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From: ark@alice.UucP (Andrew Koenig)
Newsgroups: net.lang.c
Subject: Re: What should be added to C
Message-ID: <5498@alice.uUCp>
Date: Tue, 20-May-86 12:18:09 EDT
Article-I.D.: alice.5498
Posted: Tue May 20 12:18:09 1986
Date-Received: Fri, 23-May-86 06:24:48 EDT
References: <1462@mmintl.UUCP>
Organization: Bell Labs, Murray Hill
Lines: 61

Frank Adams says:

> As has been noted, one should use restraint in adding new features to a
> language.  What follows is a list of the features I would support adding to
> the *next* version of C (after the current standard is complete).

OK, let's see his examples of "restraint:"

> o Min and max operators.  These would get used all over the place.  These
> should be usable to the left of the assignment operator, as most but not all
> C operators are.

What would it mean to use these on the left of an assignment,
and why would you want to use it?

> o An andif clause for if statements.

What does it do and how would you use it?

> o The ability to define multi-line pre-processor macros, using #begdef and
> #enddef statements.  #if and other conditionals in the body of the
> definition would be evaluated when the macro was not interpreted, not when
> it is encountered.

Why would you want to use it?

> o A typeof operator, similar to sizeof.

What would its value be?  Why would you want to use it?

> o := as a synonym for =.  Compilers could have an option to permit := only.

Why bother?

> o Permit a continue statement in switch, meaning that the next label should
> be fallen through to.  Compilers and/or lint could produce when a program
> falls through without a continue statement.

A continue statement is already legal in a switch, as long as that
switch is enclosed in a for or while.  It means go on to the next
iteration of the enclosing loop.  Are you proposing to change this?

> o Any sort of multi-level break statement.  There is no syntacticly clean
> way of adding this to C.

C already has a multi-level break statement.  It's spelled "goto."
Putting a goto in a costume doesn't disguise it.

> o Elimination of the eight-character truncation of internal variable names
> done by some compilers.  (This may be in the current spec; I haven't read
> that document.)  The entire length of a variable name should be significant.

Most compilers do this already.


The trouble with adding new features to C is that there is a very
strong incentive not to use them.  After all, any program that
uses some new feature is only going to run on machines that support
that feature.  I don't think I'm going to be using only one compiler
for the rest of my life and would like to avoid changing my code
every time the environment hiccups.