Use BigInt instead of Int (#42)

Author: gbagan

README.md

@@ -40,12 +40,8 @@ bower install purescript-rationals
 
 ## Other Ratios
 
-`Rational` is just a type alias for `Ratio Int` and you might want to use
-`Ratio` with other than `Int`. The type you choose must however be an `EuclideanRing`.
-
-For example, one limitation with `Rational` is that it can easily overflow
-the 32-bit PureScript `Int`. You can get around this problem by using
-[`BigInt`](https://pursuit.purescript.org/packages/purescript-bigints/3.1.0/docs/Data.BigInt#t:BigInt).
+`Rational` is just a newtype over `Ratio BigInt` and you might want to use
+`Ratio` with other than `BigInt`. The type you choose must however be an `EuclideanRing`.
 
 ```
 > import Data.Ratio ((%), reduce)

bower.json

@@ -1,18 +1,13 @@
 {
   "private": true,
   "scripts": {
-    "postinstall": "bower install",
-    "build": "pulp build",
-    "test": "pulp test",
+    "build": "spago build",
     "spago-build": "spago build",
+    "test": "spago -x ./test.dhall test",
     "spago-test": "spago -x ./test.dhall test"
   },
   "devDependencies": {
-    "big-integer": "^1.6.51",
-    "bower": "^1.8.14",
-    "pulp": "^16.0.1",
-    "purescript": "^0.15.2",
-    "purs-tidy": "^0.9.2",
+    "purescript": "^0.15.8",
     "spago": "^0.20.9"
   }
 }

package.json

@@ -1,5 +1,5 @@
 let upstream =
-      https://github.com/purescript/package-sets/releases/download/psc-0.15.2-20220706/packages.dhall
-        sha256:7a24ebdbacb2bfa27b2fc6ce3da96f048093d64e54369965a2a7b5d9892b6031
+      https://github.com/purescript/package-sets/releases/download/psc-0.15.8-20230503/packages.dhall
+        sha256:b0ca02f2efb206465b499ee847f174212be0c8c2e031044b7bd192d5294f22cb
 
 in  upstream

packages.dhall

@@ -1,5 +1,5 @@
 { name = "rationals"
-, dependencies = [ "integers", "prelude" ]
+, dependencies = [ "integers", "js-bigints", "prelude" ]
 , license = "MIT"
 , repository = "https://github.com/purescript-contrib/purescript-rationals.git"
 , packages = ./packages.dhall

spago.dhall

@@ -1,19 +1,60 @@
 module Data.Rational
   ( Rational
+  , (%)
   , toNumber
   , fromInt
-  , module Data.Ratio
+  , fromBigInt
+  , numerator
+  , denominator
+  , class ToRational
+  , toRational
   ) where
 
 import Prelude
 
 import Data.Int as Int
 import Data.Ratio (Ratio, denominator, numerator, (%))
+import Data.Ratio as Ratio
+import JS.BigInt (BigInt)
+import JS.BigInt as BigInt
 
-type Rational = Ratio Int
+newtype Rational = Rational (Ratio.Ratio BigInt)
+
+derive newtype instance Eq Rational
+derive newtype instance Ord Rational
+derive newtype instance Show Rational
+derive newtype instance Semiring Rational
+derive newtype instance Ring Rational
+derive newtype instance CommutativeRing Rational
+derive newtype instance EuclideanRing Rational
+derive newtype instance DivisionRing Rational
 
 toNumber :: Rational -> Number
-toNumber x = Int.toNumber (numerator x) / Int.toNumber (denominator x)
+toNumber (Rational x) = BigInt.toNumber (Ratio.numerator x) / BigInt.toNumber (Ratio.denominator x)
 
 fromInt :: Int -> Rational
-fromInt i = i % 1
+fromInt i = Rational $ Ratio.reduce (BigInt.fromInt i) (BigInt.fromInt 1)
+
+fromBigInt :: BigInt -> Rational
+fromBigInt i = Rational $ Ratio.reduce i (BigInt.fromInt 1)
+
+numerator :: Rational -> BigInt
+numerator (Rational x) = Ratio.numerator x
+
+denominator :: Rational -> BigInt
+denominator (Rational x) = Ratio.denominator x
+
+class
+  ToRational a
+  where
+  toRational :: a -> a -> Rational
+
+instance ToRational Int
+  where
+  toRational a b = Rational $ Ratio.reduce (BigInt.fromInt a) (BigInt.fromInt b)
+
+instance ToRational BigInt
+  where
+  toRational a b = Rational $ Ratio.reduce a b
+
+infixl 7 toRational as %

src/Data/Rational.purs

@@ -2,6 +2,6 @@ let conf = ./spago.dhall
 
 in conf // {
   sources = conf.sources # [ "test/**/*.purs" ],
-  dependencies = conf.dependencies # [  "bigints", "console", "effect", "test-unit", "quickcheck", "quickcheck-laws"  ]
+  dependencies = conf.dependencies # [  "console", "effect", "integers", "quickcheck", "quickcheck-laws"  ]
 }
 

test.dhall

@@ -2,10 +2,10 @@ module Test.Main where
 
 import Prelude
 
-import Data.BigInt (BigInt, fromInt)
-import Data.Ratio (Ratio, (%))
+import Data.Rational (Rational, (%))
 import Effect (Effect)
 import Effect.Console (log)
+import JS.BigInt (BigInt, fromInt)
 import Test.QuickCheck (Result, quickCheck', (===))
 import Test.QuickCheck.Arbitrary (class Arbitrary, arbitrary)
 import Test.QuickCheck.Gen (Gen, suchThat)
@@ -14,7 +14,7 @@ import Test.QuickCheck.Laws.Data as Data
 import Test.QuickCheck.Laws.Data.Field (checkField) as DataField
 import Type.Proxy (Proxy(..))
 
-newtype TestRational = TestRational (Ratio BigInt)
+newtype TestRational = TestRational Rational
 
 derive newtype instance commutativeRingTestRational :: CommutativeRing TestRational
 derive newtype instance eqTestRational :: Eq TestRational
@@ -41,7 +41,7 @@ instance arbitraryTestRational :: Arbitrary TestRational where
 testRational :: Proxy TestRational
 testRational = Proxy
 
-newtype TestRatNonZero = TestRatNonZero (Ratio BigInt)
+newtype TestRatNonZero = TestRatNonZero Rational
 
 derive newtype instance eqTestRatNonZero :: Eq TestRatNonZero
 derive newtype instance semiringTestRatNonZero :: Semiring TestRatNonZero