List of Classes Comparer example

begin_definitions

const

var
  FruitList   : list (FruitClass)
  Fruit_1     : FruitClass
  Fruit_2     : FruitClass
  Fruit_3     : FruitClass
  SearchFruit : FruitClass
  ResultFruit : FruitClass
  FruitIndex  : numeric 1

type
  // Define the fruit class locally with the 'Implements IComparer' keywords
  FruitClass : class implements IComparer

    public
      ProductCode : numeric 3
      FruitType   : alpha 20

  end_class

booleans

end_definitions


public routine FruitClass.Compare (A : FruitClass, B : FruitClass) : integer

begin_routine

  // Compare and order the fruits alphabetically by type.
  if A.FruitType < B.FruitType
    result := -1
  elseif A.FruitType > B.FruitType
    result := 1
  else
    result := 0
  endif

end_routine


routine MAIN

begin_routine

  // Create 3 FruitClass instances, fill them with data and add them to FruitList.
  FillFruitListClasses ()

  // Sort the list according to the FruitClass compare routine.
  FruitList.Sort()

  // Create an instance with a type of fruit to search inside the fruit list.
  SearchFruit          := FruitClass.create ()
  SearchFruit.FruitType := 'Apple'

  // Search the list for an Apple fruit type.
  FruitIndex           := FruitList.IndexOf(SearchFruit)

  // Process the result of the search.
  if FruitIndex <> 0
    ResultFruit := FruitList[FruitIndex]
    sme('Searched Fruit code: ', ResultFruit.ProductCode)
  else
    sme('Fruit not found')
    exit all
  endif

  // Search the list for a second apple.
  FruitIndex := FruitList.IndexOf(SearchFruit, FruitIndex)

  if FruitIndex <> 0
    ResultFruit := FruitList[FruitIndex]
    sme('Searched Fruit second code: ', ResultFruit.ProductCode)
  else
    sme('Fruit not found second time around')
  endif

end_routine


routine FillFruitListClasses

begin_routine

  Fruit_1             := FruitClass.create ()
  Fruit_1.ProductCode := 055
  Fruit_1.FruitType   := 'Banana'
  FruitList.add (Fruit_1)

  Fruit_2             := FruitClass.create ()
  Fruit_2.ProductCode := 275
  Fruit_2.FruitType   := 'Apple'
  FruitList.add (Fruit_2)

  Fruit_3             := FruitClass.create ()
  Fruit_3.ProductCode := 867
  Fruit_3.FruitType   := 'Apple'
  FruitList.add (Fruit_3)

end_routine