ * Base interface for other TypeSpecifiers to extend from
+ */
+export interface TypeSpecifier {
+  type: string;
+  localId?: string;
+}
+
+export interface NamedTypeSpecifier extends TypeSpecifier {
+  type: 'NamedTypeSpecifier';
+  name: string;
+}
+
+export interface IntervalTypeSpecifier extends TypeSpecifier {
+  type: 'IntervalTypeSpecifier';
+  pointType: AnyTypeSpecifier;
+}
+
+export interface ListTypeSpecifier extends TypeSpecifier {
+  type: 'ListTypeSpecifier';
+  elementType: AnyTypeSpecifier;
+}
+
+export interface TupleElementDefinition {
+  localId?: string;
+  name: string;
+  elementType: AnyTypeSpecifier;
+}
+
+export interface TupleTypeSpecifier extends TypeSpecifier {
+  type: 'TupleTypeSpecifier';
+  element?: TupleElementDefinition[];
+}
+
+export interface ChoiceTypeSpecifier extends TypeSpecifier {
+  type: 'ChoiceTypeSpecifier';
+  choice?: AnyTypeSpecifier[];
+}