Re: [tlug] Bleeding pragmata

["Stephen J. Turnbull" <stephen@example.com>]

On 17/02/06, Tod McQuillin <devin@example.com> wrote:

    >>> The C99 standard allows variable declarations anywhere inside
    >>> a block, not just at the top.  This can be a useful technique
    >>> for limiting the scope of variables to just the section of
    >>> code where they are used.

Saves two characters: '{' and '}'.  Big whup.  ;-)  Of course,
according to your coding style you may need to add a bunch of extra
whitespace, but for me this is usually balanced by the readability
advantage of demarcating the scope of the declaration, and the fact
that there's an explicit end-of-scope indicator (which is often more
important to me than the beginning-of-scope indicator).

>>>>> "Edward" == Edward Middleton <edward@example.com> writes:

    Edward> Josh Glover wrote:

    >> Thanks for pointing this out.

    Edward> Well if you hadn't send the last email you might of got
    Edward> away with something along the lies of

    Edward> [1]It's a coding style issue. We put our variable
    Edward> declarations where people can _find_ them, not in random
    Edward> places in the code.

I'll second that.  XEmacs still compiles with GCC 2.4 (although that's
an accident, we only *want* to support 2.95 :-).  And there are vendor
compilers that don't support C99 yet, although they're getting quite
rare.

    Edward> Putting variables in the middle of code only improves
    Edward> readability when you have messy code.

IMO, there's an important exception.  It also allows you to initialize
at the point of declaration.  That can be a perceptible readability
improvement if your initialization depends on an intermediate result.

Granted, you might be even better off putting the block in a function
and letting the compiler inline it, but for inner loop code you might
not want to do that, especially if you need to support a lot of
compilers and don't know what their policies on inlining are (or know
that some compilers won't inline the code in question).  Or the block
might use a lot of variables that you'd have to pass as arguments, or
something.

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