Subject: Re: Is DSSSL Syntax Tricky? From: Paul Prescod <papresco@xxxxxxxxxxxxxxxxxxxxxxxxx> Date: Tue, 20 May 1997 14:30:44 -0400 (EDT) |
I just realized that it isn't really fair to ask if people were familiar with the map idiom because map isn't in Jade. You would have had to already understand recursion and higher order functions to implement it. Here's the implementation for those who want to try to start using it: (define (map func lst) (let loop((lst lst)) (if (null? lst) '() (cons (func (car lst)) (loop (cdr lst)))))) It really is a wonderfully powerful procedure that can take much of the sting out of functional programming. Any time you need to do something to all elements of a list, node-list or string, you can convert it to a list, write a little function that does the "thing", use the function as the first argument and the list as the second, map will return a list. Then you use "apply" to use that list as the arguments to some function, like string, string-append or sososo-append. The nature of DSSSL stylesheets makes the procedure useful quite often (for iterating over children, for instance). Please consider this a feature request, James. =) Paul Prescod DSSSList info and archive: http://www.mulberrytech.com/dsssl/dssslist
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