collections

Introduction

COLLECTIONS is a library providing a set of types supporting collections in Fortran. The collection types within this library are object-oriented by design, and utilize Fortran's unlimited polymorphic variable functionallity allowing storage of any data type.

This library relies upon the FERROR library to provide a mechanism for communicating any runtime errors that may occur while using this library.

Example

One of the collection types this library provides is a generic, dynamically sizeable type referred to simply as list. A simple example illustrating basic usage of the list type is as follows.

program list_example
    use collections
    use iso_fortran_env
    implicit none
 
    ! Variables
    integer(int32), parameter :: n = 10
    integer(int32) :: i
    type(list) :: x
    class(*), pointer :: ptr
 
    ! Create a list
    do i = 1, n
        call x%push(2 * i)
    end do
 
    ! Print it out to the command line
    print '(A)', "***** Original List *****"
    do i = 1, n
        ptr => x%get(i)
 
        ! The list uses unlimited polymorphic types; therefore, we need to
        ! use the select type construct.
        select type (ptr)
        type is (integer(int32))
            print *, ptr
        end select
    end do
 
    ! Insert the integer value of 100 into the 5th slot in the list
    call x%insert(5, 100)
 
    ! Print it out again to illustrate the change
    print '(A)', new_line('a') // "***** After Insertion *****"
    do i = 1, x%count()
        ptr => x%get(i)
        select type (ptr)
        type is (integer(int32))
            print *, ptr
        end select
    end do

This program generates the following output.

***** Original List *****
           2
           4
           6
           8
          10
          12
          14
          16
          18
          20
 
***** After Insertion *****
           2
           4
           6
           8
         100
          10
          12
          14
          16
          18
          20