docs/reference/library/1a.udon · urbit.org

git.iko.soy/urbit.org

on c19bc7a help sign in

urbit.org/docs/reference/library/1a.udon

684 lines 6.7 kB history raw

1:- :~ navhome/'/docs/'

2 sort/'1'

3 title/'1a: Basic Arithmetic'

4 ==

6;>

9# 1a: basic arithmetic

11### `++add`

13Add

15Produces the sum of `a` and `b`.

17#### Accepts

19`a` is an atom.

21`b` is an atom.

23#### Produces

25An atom.

27#### Source

29```

30 ++ add

31 ~/ %add

32 |= [a=@ b=@]

33 ^- @

34 ?: =(0 a) b

35 $(a (dec a), b +(b))

36```

38#### Examples

40```

41 > (add 2 2)

42 4

44 > (add 1 1.000.000)

45 1.000.001

47 > (add 1.333 (mul 2 2))

48 1.337

50 > (add 'a' 4)

51 101

53 > (add 'a' 'b')

54 195

56 > (add 0xc 0xf)

57 27

59 > `@ux`(add 0xc 0xf)

60 0x1b

61```

63---

64### `++dec`

66Decrement

68Decrements `a` by `1`.

70#### Accepts

72`a` is an atom.

74#### Produces

76An atom.

78#### Source

80```

81 ++ dec

82 ~/ %dec

83 |= a=@

84 ~| %decrement-underflow

85 ?< =(0 a)

86 =+ b=0

87 |- ^- @

88 ?: =(a +(b)) b

89 $(b +(b))

90```

92#### Examples

94```

95 > (dec 7)

96 6

98 > (dec 0)

99 ! decrement-underflow

100 ! exit

101

102 > (dec 'b')

103 97

104 > `@t`(dec 'b')

105 'a'

106

107 > (dec 0xc)

108 11

109 > `@ux`(dec 0xc)

110 0xb

111```

112

113

114---

115### `++div`

116

117Divide

118

119Computes `a` divided by `b` without remainder.

121#### Accepts

123`a` is an atom.

125`b` is an atom.

127#### Produces

129An atom.

131#### Source

133```

134 ++ div

135 ~/ %div

136 |: [a=`@`1 b=`@`1]

137 ^- @

138 ~_ leaf+"divide-by-zero"

139 ?< =(0 b)

140 =+ c=0

141 |-

142 ?: (lth a b) c

143 $(a (sub a b), c +(c))

144```

145

146#### Examples

147

148```

149 > (div 4 2)

150 2

151

152 > (div 17 8)

153 2

154

155 > (div 20 30)

156 0

157

158 > (div 'ab' 'a')

159 259

160 > `@`'ab'

161 25.185

162 > `@`a

163 97

164

165 > (div 0x9f 0x29)

166 6

167```

168

169---

170### `++dvr`

171

172Divide with remainder

173

174Computes `a` divided by `b`, producing the quotient and the remainder.

176#### Accepts

178`a` is an atom.

180`b` is an atom.

182#### Produces

184A cell of atoms.

186#### Source

188```

189 ++ dvr

190 ~/ %dvr

191 |= [a=@ b=@]

192 ^- [p=@ q=@]

193 [(div a b) (mod a b)]

194```

195

196#### Examples

197

198```

199 > (dvr 17 8)

200 [p=2 q=1]

201

202 > (dvr 17 6)

203 [p=2 q=5]

204

205 > (dvr 18 6)

206 [p=3 q=0]

207

208 > (dvr 4 2)

209 [p=2 q=0]

210

211 > (dvr 'ab 'a')

212 [p=259 q=62]

213 > `@`'a'

214 97

215 > `@`'ab'

216 25.185

217```

218

219---

220### `++gte`

221

222Greater-than/equal

223

224Tests whether `a` is greater than or equal to `b`.

226#### Accepts

228`a` is an atom.

230`b` is an atom.

232#### Produces

234A flag.

236#### Source

238```

239 ++ gte

240 ~/ %gte

241 |= [a=@ b=@]

242 ^- ?

243 !(lth a b)

244```

245

246#### Examples

247

248```

249 > (gte 100 10)

250 %.y

251

252 > (gte 4 4)

253 %.y

254

255 > (gte 3 4)

256 %.n

257```

258

259---

260### `++gth`

261

262Greater-than

263

264Tests whether `a` is greater than `b`.

266#### Accepts

268`a` is an atom.

270`b` is an atom.

272#### Produces

274A flag.

276#### Source

278```

279 ++ gth

280 ~/ %gth

281 |= [a=@ b=@]

282 ^- ?

283 !(lte a b)

284```

285

286

287#### Examples

288

289```

290 > (gth 'd' 'c')

291 %.y

292

293 > (gth ~h1 ~m61)

294 %.n

295

296 > (gth 'steak' 'brisket')

297 %.n

298```

299

300---

301### `++lte`

302

303Less-than/equal

304

305Tests whether `a` is less than or equal to `b`.

307#### Accepts

309`a` is an atom.

311`b` is an atom.

313#### Produces

315A flag.

317#### Source

319```

320 ++ lte

321 ~/ %lte

322 |= [a=@ b=@]

323 |(=(a b) (lth a b))

324```

325

326#### Examples

327

328```

329 > (lte 4 5)

330 %.y

331

332 > (lte 5 4)

333 %.n

334

335 > (lte 5 5)

336 %.y

337

338 > (lte 0 0)

339 %.y

340

341

342 > (lte 'a' 'b')

343 %.y

344 > `@`'a'

345 97

346 > `@`'b'

347 98

348

349 > (lte 'abraham' 'bob')

350 %.n

351

352 > (lte ~m61 ~h1)

353 %.n

354```

355

356

357---

358### `++lth`

359

360Less-than

361

362Tests whether `a` is less than `b`.

364#### Accepts

366`a` is an atom.

368`b` is an atom.

370#### Produces

372A flag.

374#### Source

376```

377 ++ lth

378 ~/ %lth

379 |= [a=@ b=@]

380 ^- ?

381 ?& !=(a b)

382 |-

383 ?| =(0 a)

384 ?& !=(0 b)

385 $(a (dec a), b (dec b))

386 == == ==

387```

388

389#### Examples

390

391```

392 > (lth 4 5)

393 %.y

394

395 > (lth 5 4)

396 %.n

397

398 > (lth 5 5)

399 %.n

400

401 > (lth 5 0)

402 %.n

403

404 > (lth 'a' 'b')

405 %.y

406 > `@`'a'

407 97

408 > `@`'b'

409 98

410

411 > (lth 'abraham' 'bob')

412 %.n

413```

414

415---

416### `++max`

417

418Maximum

419

420Computes the greater of `a` and `b`.

422#### Accepts

424`a` is an atom.

426`b` is an atom.

428#### Produces

430An atom.

432#### Source

434```

435 ++ max

436 ~/ %max

437 |= [a=@ b=@]

438 ^- @

439 ?: (gth a b) a

440 b

441```

442

443#### Examples

444

445```

446 > (max 10 100)

447 100

448

449 > (max 10.443 9)

450 10.443

451

452 > (max 1 1)

453 1

454

455 > (max 'abraham' 'bob')

456 30.787.873.400.840.801

457

458 > `@t`(max 'abraham' 'bob')

459 'abraham'

460

461 > `@t`(max 'abraham' 'benjamin')

462 'benjamin'

463

464 > `@dr`(max ~m6 ~h1)

465 ~h1

466

467 >`@ux`(max 0xe1 0x1e)

468 0xe1

469```

470

471---

472### `++min`

473

474Minimum

475

476Computes the lesser of `a` and `b`.

478#### Accepts

480`a` is an atom.

482`b` is an atom.

484#### Produces

486An atom.

488#### Source

490```

491 ++ min

492 ~/ %min

493 |= [a=@ b=@]

494 ^- @

495 ?: (lth a b) a

496 b

497```

498

499#### Examples

500

501```

502 > (min 10 100)

503 10

504

505 > (min 10.443 9)

506 9

507

508 > (min 1 1)

509 1

510

511 > (min 'abraham' 'bob')

512 6.451.042

513

514 > `@t`(min 'abraham' 'bob')

515 'bob'

516

517 > `@t`(min 'abraham' 'benjamin')

518 'abraham'

519

520 > `@dr`(min ~m6 ~h1)

521 ~m6

522```

523

524

525---

526### `++mod`

527

528Modulus

529

530Computes the remainder of dividing `a` by `b`.

532#### Accepts

534`a` is an atom.

536`b` is an atom.

538#### Produces

540An atom.

542#### Source

544```

545 ++ mod

546 ~/ %mod

547 |: [a=`@`1 b=`@`1]

548 ^- @

549 ?< =(0 b)

550 (sub a (mul b (div a b)))

551```

552

553#### Examples

554

555```

556 > (mod 5 2)

557 1

558

559 > (mod 5 5)

560 0

561

562 > (mod 2 5)

563 2

564

565 > (mod 40 20)

566 0

567

568 > `@`'c'

569 99

570 >`@`'a'

571 97

572 > (mod 'c' 'a')

573 2

574```

575

576---

577### `++mul`

578

579Multiply

580

581Multiplies `a` by `b`.

583#### Accepts

585`a` is an atom.

587`b` is an atom.

589#### Produces

591An atom.

593#### Source

595```

596 ++ mul

597 ~/ %mul

598 |: [a=`@`1 b=`@`1]

599 ^- @

600 =+ c=0

601 |-

602 ?: =(0 a) c

603 $(a (dec a), c (add b c))

604```

605

606#### Examples

607

608```

609 > (mul 3 4)

610 12

611

612 > (mul 0 1)

613 0

614

615 > `@`'a'

616 97

617 > `@`'b'

618 98

619 > (mul 'a' 'b')

620 9.506

621

622 >`@ux`(mul 0x1f 0xe)

623 0x1b2

624```

625

626

627---

628### `++sub`

629

630Subtract

631

632Subtracts `b` from `a`.

634#### Accepts

636`a` is an atom.

638`b` is an atom.

640#### Produces

642An atom.

644#### Source

646```

647 ++ sub

648 ~/ %sub

649 |= [a=@ b=@]

650 ~_ leaf+"subtract-underflow"

651 ^- @

652 ?: =(0 b) a

653 $(a (dec a), b (dec b))

654```

655

656

657#### Examples

658

659```

660 > (sub 10 5)

661 5

662

663 > (sub 243 44)

664 199

665

666 > (sub 5 0)

667 5

668

669 > (sub 0 5)

670 ! subtract-underflow

671 ! exit

672

673 > (sub 'c' 'a')

674 2

675 > `@`'c'

676 99

677 > `@`'a'

678 97

679

680 > (sub 0x1f 0xe)

681 17

682 > `@ux`(sub 0x1f 0xe)

683 0x11

684```