Re: How to process contents of a list variable through a macro ?

On Tue, 20 Feb 2007 13:03:41 +0100, joswig@xxxxxxxxxxxxxxxxxxxxxxx <joswig@xxxxxxxxxxxxxxxxxxxxxxx> wrote:

On Feb 20, 12:34 pm, "John Thingstad" <john.things...@xxxxxxxxx>
wrote:
On Tue, 20 Feb 2007 09:16:48 +0100, jos...@xxxxxxxxxxxxxxxxxxxxxxx

<jos...@xxxxxxxxxxxxxxxxxxxxxxx> wrote:

> A DEFPARAMETER doesn't get executed at compile time.
> But the compiler executes the Macros during compile time.
> Even those that are defined in the file you compile.
> If a macro then references a variable that is in
> the same file...

A DEFPARAMETER does (!) get executed at compile time.
It is a DEFVAR declaration that dosn't.

That's wrong.

CLHS:

If a defvar or defparameter form appears as a top level form, the
compiler must recognize that the name has been proclaimed special.
However, it must neither evaluate the initial-value form nor assign
the dynamic variable named name at compile time.


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Hyperspec:

"defparameter unconditionally assigns the initial-value to the dynamic variable named name.
defvar, by contrast, assigns initial-value (if supplied) to the dynamic variable named name only
if name is not already bound."

So defvar values get assigned a value when they are first loaded and then remain the same.
defparameter values by contrast get assigned te initial value each time they are evalueated
/compiled.

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