Creating implementation for idiom 303 : Array with non-default lower bound

Idiom

# 303 Array with non-default lower bound

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Declare an array a of integers with six elements, where the first index is 42 and consecutive elements have the indices 43, 44, 45, 46, 47.

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A : array (42 .. 47) of Integer;

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  integer, dimension(42:47) :: a

import java.util.ArrayList;

class A<T> extends ArrayList<T> {
    int i;
    A(int lowerBound) { i = lowerBound; }
    public void add(int i, T x) {
        super.add(i - this.i, x);
    }
    public T set(int i, T x) {
        return super.set(i - this.i, x);
    }
    public T get(int i) {
        return super.get(i - this.i);
    }
}

var
  a: array[42..47] of integer;

use feature 'say';

use Array::Base +42;

my @a = ('A'..'Z');

say $a[42]; # prints A
say $a[43]; # prints B

no Array::Base;  # restore indexing to base 0

import array

a = array.array("i", range(42,48))

class List(list):
    def __init__(self, offset, *args):
        super().__init__(*args)
        self.offset = offset
    def offset(method):
        def wrapped(self, index, *args):
            index -= self.offset
            return method(self, index, *args)
        return wrapped
    @offset
    def __setitem__(self, key, value):
        super().__setitem__(key, value)
    @offset
    def __getitem__(self, item):
        return super().__getitem__(item)
a = List(42, 'abcdef')

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