Tests and some refinements

Author: odersky

library/src/scala/util/FromDigits.scala

@@ -23,9 +23,9 @@ object FromDigits {
 
   abstract class FromDigitsException(msg: String) extends NumberFormatException(msg)
 
-  class NumberTooLarge extends FromDigitsException("number too large")
-  class NumberTooSmall extends FromDigitsException("number too small")
-  class MalformedNumber extends FromDigitsException("malformed number literal")
+  class NumberTooLarge(msg: String = "number too large") extends FromDigitsException(msg)
+  class NumberTooSmall(msg: String = "number too small") extends FromDigitsException(msg)
+  class MalformedNumber(msg: String = "malformed number literal") extends FromDigitsException(msg)
 
   /** Convert digits and radix to integer value (either int or Long)
    *  This is tricky because of the max negative value.
@@ -66,7 +66,7 @@ object FromDigits {
    *                           Legal strings consist only of digits conforming to radix,
    *                           possibly preceded by a "-" sign.
    */
-  def intFromDigits(digits: String, radix: Int): Int =
+  def intFromDigits(digits: String, radix: Int = 10): Int =
     integerFromDigits(digits, radix, Int.MaxValue).toInt
 
   /** Convert digit string to Long number
@@ -77,7 +77,7 @@ object FromDigits {
    *                           Legal strings consist only of digits conforming to radix,
    *                           possibly preceded by a "-" sign.
    */
-  def longFromDigits(digits: String, radix: Int): Long =
+  def longFromDigits(digits: String, radix: Int = 10): Long =
     integerFromDigits(digits, radix, Long.MaxValue)
 
   @sharable private val zeroFloat = raw"-?[0.]+(?:[eE][+-]?[0-9]+)?[fFdD]?".r

tests/neg/GenericNumLits/Even_1.scala

@@ -0,0 +1,37 @@
+import scala.util.FromDigits
+import scala.quoted._
+import scala.quoted.matching._
+
+case class Even(n: Int)
+object Even {
+
+  private def evenFromDigits(digits: String): Even = {
+    val intValue = FromDigits.intFromDigits(digits)
+    if (intValue % 2 == 0) Even(intValue)
+    else throw FromDigits.MalformedNumber(s"$digits is odd")
+  }
+
+  private def evenFromDigitsImpl(digits: Expr[String]) given (ctx: QuoteContext): Expr[Even] = digits match {
+    case Const(ds) =>
+      val ev =
+        try evenFromDigits(ds)
+        catch {
+          case ex: FromDigits.FromDigitsException =>
+            ctx.error(ex.getMessage)
+            Even(0)
+        }
+      '{Even(${ev.n.toExpr})}
+    case _ =>
+      '{evenFromDigits($digits)}
+  }
+
+  class EvenFromDigits extends FromDigits[Even] {
+    def fromDigits(digits: String) = evenFromDigits(digits)
+  }
+
+  given as EvenFromDigits {
+    override inline def fromDigits(digits: String) = ${
+      evenFromDigitsImpl('digits)
+    }
+  }
+}

tests/neg/GenericNumLits/Test_2.scala

@@ -0,0 +1,5 @@
+object Test extends App {
+
+  val e1: Even = 1234
+  val e2: Even = 123  // error: 123 is odd
+}

tests/neg/GenericNumLits/Test_3.scala

@@ -0,0 +1,3 @@
+object Test extends App {
+  val e3: Even = 123456789101111 // error: number too large
+}

tests/run/genericNumLits.check

@@ -0,0 +1,5 @@
+13232202002020202020202
+-50390822187678765893036
+132322020020.223
+Even(1234)
+malformed

tests/run/genericNumLits.scala

@@ -0,0 +1,30 @@
+import scala.util.FromDigits
+object Test extends App {
+
+  val x: BigInt = 13232202002020202020202
+  val y: BigInt = -0xaabb12345ACF12345AC
+  val z: BigDecimal = 132322020020.223
+
+  case class Even(n: Int)
+
+  given as FromDigits[Even] {
+    def fromDigits(digits: String): Even = {
+      val intValue = digits.toInt
+      if (intValue % 2 == 0) Even(intValue)
+      else throw FromDigits.MalformedNumber()
+    }
+  }
+
+  val e: Even = 1234
+
+  println(x)
+  println(y)
+  println(z)
+  println(e)
+
+  try println(123: Even)
+  catch {
+    case ex: FromDigits.MalformedNumber => println("malformed")
+  }
+
+}