Occurrences

The SCI.Occurrences children packages provide generic packages to compute occurrence of items.

Array based items

To find occurence of strings, instantiate with:

 package String_Occurrence is
    new SCI.Occurrences.Arrays (Element_Type => Character,
                                Index_Type   => Positive,
                                Array_Type   => String,
                                Occurrence_Type => Natural);

Finite Ordered Sets

The SCI.Occurrences.Finites package provides a ordered set where each element added is associated with an Occurrence_Type. A simple occurrence of words can be created with:

 package Word_Occurrences is
    new SCI.Occurrences.Finites
       (Element_Type => Ada.Strings.Unbounded.Unbounded_String,
        Occurrence_Type => Natural);

When items are added to the set, the Occurrence_Type values are merged with existing values. This is done by the generic Add procedure which must be instantiated with a + function that implements such merge.

 procedure Add is new Word_Occurrences.Add;

Operations of the package are used in several steps. In a first step, the items are collected and added to the set by using the Add procedure. Once all items are added, you will use:

• the Get function can be used to retrieve the occurence value associated with an item.
• the List procedure to extract a list of items and sort them according to a comparison function that you provide for the instantiation of the List procedure.
• the Sum and Longest procedures are helper functions that operate on the result produced by the List procedure.