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author | Dmitry Petrashko <dmitry.petrashko@gmail.com> | 2015-05-12 18:30:53 +0200 |
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committer | Dmitry Petrashko <dmitry.petrashko@gmail.com> | 2015-05-12 18:30:53 +0200 |
commit | 89bacb9c25a58454ff1878e67f7ea07ffc8c269f (patch) | |
tree | 51f1ff6c66aebe1b6109b1cffcc2bb8e4cf760a3 /tests/pending/run/reify_fors_oldpatmat.scala | |
parent | a0fa33deafbea1bf53edc068c5ed9db5592822f9 (diff) | |
download | dotty-89bacb9c25a58454ff1878e67f7ea07ffc8c269f.tar.gz dotty-89bacb9c25a58454ff1878e67f7ea07ffc8c269f.tar.bz2 dotty-89bacb9c25a58454ff1878e67f7ea07ffc8c269f.zip |
Run tests as they were in scala.
Diffstat (limited to 'tests/pending/run/reify_fors_oldpatmat.scala')
-rw-r--r-- | tests/pending/run/reify_fors_oldpatmat.scala | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/tests/pending/run/reify_fors_oldpatmat.scala b/tests/pending/run/reify_fors_oldpatmat.scala new file mode 100644 index 000000000..6bee9538a --- /dev/null +++ b/tests/pending/run/reify_fors_oldpatmat.scala @@ -0,0 +1,101 @@ +import scala.reflect.runtime.universe._ +import scala.tools.reflect.Eval + +object Test extends App { + reify { + object Persons { + /** A list of persons. To create a list, we use Predef.List + * which takes a variable number of arguments and constructs + * a list out of them. + */ + val persons = List( + new Person("Bob", 17), + new Person("John", 40), + new Person("Richard", 68) + ) + + /** A Person class. 'val' constructor parameters become + * public members of the class. + */ + class Person(val name: String, val age: Int) + + /** Return an iterator over persons that are older than 20. + */ + def olderThan20(xs: Seq[Person]): Iterator[String] = + olderThan20(xs.iterator) + + /** Return an iterator over persons older than 20, given + * an iterator over persons. + */ + def olderThan20(xs: Iterator[Person]): Iterator[String] = { + + // The first expression is called a 'generator' and makes + // 'p' take values from 'xs'. The second expression is + // called a 'filter' and it is a boolean expression which + // selects only persons older than 20. There can be more than + // one generator and filter. The 'yield' expression is evaluated + // for each 'p' which satisfies the filters and used to assemble + // the resulting iterator + for (p <- xs if p.age > 20) yield p.name + } + } + + /** Some functions over lists of numbers which demonstrate + * the use of for comprehensions. + */ + object Numeric { + + /** Return the divisors of n. */ + def divisors(n: Int): List[Int] = + for (i <- List.range(1, n+1) if n % i == 0) yield i + + /** Is 'n' a prime number? */ + def isPrime(n: Int) = divisors(n).length == 2 + + /** Return pairs of numbers whose sum is prime. */ + def findNums(n: Int): Iterable[(Int, Int)] = { + + // a for comprehension using two generators + for (i <- 1 until n; + j <- 1 until (i-1); + if isPrime(i + j)) yield (i, j) + } + + /** Return the sum of the elements of 'xs'. */ + def sum(xs: List[Double]): Double = + xs.foldLeft(0.0) { (x, y) => x + y } + + /** Return the sum of pairwise product of the two lists. */ + def scalProd(xs: List[Double], ys: List[Double]) = + sum(for((x, y) <- xs zip ys) yield x * y); + + /** Remove duplicate elements in 'xs'. */ + def removeDuplicates[A](xs: List[A]): List[A] = + if (xs.isEmpty) + xs + else + xs.head :: removeDuplicates(for (x <- xs.tail if x != xs.head) yield x) + } + + // import all members of object 'persons' in the current scope + import Persons._ + + print("Persons over 20:") + olderThan20(persons) foreach { x => print(" " + x) } + println + + import Numeric._ + + println("divisors(34) = " + divisors(34)) + + print("findNums(15) =") + findNums(15) foreach { x => print(" " + x) } + println + + val xs = List(3.5, 5.0, 4.5) + println("average(" + xs + ") = " + sum(xs) / xs.length) + + val ys = List(2.0, 1.0, 3.0) + println("scalProd(" + xs + ", " + ys +") = " + scalProd(xs, ys)) + }.eval +}
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