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2 points by jsg 4437 days ago | link | parent

I agree. macro transformers would need to refer to the lexical context in which they were defined. strangely, a number of threads in this forum seem to indicate substantial resistance against implementing Arc macros any way other than as simple list manipulations. now granted that 1) straightforward list transformations are easy to understand, 2) there are limitations with _some_ macro systems that provide for lexical references to identifiers in the definition context, 3) inadvertently shadowing identifiers appearing in macroexpansions is unlikely in _other_ Lisps thanks to multiple namespaces, package systems and restrictions on shadowing certain identifiers, and 4) it is a lot more difficult to correctly implement a macro system that solves this problem. however, let's all agree that a hypothetical macro system that _could_ solve this problem would be vastly preferable. arguing against this on the grounds that accidentally shadowing identifiers is a problem you're willing to deal with manually (in a single-namespace Lisp with no module system and no shadowing restrictions) is analogous to arguing in favor of dynamic scoping over lexical scoping as a sensible default.