Interval types updated

Research: This page describes research about Eiffel, not the actual language specification.

Introduction

This is a simplification of Read-write types where we use the syntax proposed in Interval types with a special meaning of the interval when it is the type of an actual generic parameter used in arguments or return type.

Example

When you have the following:

a: LIST [A .. B]
a.extend (x)     -- (1)
y := a.item   -- (2)

The rules, supposing that we have `extend (g: G)' and `item: G', are that:

• (1) is valid if and only if x is any type in the interval B .. NONE.
• (2) is valid if and only if y is any type in the interval ANY .. A.