Dietrich

Sorry, the Mono was in there to show that is is similar to NET. I am quite sure Bill hates open source Mono.

Macros have always been frowned upon in the C community as a good source of nasty errors, but then C# code can be a little long winded! Who wouldn't like to write "print x" rather than "System.Console.WriteLine(x)".

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I looked it up on the Intergnats!

Arevos

C macros aren't true macros in the Lisp sense. Lisp and Boo macros are a method of redefining, or adding to, the grammar of the language on the fly. This makes macros very, very powerful constructs, as you might well imagine. So far as I know, Boo is the only existing procedual language that has this ability.

Boo macros are also likely to be more robust than C's. In C, macros are simple substitutions done at compile time. In Boo, they're object-orientated extensions to the parser.

Dietrich

I went back to the Boo site and looked at the macro information there. It's pretty sparse. Where did you find your information? It makes macros indeed more interesting!

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I looked it up on the Intergnats!

Arevos

There's some information on Boo macros here and some examples here.

I've dug about in Lisp a bit, so I could recognise the similarity between Boo macros and those in Lisp. When most languages are compiled, they are first construsted into an AST or Abstract Syntax Tree. For instance, the expression "x + 1" might evaluate into a AST that looks like:
Macros are language constructs used to manipulate parts (subtrees) of the AST. They first cropped up in Lisp some decades back, and Boo has the same ability. In Boo, macros seem to have the syntax:
When the block of code is parsed into an AST, the AST object is passed to the macro for extra processing. The macro can manipulate the subtree AST in any way it wishes. Presumably, one could even store bits of it for later.

This allows the programmer to dynamically create localised syntax extensions to the language during runtime.

I'm unsure quite how flexible Boo's macro system is, and how much it checks the AST before passing it on to the macro, but in theory, one might be able to do something like this:
At least, that's what an ideal macro system would be able to do.

Dietrich

Thanks,

looks like one has to read between the lines, after one gets through all that endless legal mumbo jumbo. Looks like there are 100 lines of copyright messages for every line of code published. Does a simple print "Hello!" really need all that legal stuff, or are we dealing with rather strange folks?

I tried to run some of the given examples, but most don't work because of missing import modules/namespaces. Where on earth is Boo.IO? Maybe a few years down the road Boo will have the act together.

I downloaded Boodle, a sweet little IDE for Boo. That one actually works well!

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I looked it up on the Intergnats!