June 2, 2005
11:51 a.m.
?!ng: Well, i should refine that a bit to say that the Lisp macro system is a little more specific. Whereas AST transformations in Python are open-ended (you could generate any result you want), the key interesting property of Lisp macros is that they are constrained to be "safe", in the sense that the bindings of variable names are always preserved.
I'm not quite sure what ?!ng means by "the bindings of variable names are always preserved", but I conjecture that he is thinking of the "hygienic macros" in Scheme rather than the macros in Common Lisp which permit arbitrary code transformations. -- g