Question

如何定义生成器以生成给定fields的{{1}}的随机数据。以下是脚手架代码。我需要一个表达式的帮助来替换Block。此表达式应生成???，但应使用已定义的Seq[Field]函数生成Field。

genField

ADT

def blockGen(b: Block): Gen[Block] = for {
    id <- b.blockId //Use the same blockId as b
    fields <- ??? //Get the type from each field and call genField
} yield Block(id, fields)

发电机

trait Data {}

trait Field extends Data {
  val name: String
  val value: String
}

case class StringField(name: String, value: String) extends Field
case class NumberField(name: String, value: String) extends Field
case class Block(blockId: Field, fields: Seq[Field]) extends Data

示例块：myBlock

def fieldGen(fieldType: Field): Gen[Field] = {
  for {
    f <-
    fieldType match {
      case _: NumberField => numGen
      case _: StringField => strGen
    }
  } yield f
}

val strGen: Gen[StringField] = for {
  name <- Gen.identifier
  value <- Gen.alphaStr
} yield StringField(name, value)

val numGen: Gen[NumberField] = for {
  name <- Gen.identifier
  value <- Gen.numStr
} yield NumberField(name, value)

Answer 1

我相信您正在寻找的是private let cellId = "cellId" class InfoViewShow: NSObject, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout { private let cellHeight:CGFloat = 80 var collectionView: UICollectionView? let layout = UICollectionViewFlowLayout() override init() { super.init() setupCollectionview() collectionView?.registerClass(InfoCell.self, forCellWithReuseIdentifier: cellId) } private func setupCollectionview() { if let view = UIApplication.sharedApplication().keyWindow { //let y = (view.frame.width * 10 / 16) + 34 + 26 collectionView = UICollectionView(frame: .zero , collectionViewLayout: layout) collectionView?.backgroundColor = UIColor.redColor() collectionView?.delegate = self collectionView?.dataSource = self collectionView?.frame = CGRectMake(0, 0, view.frame.width, view.frame.height) // y to y } } func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int { return 3 } func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell { let cell = collectionView.dequeueReusableCellWithReuseIdentifier(cellId, forIndexPath: indexPath) cell.backgroundColor = UIColor.blackColor() return cell } func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize { return CGSizeMake(collectionView.frame.width, cellHeight) } func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAtIndex section: Int) -> UIEdgeInsets { return UIEdgeInsetsMake(5, 5, 5, 5); //top,left,bottom,right } }。

此外，Gen.sequence并非需要来自生成器，因为您所做的只是直接使用特定值。

id

顺便说一下，def blockGen(b: Block): Gen[Block] = for { fields <- Gen.sequence[Seq[Field], Field](b.fields.map(fieldGen)) } yield Block(b.blockId, fields)与Future.sequence和sequence in Haskell非常相似。

根据另一个Gen定义ScalaCheck生成器

1 个答案: