Change signature for Property pattern helpers

lib/idv.ts

@@ -1,5 +1,6 @@
 export type DistinguisherParser<T> = (distinguisher: string) => T;
 export type DocumentParser<T> = (document: string[]) => T;
+export type UnionParser<T> = (distinguisher: string, document: string[]) => T;
 export type IdvConverter<T> = (idv: Idv) => T;
 
 const LEADING_WHITESPACE = /^([ \t]+)/;
@@ -58,6 +59,7 @@ export class Idv {
 
           currentDocument = [];
           currentIndent = undefined;
+          // TODO: implement backslash escaping in the distinguisher
           this.collections[collection].push([distinguisher, currentDocument]);
         } else {
           throw new Error("Failed to parse a property");
@@ -68,29 +70,14 @@ export class Idv {
     return this;
   }
 
-  public getProperty<T>(
-    name: string,
-    parseDistinguisher: DistinguisherParser<T>,
-    parseDocument: DocumentParser<T>
-  ): T | undefined {
+  public getProperty<T>(name: string, parse: UnionParser<T>): T | undefined {
     const firstEntry = this.collections[name]?.[0];
-    return (
-      firstEntry &&
-      (firstEntry[1].length > 0
-        ? parseDocument(firstEntry[1])
-        : parseDistinguisher(firstEntry[0]))
-    );
+    return firstEntry && parse(firstEntry[0], firstEntry[1]);
   }
 
-  public getList<T>(
-    name: string,
-    parseDistinguisher: DistinguisherParser<T>,
-    parseDocument: DocumentParser<T>
-  ): T[] {
+  public getList<T>(name: string, parse: UnionParser<T>): T[] {
     return (this.collections[name] ?? []).map(([distinguisher, document]) =>
-      document.length > 0
-        ? parseDocument(document)
-        : parseDistinguisher(distinguisher)
+      parse(distinguisher, document)
     );
   }
 
@@ -131,4 +118,6 @@ export class Idv {
   }
 }
 
-export const StringFromDocument = (lines: string[]) => lines.join("\n");
+// TODO: implement backslash-escaping in the document?
+export const StringProperty = (distinguisher: string, lines: string[]) =>
+  lines.length == 0 ? distinguisher : lines.join("\n");