Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!mcsun!sunic!enea!sommar
From: sommar@enea.se (Erland Sommarskog)
Newsgroups: comp.lang.eiffel
Subject: Re: Eiffel cleanup #1: The creation mechanism
Message-ID: <667@enea.se>
Date: 20 Jan 90 23:53:35 GMT
References: <226@eiffel.UUCP>
Organization: Enea Data AB, Sweden
Lines: 31

Bertrand Meyer (bertrand@eiffel.UUCP) writes:
>There is only one creation instruction. Its most general form is
>
>    x !D! f (...)
>
>where x is a read-write entity of some type C and D is a descendant of
>C; f must be a creation procedure of D. This creates an instance of
>D, applies the default initializations, calls f with the actual arguments
>given, and attaches the resulting object to x.

While I have nothing against the concept as such, rather the
opposite, I am not appealed of the syntax. I have the opinion
that artificial symbols should be avoided, particulary if they
are not commonly used elsewhere. If you don't know Eiffel and
looks at a piece of code and sees "x !!" it will take some time
until you understand what is going on. (It is possible that !!
is common in this meaning. It is new to me, however.)

Maybe I have had a too big exposure to Cobol, but I would propose

   create x as D using f(...)

with "as D" and "using f(...)" being optional as in Dr. Meyer's
article. This would require a new keyword "using" and that "create"
would remain being one. Whether "using" is a common identifier, I
don't know, but I wouldn't expect it to be.
  This not only has the advantage to allievate the readability, but
also it gives a better understanding of what you are doing.

-- 
Erland Sommarskog - ENEA Data, Stockholm - sommar@enea.se
Unix is a virus.