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Merged
merged 8 commits into from
Apr 8, 2023
Merged

add toInt and toNumber #7

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5f7b20f
add toInt and toNumber
gbagan Mar 23, 2023
669726c
Add documentation for toNumber and toInt
gbagan Apr 4, 2023
4b2ed9f
Update src/JS/BigInt.purs
gbagan Apr 4, 2023
d92ba70
Update src/JS/BigInt.purs
gbagan Apr 4, 2023
c2aa371
Update src/JS/BigInt.purs
gbagan Apr 4, 2023
ff2ffe2
Update src/JS/BigInt.purs
gbagan Apr 4, 2023
7fea71c
Update BigInt.purs
gbagan Apr 4, 2023
7a94ab2
Update package.json
f-f Apr 8, 2023
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2 changes: 2 additions & 0 deletions src/JS/BigInt.js
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Expand Up @@ -19,6 +19,8 @@ export const fromInt = (n) => BigInt(n);

export const fromTypeLevelInt = (str) => BigInt(str);

export const toNumber = (n) => Number(n);
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Shouldn't this check whether n is in range?

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I'm not quite sure about this point but I think checking is not necessary because Number() returns +infinity or -infinity (which are valid Purescript numbers) if the bounds are not checked.
By the way, no function in Data.Number (like pow or acos) does checking.
Neither does purescript-bigints' toNumber function.

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I think it's okay to return +infinity or -infinity but that should be documented. The toNumber export should say “If the BigInt is too positive then the result will be +Infinity. If the BigInt is too negative, then the result will be -Infinity.” or something like that.


export const biAdd = (x) => (y) => x + y;

export const biMul = (x) => (y) => x * y;
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13 changes: 13 additions & 0 deletions src/JS/BigInt.purs
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Expand Up @@ -4,6 +4,8 @@ module JS.BigInt
, fromNumber
, fromString
, fromTLInt
, toInt
, toNumber
, asIntN
, asUintN
, toString
Expand All @@ -24,6 +26,7 @@ module JS.BigInt
import Prelude

import Data.Int (Parity(..), Radix)
import Data.Int as Int
import Data.Int (Parity(..), Radix, binary, octal, decimal, hexadecimal) as Exports
import Data.Maybe (Maybe(..))
import Data.Reflectable (class Reflectable, reflectType)
Expand Down Expand Up @@ -79,6 +82,16 @@ foreign import fromTypeLevelInt ∷ String → BigInt
fromTLInt ∷ ∀ i sym. ToString i sym ⇒ Reflectable sym String ⇒ Proxy i → BigInt
fromTLInt _ = fromTypeLevelInt (reflectType (Proxy ∷ Proxy sym))

-- | Convert a `BigInt` to a `Number`.
-- | There may be a loss of precision.
-- | If the `BigInt` is too large then the result will be `+Infinity`. If the `BigInt` is too small (too negative) then the result will be `-Infinity`.
foreign import toNumber ∷ BigInt → Number

-- | Convert a `BigInt` to an `Int`.
-- | The `BigInt` must fall within the valid range of values for the `Int` type otherwise `Nothing` is returned.
toInt ∷ BigInt → Maybe Int
toInt = toNumber >>> Int.fromNumber

foreign import biAdd ∷ BigInt → BigInt → BigInt
foreign import biMul ∷ BigInt → BigInt → BigInt

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17 changes: 7 additions & 10 deletions test/Main.purs
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@@ -1,12 +1,13 @@
module Test.Main where

import Prelude
import Data.Array.NonEmpty (cons')
import Data.Foldable (fold)
import Data.Maybe (Maybe(..), fromMaybe)
import Debug (spy)
import Effect (Effect)
import Effect.Console (log)
import Js.BigInt.BigInt (BigInt, and, fromInt, fromString, fromTLInt, not, or, pow, shl, shr, toString, xor, even, odd, parity, toStringAs, binary, octal)
import JS.BigInt (BigInt, and, fromInt, fromString, fromTLInt, not, or, pow, shl, shr, toString, xor, even, odd, parity, toInt, toStringAs, binary, octal)
import Prelude (class CommutativeRing, class Eq, class EuclideanRing, class Ord, class Ring, class Semiring, Unit, bind, compare, discard, identity, map, mod, negate, one, pure, show, zero, ($), (*), (+), (-), (/), (<$>), (<<<), (==))
import Test.Assert (assert)
import Test.QuickCheck (quickCheck)
Expand Down Expand Up @@ -127,15 +128,11 @@ main = do
-- Data.checkEuclideanRing prxBigInt

log "Converting BigInt to Int"
-- assert $ (fromString "0" <#> asIntN 64) == Just 0
-- assert $ (fromString "2137" <#> asIntN 64) == Just 2137
-- assert $ (fromString "-2137" <#> asIntN 64) == Just (-2137)
-- assert $ (fromString "2147483647" <#> asIntN 64) == Just 2147483647
-- assert $ (fromString "2147483648" <#> asIntN 64) == Nothing
-- assert $ (fromString "-2147483648" <#> asIntN 64) == Just (-2147483648)
-- assert $ (fromString "-2147483649" <#> asIntN 64) == Nothing
-- assert $ (fromString "921231231322337203685124775809" <#> asIntN 64) == Nothing
-- assert $ (fromString "-922337203612312312312854775809" <#> asIntN 64) == Nothing
assert $ (fromString "0" >>= toInt) == Just 0
assert $ (fromString "2137" >>= toInt) == Just 2137
assert $ (fromString "-2137" >>= toInt) == Just (-2137)
assert $ (fromString "921231231322337203685124775809" >>= toInt) == Nothing
assert $ (fromString "-922337203612312312312854775809" >>= toInt) == Nothing
-- quickCheck (\a b c ->
-- let x = add (fromInt a) (add (fromInt b) (fromInt c))
-- in case asIntN 64 x of
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