Doc: Please read the eiffel_rename.pdf

Abstract

We discovered a loophole in Eiffel's field renaming mechanism when applied to the diamond problem of multiple inheritance. To fix the loophole we propose to abandon the renaming's reference identity semantics; we introduce a concept called virtual field, and propose two methods: the first method is manual fix with help from enhanced programming rules, e.g. direct virtual field access is only allowed in accessor methods (among other rules); and the second method is automatic, we introduce rename dispatching based on the object's runtime view stack, hence providing an improved solution to multiple inheritance (esp. for unplanned MI).

Software: Please make sure you have the following Eiffel compilers installed on your system:

1. ISE EiffelStudio 22.12.10.6463 (released in 2022), https://account.eiffel.com/downloads
2. Gobo Eiffel compiler gec version 22.01.09.4 (released in 2022) https://sourceforge.net/projects/gobo-eiffel/files/gobo-eiffel/22.01/
3. GNU SmartEiffel version 1.1 (released in 2003), the source distribution is included here: SmartEiffel-1.1.tar.bz2

NOTE: for SmartEiffel 1.1, since it's an old version, it only works on 32-bit Linux. Otherwise, for 64-bit please use MacOS.

For our demo, we used Linux system.

Demo:

For Section 2: the Eiffel’s field renaming problem we found

$ git submodule update --init

$ cd  eiffel_bug

# test ISE EiffelStudio 22.12.10.6463 (released in 2022)
$ make ise
$ cat  ise.out   # to see the output

# test Gobo Eiffel compiler gec version 22.01.09.4 (released in 2022)
# make gobo
# cat  gobo.out  # to see the output

# test SmartEiffel version 1.1 (released in 2003)
$ cd se
$ make se
$ cat  se.out   # to see the output

For Section 3, manual fix with virtual field accessor

$ cd  eiffel_fix

# then repeat the same commands as above

For Section 4 and 5, to see our automatic fix:

First make sure you have Python and dmd (version v2.102.2, you MUST use this version) installed: https://downloads.dlang.org/releases/2.x/2.102.2/

Then:

$ cd yi
$ make

in the build process, you may see messages like:

ERROR! Autowrap could not wrap aggregate ...

these messages are safe to be ignored.