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1+++

2title = "3c: Urbit Time"

3weight = 23

4template = "doc.html"

5+++

7## `++yall`

9Time since beginning of time

11Produce the date tuple of `[y=@ud m=@ud d=@ud]` of the year, month, and

12day from a number of days from the beginning of the Gregorian calendar.

14#### Accepts

16`day` is a an unsigned decimal.

18#### Produces

20A cell of unsigned decimals.

22#### Source

24```hoon

25 ++ yall

26 |= day=@ud

27 ^- [y=@ud m=@ud d=@ud]

28 =+ [era=0 cet=0 lep=*?]

29 => .(era (div day era:yo), day (mod day era:yo))

30 => ^+ .

31 ?: (lth day +(cet:yo))

32 .(lep &, cet 0)

33 => .(lep |, cet 1, day (sub day +(cet:yo)))

34 .(cet (add cet (div day cet:yo)), day (mod day cet:yo))

35 =+ yer=(add (mul 400 era) (mul 100 cet))

36 |- ^- [y=@ud m=@ud d=@ud]

37 =+ dis=?:(lep 366 365)

38 ?. (lth day dis)

39 =+ ner=+(yer)

40 $(yer ner, day (sub day dis), lep =(0 (end 0 2 ner)))

41 |- ^- [y=@ud m=@ud d=@ud]

42 =+ [mot=0 cah=?:(lep moy:yo moh:yo)]

43 |- ^- [y=@ud m=@ud d=@ud]

44 =+ zis=(snag mot cah)

45 ?: (lth day zis)

46 [yer +(mot) +(day)]

47 $(mot +(mot), day (sub day zis))

48```

50#### Examples

52```

53 > (yall 198)

54 [y=0 m=7 d=17]

56 > (yall 90.398)

57 [y=247 m=7 d=3]

59 > (yall 0)

60 [y=0 m=1 d=1]

61```

63---

65## `++yawn`

67Days since beginning of time

69Inverse of `yall`, computes number of days A.D. from y/m/d date as the

70tuple `[yer=@ud mot=@ud day=@ud]`.

72#### Accepts

74`yer` is an unsigned decimal.

76`mon` is an unsigned decimal.

78`day` is an unsigned decimal.

80#### Produces

82An unsigned decimal.

84#### Source

86```hoon

87 ++ yawn

88 |= [yer=@ud mot=@ud day=@ud]

89 ^- @ud

90 => .(mot (dec mot), day (dec day))

91 => ^+ .

92 %= .

93 day

94 =+ cah=?:((yelp yer) moy:yo moh:yo)

95 |- ^- @ud

96 ?: =(0 mot)

97 day

98 $(mot (dec mot), cah (slag 1 cah), day (add day (snag 0 cah)))

99 ==

100 |- ^- @ud

101 ?. =(0 (mod yer 4))

102 =+ ney=(dec yer)

103 $(yer ney, day (add day ?:((yelp ney) 366 365)))

104 ?. =(0 (mod yer 100))

105 =+ nef=(sub yer 4)

106 $(yer nef, day (add day ?:((yelp nef) 1.461 1.460)))

107 ?. =(0 (mod yer 400))

108 =+ nec=(sub yer 100)

109 $(yer nec, day (add day ?:((yelp nec) 36.525 36.524)))

110 (add day (mul (div yer 400) (add 1 (mul 4 36.524))))

111```

112

113#### Examples

114

115```

116 > (yawn 2.018 7 4)

117 737.244

118

119 > (yawn 1.776 7 4)

120 648.856

121

122 > (yawn 1.990 10 11)

123 727.116

124```

126---

128## `++year`

130Date to @d

132Accept a parsed date of form `[[a=? y=@ud] m=@ud t=tarp]` and produce

133its `@d` representation.

135#### Accepts

137`det` is a `date`

139#### Produces

141A `@d`.

143#### Source

145```hoon

146 ++ year

147 |= det=date

148 ^- @da

149 =+ ^= yer

150 ?: a.det

151 (add 292.277.024.400 y.det)

152 (sub 292.277.024.400 (dec y.det))

153 =+ day=(yawn yer m.det d.t.det)

154 (yule day h.t.det m.t.det s.t.det f.t.det)

155```

156

157#### Examples

158

159```

160 > (year [[a=%.y y=2.014] m=8 t=[d=4 h=20 m=4 s=57 f=~[0xd940]]])

161 0x8000000d227df4e9d940000000000000

162```

163

164---

165

166## `++yell`

167

168Tarp from atomic date

169

170Produce a parsed daily time format from, `@d`, an atomic date.

172#### Accepts

174`now` is a `@d`.

176#### Produces

178A `tarp`.

180#### Source

182```hoon

183 ++ yell

184 |= now=@d

185 ^- tarp

186 =+ sec=(rsh 6 1 now)

187 =+ ^= fan

188 =+ [muc=4 raw=(end 6 1 now)]

189 |- ^- (list @ux)

190 ?: |(=(0 raw) =(0 muc))

191 ~

192 => .(muc (dec muc))

193 [(cut 4 [muc 1] raw) $(raw (end 4 muc raw))]

194 =+ day=(div sec day:yo)

195 => .(sec (mod sec day:yo))

196 =+ hor=(div sec hor:yo)

197 => .(sec (mod sec hor:yo))

198 =+ mit=(div sec mit:yo)

199 => .(sec (mod sec mit:yo))

200 [day hor mit sec fan]

201```

202

203#### Examples

204

205```

206 > (yell ~2014.3.20..05.42.53..7456)

207 [d=106.751.991.820.094 h=5 m=42 s=53 f=~[0x7456]]

208

209 > (yell ~2014.6.9..19.09.40..8b66)

210 [d=106.751.991.820.175 h=19 m=9 s=40 f=~[0x8b66]]

211

212 > (yell ~1776.7.4)

213 [d=106.751.991.733.273 h=0 m=0 s=0 f=~]

214```

216---

218## `++yelp`

220Leap-week?

222Determines whether a year contains an ISO 8601 leap-week. Produces a flag.

223

224#### Accepts

225

226`yer` is an unsigned decimal.

228#### Produces

230A flag.

232#### Source

234```hoon

235 ++ yelp

236 |= yer=@ud ^- ?

237 &(=(0 (mod yer 4)) |(!=(0 (mod yer 100)) =(0 (mod yer 400))))

238```

239

240#### Examples

241

242```

243 > (yelp 2.014)

244 %.n

245

246 > (yelp 2.008)

247 %.y

248

249 > (yelp 0)

250 %.y

251

252 > (yelp 14.011)

253 %.n

254```

255

256---

257

258## `++yore`

259

260Date from atomic date

261

262Produces a `date` from a `@d`.

263

264#### Accepts

265

266`now` is a time atom, `@d`.

268#### Produces

270A `date`.

272#### Source

274```hoon

275 ++ yore

276 |= now=@da

277 ^- date

278 =+ rip=(yell now)

279 =+ ger=(yall d.rip)

280 :- ?: (gth y.ger 292.277.024.400)

281 [a=& y=(sub y.ger 292.277.024.400)]

282 [a=| y=+((sub 292.277.024.400 y.ger))]

283 [m.ger d.ger h.rip m.rip s.rip f.rip]

284```

285

286#### Examples

287

288```

289 > (yore ~2014.6.6..21.09.15..0a16)

290 [[a=%.y y=2.014] m=6 t=[d=6 h=21 m=9 s=15 f=~[0xa16]]]

291```

292

293---

294

295## `++yule`

296

297Daily time to time atom

298

299Accepts a `tarp`, a parsed daily time, and produces a time atom,

300`@d`.

301

302#### Accepts

303

304`rip` is a `tarp`.

305

306#### Produces

307

308A time atom, `@d`.

309

310#### Source

311

312```hoon

313 ++ yule :: time atom

314 |= rip=tarp

315 ^- @d

316 =+ ^= sec ;: add

317 (mul d.rip day:yo)

318 (mul h.rip hor:yo)

319 (mul m.rip mit:yo)

320 s.rip

321 ==

322 =+ ^= fac =+ muc=4

323 |- ^- @

324 ?~ f.rip

325 0

326 => .(muc (dec muc))

327 (add (lsh 4 muc i.f.rip) $(f.rip t.f.rip))

328 (con (lsh 6 1 sec) fac)

329 ::

330```

331

332#### Examples

333

334```

335 > =murica (yell ~1776.7.4)

336

337 > murica

338 [d=106.751.991.733.273 h=0 m=0 s=0 f=~]

339

340 > (yule murica)

341 0x8000000b62aaf5800000000000000000

342

343 > `@da`(yule murica)

344 ~1776.7.4

345

346 > `@da`(yule (yell ~2014.3.20..05.42.53..7456))

347 ~2014.3.20..05.42.53..7456

348

349 > `tarp`[31 12 30 0 ~]

350 [d=31 h=12 m=30 s=0 f=~]

351

352 > `@dr`(yule `tarp`[31 12 30 0 ~])

353 ~d31.h12.m30

354```

355

356---

357

358## `++yo`

359

360Time constants core

361

362Core whose arms contain constants for interacting with earth time.

363

364#### Source

365

366```hoon

367 ++ yo

368```

370---

372### `++cet:yo`

374Days in a century

376Derived by multiplying the number of days in a year

377(365) by the number of years in a century (100), then adding the number

378days from leap-years in a century (24).

380#### Produces

382An atom.

384#### Source

386```hoon

387 |% ++ cet 36.524

388```

389

390#### Examples

391

392```

393 > cet:yo

394 36.524

395

396 > (add 365 cet:yo)

397 36.889

398

399 > (sub (add 24 (mul 100 365)) cet:yo)

400 0

401```

403---

405### `++day:yo`

407Seconds in day

409The number of seconds in a day.

411#### Produces

413An atom.

415#### Source

417```hoon

418 ++ day 86.400

419```

420

421#### Examples

422

423```

424 > day:yo

425 86.400

426

427 > (add 60 day:yo)

428 86.460

429```

431---

433### `++era:yo`

435Leap-year period

437The number of days in a 400-year period, arrived at by multiplying `cet` by four

438and adding one. This is done because every 400 years, there is a leap-year where

439there would otherwise not be.

441#### Produces

443An atom.

445#### Source

447```hoon

448 ++ era 146.097

449```

450

451#### Examples

452

453```

454 > era:yo

455 146.097

456

457 > (sub era:yo (mul 4 cet:yo))

458 1

459```

460

461#### Discussion

462

463A year is a leap-year if:

464

465- it's divisible by 4;

466- **unless** it's divisible by 100;

467- **or** if it's divisible by 400.

469---

471### `++hor:yo`

473Seconds in hour

475The number of seconds in an hour. Derived by multiplying the number of

476seconds in a minute by the minutes in an hour.

478#### Produces

480An atom.

482#### Source

484```hoon

485 ++ hor 3.600

486```

487

488#### Examples

489

490```

491 > hor:yo

492 3.600

493

494 > (div hor:yo 60)

495 60

496```

497

498---

499

500### `++jes:yo`

501

502Maximum 64-bit timestamp

503

504This is the number of days (starting from 1970) that can be represented in a

50564-bit timestamp. Derived by multiplying `era:yo` by 730,692,561.

507#### Produces

509An atom.

511#### Source

513```hoon

514 ++ jes 106.751.991.084.417

515```

516

517#### Examples

518

519```

520 > jes:yo

521 106.751.991.084.417

522```

523

524#### Discussion

525

526The date is December 4, 292,277,026,596.

528---

530### `++mit:yo`

532Seconds in minute

534The number of seconds in a minute.

536#### Produces

538An atom.

540#### Source

542```hoon

543 ++ mit 60

544```

545

546#### Examples

547

548```

549 > mit:yo

550 60

551```

553---

555### `++moh:yo`

557Days in month

559The days in each month of the Gregorian common year. A list of unsigned

560decimal atoms (Either 28, 30, or 31) denoting the number of days in the

561month at the year at that index.

563#### Produces

565A `list` of `@ud`

567#### Source

569```hoon

570 ++ moh `(list @ud)`[31 28 31 30 31 30 31 31 30 31 30 31 ~]

571```

572

573#### Examples

574

575```

576 > moh:yo

577 ~[31 28 31 30 31 30 31 31 30 31 30 31]

578

579 > (snag 4 moh:yo)

580 31

581```

582

583---

584

585### `++moy:yo`

586

587Days in months of leap-year

588

589The days in each month of the Gregorian leap-year. A list of unsigned

590decimal atoms (Either 29, 30, or 31) denoting the number of days in the

591month at the leap-year at that index.

592

593#### Produces

594

595A `list` of `@ud`.

596

597#### Source

598

599```hoon

600 ++ moy `(list @ud)`[31 29 31 30 31 30 31 31 30 31 30 31 ~]

601```

602

603#### Examples

604

605```

606 > moy:yo

607 ~[31 29 31 30 31 30 31 31 30 31 30 31]

608

609 > (snag 1 moy:yo)

610 29

611```

612

613---

614

615### `++qad:yo`

616

617Seconds in 4 years

618

619The number of seconds in four years. Derived by adding one second to the

620number of seconds in four years.

622#### Produces

624An atom.

626#### Source

628```hoon

629 ++ qad 126.144.001

630```

631

632#### Examples

633

634```

635 > qad:yo

636 126.144.001

637```

639---

641### `++yer:yo`

643Seconds in year

645The number of seconds in a year. Derived by multiplying the number of

646seconds in a day by 365.

648#### Produces

650An atom.

652#### Source

654```hoon

655 ++ yer 31.536.000

656```

657

658#### Examples

659

660```

661 > yer:yo

662 31.536.000

663```

664

665---