Section Header
    + name := FAST_ARRAY2[E];
    - comment :="Resizable two dimensional array. \
\Unlike ARRAY2, the `lower1' bound and the `lower2' \
\bound are frozen to 0. Thus, one can expect better \
\performances.";
Section Inherit
    + parent_collection2:Expanded COLLECTION2[E];
Section Public
    + upper1:INTEGER;
    + count1:INTEGER;
    + upper2:INTEGER;
    + count2:INTEGER;
    + count:INTEGER;
Section FAST_ARRAY2
    + storage:NATIVE_ARRAY[E];
    + capacity :INTEGER;
        of `storage'.
Section Public
    - lower1:INTEGER :=
    - lower2:INTEGER :=
    - create (new_count1,new_count2:INTEGER) :SELF<-
        Create with new dimensions.
        All elements are set to the default value of type E.
    - make (new_count1,new_count2:INTEGER) <-
        Create or reset self with new dimensions.
        All elements are set to the default value of type E.
    - from_collection2 model:COLLECTION2[E] <-
        Uses the `model' to update self.
    - from_collection contents:COLLECTION[E] size (new_count1, new_count2:INTEGER) <-
        Reset all bounds using `new_count#i'.
        Copy all elements of `contents', line by line into Current.
    - from_model model:COLLECTION[COLLECTION[E]] <-
        The `model' is used to fill line by line the COLLECTION2.
        Assume all sub-collections of `model' have the number of items.
    - sub_collection2 (line_min,column_min:INTEGER) to (line_max,column_max:INTEGER) :SELF <-
Implementation of others feature from COLLECTION2:
    - item (line, column:INTEGER) :E <-
    - put element:E to (line, column:INTEGER) <-
    - force element:E to (line , column :INTEGER) <-
    - copy other:SELF <-
Writing.
    - set_all_with v:E <-
        All element are set with the value v.
    - all_default:BOOLEAN <-
    - slice (l1,up1:INTEGER) to (l2,up2:INTEGER) :SELF <-
        Create a new collection initialized with elements of
        range `low'..`up'. result has the same dynamic type
        as self collection.
    - set_slice (l1,up1:INTEGER) to (l2,up2:INTEGER) with element:E <-
        Set all the elements in the range [(l1,up1),(l2,up2)] of
        self with the element 'element'.
    - swap (line1, column1:INTEGER) with (line2, column2:INTEGER) <-
Looking and comparison:
    - occurrences elt:E :INTEGER <-
    - fast_occurrences elt:E :INTEGER <-
Resizing:
    - resize (new_count1,new_count2:INTEGER) <-
Looking and Searching:
    - has x:E :BOOLEAN <-
        Look for `x' using `equal' for comparison.
    - fast_has x:E :BOOLEAN <-
        Same as `has' but use `=' for comparison
Other features:
    - replace_all old_value:E with new_value:E <-
    - fast_replace_all old_value:E with new_value:E <-
    - transpose <-
        Transpose the self array
    - to_external:POINTER <-
        Gives C access to the internal `storage' (may be dangerous).
Invariant.
[ ...
-? { count1 = upper1 + 1 };
-? { count2 = upper2 + 1 };
-? { count = count1 * count2};
-? { capacity >= count };
];