Although I largely agree, I think that line of thinking can be taken too far.
One reason I think that is because syntax helps develop conventions and make them obvious. If everything is an s-expr and you can do absolutely anything with macros anywhere, then two programmers might not really be able to communicate even if they are technically using the same language.
When several programmers develop on a mutual codebase, there is not one programming language where coding conventions are unnecessary. This is hardly an argument against Lisps. In fact the clojure code I read so far seems to adhere far more to conventions than code of almost any other programming language I have worked with so far.
Macros are pretty much like Classes, Gotos/Loops, Exceptions, Functions, etc in this respect, the communities have mostly agreed on conventions _when_ and _how_ to use them.
I think the argument that macros will make a codebase unreadable to other programmers is largely an exaggeration to turn a pro-Lisp argument against Lisp. Its a pattern I have heard a little too often:
"C++ is powerful" -> "C++ is too powerful"
"Macros let you express ..." -> "Macros can do just too much"
Now in my non-Lisp programming, I miss macros a lot. Especially those that are built into a lot of lisps and are quite "simple" additions. The Clojure threading macro for example, or `if-let` variable binding, or the awesome xml-templating languages that are realizable with macros. On the other hand, I have seen code that - for me as an outsider - came quite close to what you describe, just that it hardly was Lisp but PHP, Javascript, etc. Macros, like functions and classes are part of the vocabulary programmers build.
So next time when you criticize macros, talk about something that is worth debating, like the fact that they can be unsafe (hygiene), they are not intuitively writable like functions, they might make debugging harder, etc.
I wasn't criticizing macros; I claimed that they don't give you much guidance to any particular convention because you can do anything.
A language without conventions is incomplete, so you need to do something active to bring the conventions about. In other words, the designers of lisp leave conventions as an exercise for the reader and really offer no guidance from the language itself.
Clojure and racket are trying to address that, which is good. I've played around with them a bit, generally found them pleasant, and I hope they succeed (though I did not find anything that would compel me to actually use them for the kinds of things I work on).
It's interesting that you bring up C++. I wonder what your feelings are about people who prefer C over C++?
Regarding C and C++, I am slightly leaning towards C. While C++ offers some abstractions over C that are really nice to have, it often feels like an awkward chimera. I see C as a even-higher-level assembly language. c++ was a logical step but is kind of obsolete for non-realtime systems
Guidance in a language is a hard thing to do right. I think the only reasonable way of guidance is to make good coding practice simple, limiting guidance is often quite bad [1], because while in a lot of cases it makes things easier, there are those cases where you then have to work around the limitations and this is when you get those "bug ridden incomplete implementations" of that "liberal" language.
Which good guidances from which programming languages are you fond of?
[1] now that I think about it, I do like immutability in functional programming languages - a not-so-liberal thing..
I'm not sure there is a point worth debating. Hygiene is left to the programmer and the facilities exist to write "safe" macros (gensym). Debugging isn't terribly difficult with macro-expansion facilities. The only "problem" with them, if you can call it that, is that newbies like to over-use them once they learn them. However that problem goes away with time.
Macros in the hands of an intermediate-to-experienced programmer are powerful tools. They remove patterns from your code. They allow you to modify the compiler to efficiently run your program. And all sorts of good things.
People arguing that X "is too powerful" are saying that nobody needs a combine harvester when a team of farmers with scythes will do.
One reason I think that is because syntax helps develop conventions and make them obvious. If everything is an s-expr and you can do absolutely anything with macros anywhere, then two programmers might not really be able to communicate even if they are technically using the same language.