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From: firth@sei.cmu.edu (Robert Firth)
Newsgroups: comp.lang.c
Subject: Re: learning C declaration syntax
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Date: Thu, 3-Sep-87 11:09:37 EDT
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Posted: Thu Sep  3 11:09:37 1987
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In article <223@xyzzy.UUCP> throopw@xyzzy.UUCP (Wayne A. Throop) writes:

[ is the syntax of C declarations confusing ]

>This is a widespread reaction to C declaration syntax, and in many ways
>I can see the point.  I thought it arbitrary and bizarre until I read
>the explanatory note in the K&R tutorial which states that declaration
>syntax mimics expression syntax.  But once one knows this about
>declarations, why is it still difficult?  After all, are assignments
>like
>
>        *a1[n] = 23;
>or
>        (*a2)[n] = 23;
>or
>        i = (*a3[n])();
>
>confusing?

Wayne, I find the syntax of both declaration and use very hard to read.
perhaps if I used only C I'd get used to it, but I don't.

There seem to me two main sources of confusion for other than C experts.
The first is a use of graphical symbols that is, by almost any standard,
highly eccentric.  That "*" is a good example.  Any naive person knows
that "*" is the ASCII symbol for "multiply".  To use it for indirection
is strange.  To use it for both indirection AND to mean "POINTER TO" in
a declaration is doubly strange.

The second cause of confusion is really trivial, but its ramifications
are enormous.  There are basically three composable structuring symbols
in C: "*" (POINTER TO), "[]" (ARRAY OF), and "()" (FUNCTION RETURNING).
One uses prefix syntax, the other two use postfix.  That is a disastrous
error in human engineering.  If all three were postfix, I believe C code
would be much easier to read.  To see what I mean, try reading some
Modula-2 code, where all the destructuring operations are postfix; it's
easy to see that

	x[i]^[j].k

simply means "take the i'th element of X, dereference, take the j'th element,
select the k component.

The combination of prefix and postfix syntax also of course creates
problems over strength of binding, and hence the need for all those
parentheses.  You know, to create a binding order problem for essentially
monadic operators seems pretty incompetent to me (but I'm biased, as
you perceive).