[WIP] Basic implementation of JNumber conversions

README.md

@@ -91,6 +91,28 @@ in an undefined manner.
 Do note that according to the JSON spec, whether to order keys for a `JObject` is not specified. Also note that `Map` 
 disregards ordering for equality, however `Array`/`js.Array` equality takes ordering into account.
 
+## Number conversions
+ScalaJSON `JNumber` provides conversions to various number types with the following conventions
+
+* `toInt`: Safe conversion to `Int` which accounts for values such as `1.0` and `100.00e-2` (which both evaluate to `1`).
+Also safely detects over/underflow.
+* `toLong`: Safe conversion to `Long` which accounts for values such as `1.0` and `100.00e-2` (which both evaluate to `1`).
+Also  safely detects over/underflow.
+* `toDouble`: Converts to a `Double` assuming the same semantics of `Double` (i.e. precision loss is expected).
+* `toFloat`: Converts to a `Float` assuming the same semantics of `Float` (i.e. precision loss is expected).
+* `toBigInt`: Converts to a `BigInt` which accounts for values such as `1.0` and `100.00e-2` (which evaluates to `1`).
+Can construct a `BigInt`for as much as memory as the system has (if your system runs out of memory this is considered
+undefined behaviour).
+* `toBigDecimal`: Converts to a `BigDecimal` with all of the caveats of `BigDecimal` construction. The `BigDecimal` is
+constructed with `MathContext.UNLIMITED` precision.
+
+With the `.toFloat` and `.toDouble` methods, if you don't want any loss in precision, its advisable to convert to
+`BigDecimal` first and then work from there, i.e. when working with `Decimal`/`Float`, its implied that you will
+have loss of precision.
+
+Remember that in all cases if these methods are not applicable, you can always use the `.value` field to get the
+original string representation of the number.
+
 ## Scala.js
 ScalaJSON also provides support for [Scala.js](https://github.com/scala-js/scala-js).
 The usage of Scala.js mirrors the usage of Scala on the JVM however Scala.js also implements
@@ -103,6 +125,10 @@ underlying number (numbers in Javascript are represented as double precision flo
 You can use the `.value` method on a `scalajson.ast.JNumber`/`scalajson.ast.unsafe.JNumber` to
 get the raw string value as a solution to this problem.
 
+Further, `toFloat` on `JNumber` (see [Number Conversions](#number-conversions) ) can have different semantics on Scala.js, depending on whether you have
+strict-floats enabled in your application. Please see the [Scala.js semantics page](https://www.scala-js.org/doc/semantics.html)
+for more information.
+
 ## jNumberRegex
 `scalajson.JNumber` uses `jNumberRegex` to validate whether a number is a valid
 JSON number. One can use `jNumberRegex` explicitly if you want to use the validation that

benchmark/jvm/src/test/scala/benchmark/Constants.scala

@@ -0,0 +1,5 @@
+package benchmark
+
+object Constants {
+  @inline def innerLoopConstant: Int = 10000
+}

benchmark/jvm/src/test/scala/benchmark/Generators.scala

@@ -25,8 +25,9 @@ object Generators {
   def jNumber: Gen[ast.JNumber] =
     for {
       size <- Gen.range("seed")(300000, 1500000, 300000)
+      size2 <- Gen.range("seed")(300000, 1500000, 300000)
     } yield {
-      ast.JNumber(size)
+      ast.JNumber.fromString(s"$size.$size2").get
     }
 
   def jArray: Gen[ast.JArray] =

benchmark/jvm/src/test/scala/benchmark/JNumber.scala

@@ -7,7 +7,56 @@ object JNumber extends Bench.ForkedTime {
   performance of "JNumber" in {
     measure method "toFast" in {
       using(Generators.jNumber) in { jNumber =>
-        jNumber.toUnsafe
+        var i = 0
+        while (i < Constants.innerLoopConstant) {
+          jNumber.toUnsafe
+          i += 1
+        }
+      }
+    }
+    measure method "toInt" in {
+      using(Generators.jNumber) in { jNumber =>
+        var i = 0
+        while (i < Constants.innerLoopConstant) {
+          jNumber.toInt
+          i += 1
+        }
+      }
+    }
+    measure method "toLong" in {
+      using(Generators.jNumber) in { jNumber =>
+        var i = 0
+        while (i < Constants.innerLoopConstant) {
+          jNumber.toLong
+          i += 1
+        }
+      }
+    }
+    measure method "toBigInt" in {
+      using(Generators.jNumber) in { jNumber =>
+        var i = 0
+        while (i < Constants.innerLoopConstant) {
+          jNumber.toBigInt
+          i += 1
+        }
+      }
+    }
+    measure method "toBigDecimal" in {
+      using(Generators.jNumber) in { jNumber =>
+        var i = 0
+        while (i < Constants.innerLoopConstant) {
+          jNumber.toBigDecimal
+          i += 1
+        }
+      }
+    }
+    measure method "toDouble" in {
+      using(Generators.jNumber) in { jNumber =>
+        var i = 0
+        while (i < Constants.innerLoopConstant) {
+          jNumber.toDouble
+          i += 1
+        }
       }
     }
   }

benchmark/jvm/src/test/scala/benchmark/unsafe/JNumber.scala

@@ -1,5 +1,6 @@
 package benchmark.unsafe
 
+import benchmark.Constants
 import org.scalameter.Bench
 
 object JNumber extends Bench.ForkedTime {
@@ -10,5 +11,50 @@ object JNumber extends Bench.ForkedTime {
         jNumber.toStandard
       }
     }
+    measure method "toInt" in {
+      using(Generators.jNumber) in { jNumber =>
+        var i = 0
+        while (i < Constants.innerLoopConstant) {
+          jNumber.toInt
+          i += 1
+        }
+      }
+    }
+    measure method "toLong" in {
+      using(Generators.jNumber) in { jNumber =>
+        var i = 0
+        while (i < Constants.innerLoopConstant) {
+          jNumber.toLong
+          i += 1
+        }
+      }
+    }
+    measure method "toBigInt" in {
+      using(Generators.jNumber) in { jNumber =>
+        var i = 0
+        while (i < Constants.innerLoopConstant) {
+          jNumber.toBigInt
+          i += 1
+        }
+      }
+    }
+    measure method "toBigDecimal" in {
+      using(Generators.jNumber) in { jNumber =>
+        var i = 0
+        while (i < Constants.innerLoopConstant) {
+          jNumber.toBigDecimal
+          i += 1
+        }
+      }
+    }
+    measure method "toDouble" in {
+      using(Generators.jNumber) in { jNumber =>
+        var i = 0
+        while (i < Constants.innerLoopConstant) {
+          jNumber.toDouble
+          i += 1
+        }
+      }
+    }
   }
 }

js/src/main/scala-2.10/scalajson.ast/JValue.scala

@@ -98,14 +98,6 @@ object JNumber {
 // Due to a restriction in Scala 2.10, we cant override/replace the default apply method
 // generated by the compiler even when the constructor itself is marked private
 final class JNumber private[ast] (val value: String) extends JValue {
-
-  /**
-    * Javascript specification for numbers specify a [[scala.Double]], so this is the default export method to `Javascript`
-    *
-    * @param value
-    */
-  def this(value: Double) = this(value.toString)
-
   override def toUnsafe: unsafe.JValue = unsafe.JNumber(value)
 
   override def toJsAny: js.Any = value.toDouble match {
@@ -146,6 +138,18 @@ final class JNumber private[ast] (val value: String) extends JValue {
       case jNumberRegex(_ *) => new JNumber(value)
       case _ => throw new NumberFormatException(value)
     }
+
+  def toInt: Option[Int] = scalajson.ast.toInt(value)
+
+  def toBigInt: Option[BigInt] = scalajson.ast.toBigInt(value)
+
+  def toLong: Option[Long] = scalajson.ast.toLong(value)
+
+  def toDouble: Double = scalajson.ast.toDouble(value)
+
+  def toFloat: Float = scalajson.ast.toFloat(value)
+
+  def toBigDecimal: Option[BigDecimal] = scalajson.ast.toBigDecimal(value)
 }
 
 /** Represents a JSON Boolean value, which can either be a

js/src/main/scala-2.10/scalajson.ast/unsafe/JValue.scala

@@ -87,19 +87,27 @@ object JNumber {
 final case class JNumber(value: String) extends JValue {
   override def toStandard: ast.JValue =
     value match {
-      case jNumberRegex(_ *) => new ast.JNumber(value)
-      case _ => throw new NumberFormatException(value)
+      case jNumberRegex(_*) => new ast.JNumber(value)
+      case _                => throw new NumberFormatException(value)
     }
 
-  def this(value: Double) = {
-    this(value.toString)
-  }
-
   override def toJsAny: js.Any = value.toDouble match {
-    case n if n.isNaN => null
+    case n if n.isNaN      => null
     case n if n.isInfinity => null
-    case n => n
+    case n                 => n
   }
+
+  def toInt: Option[Int] = scalajson.ast.toInt(value)
+
+  def toBigInt: Option[BigInt] = scalajson.ast.toBigInt(value)
+
+  def toLong: Option[Long] = scalajson.ast.toLong(value)
+
+  def toDouble: Double = scalajson.ast.toDouble(value)
+
+  def toFloat: Float = scalajson.ast.toFloat(value)
+
+  def toBigDecimal: Option[BigDecimal] = scalajson.ast.toBigDecimal(value)
 }
 
 /** Represents a JSON Boolean value, which can either be a
@@ -229,11 +237,11 @@ final case class JObject(value: js.Array[JField] = js.Array()) extends JValue {
                               else {
                                 result = 31 * result + elem.field.##
                                 elem.value match {
-                                  case unsafe.JNull => unsafe.JNull.##
-                                  case unsafe.JString(s) => s.##
-                                  case unsafe.JBoolean(b) => b.##
-                                  case unsafe.JNumber(i) => i.##
-                                  case unsafe.JArray(a) => a.##
+                                  case unsafe.JNull        => unsafe.JNull.##
+                                  case unsafe.JString(s)   => s.##
+                                  case unsafe.JBoolean(b)  => b.##
+                                  case unsafe.JNumber(i)   => i.##
+                                  case unsafe.JArray(a)    => a.##
                                   case unsafe.JObject(obj) => obj.##
                                 }
                               })
@@ -301,11 +309,11 @@ final case class JArray(value: js.Array[JValue] = js.Array()) extends JValue {
       result = 31 * result + (if (elem == null) 0
                               else {
                                 elem match {
-                                  case unsafe.JNull => unsafe.JNull.##
-                                  case unsafe.JString(s) => s.##
-                                  case unsafe.JBoolean(b) => b.##
-                                  case unsafe.JNumber(i) => i.##
-                                  case unsafe.JArray(a) => a.##
+                                  case unsafe.JNull        => unsafe.JNull.##
+                                  case unsafe.JString(s)   => s.##
+                                  case unsafe.JBoolean(b)  => b.##
+                                  case unsafe.JNumber(i)   => i.##
+                                  case unsafe.JArray(a)    => a.##
                                   case unsafe.JObject(obj) => obj.##
                                 }
                               })

js/src/main/scala/scalajson/ast/JValue.scala

@@ -98,13 +98,6 @@ object JNumber {
   */
 final case class JNumber private[ast] (value: String) extends JValue {
 
-  /**
-    * Javascript specification for numbers specify a [[scala.Double]], so this is the default export method to `Javascript`
-    *
-    * @param value
-    */
-  def this(value: Double) = this(value.toString)
-
   override def toUnsafe: unsafe.JValue = unsafe.JNumber(value)
 
   override def toJsAny: js.Any = value.toDouble match {
@@ -128,6 +121,18 @@ final case class JNumber private[ast] (value: String) extends JValue {
       case jNumberRegex(_*) => new JNumber(value)
       case _                => throw new NumberFormatException(value)
     }
+
+  def toInt: Option[Int] = scalajson.ast.toInt(value)
+
+  def toBigInt: Option[BigInt] = scalajson.ast.toBigInt(value)
+
+  def toLong: Option[Long] = scalajson.ast.toLong(value)
+
+  def toDouble: Double = scalajson.ast.toDouble(value)
+
+  def toFloat: Float = scalajson.ast.toFloat(value)
+
+  def toBigDecimal: Option[BigDecimal] = scalajson.ast.toBigDecimal(value)
 }
 
 /** Represents a JSON Boolean value, which can either be a

js/src/main/scala/scalajson/ast/unsafe/JValue.scala

@@ -89,15 +89,23 @@ final case class JNumber(value: String) extends JValue {
       case _                => throw new NumberFormatException(value)
     }
 
-  def this(value: Double) = {
-    this(value.toString)
-  }
-
   override def toJsAny: js.Any = value.toDouble match {
     case n if n.isNaN      => null
     case n if n.isInfinity => null
     case n                 => n
   }
+
+  def toInt: Option[Int] = scalajson.ast.toInt(value)
+
+  def toBigInt: Option[BigInt] = scalajson.ast.toBigInt(value)
+
+  def toLong: Option[Long] = scalajson.ast.toLong(value)
+
+  def toDouble: Double = scalajson.ast.toDouble(value)
+
+  def toFloat: Float = scalajson.ast.toFloat(value)
+
+  def toBigDecimal: Option[BigDecimal] = scalajson.ast.toBigDecimal(value)
 }
 
 /** Represents a JSON Boolean value, which can either be a

jvm/src/main/scala-2.10/scalajson.ast/JValue.scala

@@ -125,6 +125,18 @@ final class JNumber private[ast] (val value: String) extends JValue {
       case jNumberRegex(_ *) => new JNumber(value)
       case _ => throw new NumberFormatException(value)
     }
+
+  def toInt: Option[Int] = scalajson.ast.toInt(value)
+
+  def toBigInt: Option[BigInt] = scalajson.ast.toBigInt(value)
+
+  def toLong: Option[Long] = scalajson.ast.toLong(value)
+
+  def toDouble: Double = scalajson.ast.toDouble(value)
+
+  def toFloat: Float = scalajson.ast.toFloat(value)
+
+  def toBigDecimal: Option[BigDecimal] = scalajson.ast.toBigDecimal(value)
 }
 
 /** Represents a JSON Boolean value, which can either be a

jvm/src/main/scala-2.10/scalajson.ast/unsafe/JValue.scala

@@ -76,6 +76,18 @@ final case class JNumber(value: String) extends JValue {
       case jNumberRegex(_ *) => new ast.JNumber(value)
       case _ => throw new NumberFormatException(value)
     }
+
+  def toInt: Option[Int] = scalajson.ast.toInt(value)
+
+  def toBigInt: Option[BigInt] = scalajson.ast.toBigInt(value)
+
+  def toLong: Option[Long] = scalajson.ast.toLong(value)
+
+  def toDouble: Double = scalajson.ast.toDouble(value)
+
+  def toFloat: Float = scalajson.ast.toFloat(value)
+
+  def toBigDecimal: Option[BigDecimal] = scalajson.ast.toBigDecimal(value)
 }
 
 /** Represents a JSON Boolean value, which can either be a

jvm/src/main/scala/scalajson/ast/JValue.scala

@@ -106,6 +106,18 @@ final case class JNumber private[ast] (value: String) extends JValue {
       case jNumberRegex(_*) => new JNumber(value)
       case _                => throw new NumberFormatException(value)
     }
+
+  def toInt: Option[Int] = scalajson.ast.toInt(value)
+
+  def toBigInt: Option[BigInt] = scalajson.ast.toBigInt(value)
+
+  def toLong: Option[Long] = scalajson.ast.toLong(value)
+
+  def toDouble: Double = scalajson.ast.toDouble(value)
+
+  def toFloat: Float = scalajson.ast.toFloat(value)
+
+  def toBigDecimal: Option[BigDecimal] = scalajson.ast.toBigDecimal(value)
 }
 
 /** Represents a JSON Boolean value, which can either be a