On Wed, 2009-01-14 at 11:06 -0800, Max Rabkin wrote: > On Wed, Jan 14, 2009 at 10:48 AM, Jonathan Cast > <[email protected]> wrote: > > Do you have an example of > > a macro that can't be replaced by higher-order functions and laziness? > > I believe I do: one macro I found useful when writing a web app in > Lisp was something I called hash-bind, which binds variables to the > values in a hashtable, with the variable names as keys. For example: > > (hash-bind (a b) hashtable body) > == > (let > ((a (lookup hashtable "a")) > (b (lookup hashtable "b")) > body) > > I found this very useful in places where I was given URL request > parameters in a hashtable and wanted to extract some variables from > it. I don't believe it can be replaced by a higher order function > (though I may be wrong).
Thanks! When you *know* there's a good reason people say something, and can't find a good example of *why*, it's a tremendous relief when when you find one. Sort of restores your faith in humanity :) jcc _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
