parse: improved da support

Support leading zeroes in timeslots, absence of time and/or subseconds,
and negative years (Before Christ).

Author: Fang-

src/da.ts

@@ -93,13 +93,20 @@ export function year(det: Dat) {
  * @return  {bigint}      x  The urbit date as bigint
  */
 export function parseDa(x: string): bigint {
-  const [date, time, ms] = x.split('..');
-  const [yer, month, day] = date.slice(1).split('.');
+  let pos = true;
+  let [date, time, ms] = x.split('..');
+  time = time || '0.0.0';
+  ms = ms || '0000';
+  let [yer, month, day] = date.slice(1).split('.');
+  if (yer.at(-1) === '-') {
+    yer = yer.slice(0, -1);
+    pos = false;
+  }
   const [hour, minute, sec] = time.split('.');
   const millis = ms.split('.').map((m) => BigInt('0x'+m));
 
   return year({
-    pos: true,
+    pos: pos,
     year: BigInt(yer),
     month: BigInt(month),
     time: {

src/parse.ts

@@ -48,7 +48,7 @@ export type coin = ({ type: 'dime' } & dime)
 //TODO  rewrite with eye towards capturing groups?
 export const regex: { [key in aura]: RegExp } = {
   'c':   /^~\-((~[0-9a-fA-F]+\.)|(~[~\.])|[0-9a-z\-\._])*$/,
-  'da':  /^~(0|[1-9][0-9]*)\-?\.([1-9]|1[0-2])\.([1-9]|[1-3][0-9])(\.\.(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)(\.(\.[0-9a-f]{4})+)?)?$/,
+  'da':  /^~(0|[1-9][0-9]*)\-?\.([1-9]|1[0-2])\.([1-9]|[1-3][0-9])(\.\.([0-9]+)\.([0-9]+)\.([0-9]+)(\.(\.[0-9a-f]{4})+)?)?$/,
   'dr':  /^~((d|h|m|s)(0|[1-9][0-9]*))(\.(d|h|m|s)(0|[1-9][0-9]*))?(\.(\.[0-9a-f]{4})+)?$/,
   'f':   /^\.(y|n)$/,
   'n':   /^~$/,

test/parse.test.ts

@@ -307,11 +307,14 @@ const DATE_TESTS: {
   { 'n': 170141184492616163062707000439658774528n,
     'da': '~2000.1.1..11.11.11..aabb.0000'
   },
+  { 'n': 170141184492616163062707000439658774528n,
+    'da': '~2000.1.1..11.11.11..aabb'
+  },
   { 'n': 170141184492615487727406687186543706111n,
     'da': '~2000.1.1..1.1.1..aabb.ccdd.eeff.ffff'
   }
 ];
-testAuras('phonetic', DATE_AURAS, DATE_TESTS);
+testAuras('date', DATE_AURAS, DATE_TESTS);
 
 describe('string decoding', () => {
   it('decodes', () => {