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+---- Thread: [Source] R5RS Scheme (Racket/LISP) S-expression to XML converter (/showthread.php?tid=6196235)
R5RS Scheme (Racket/LISP) S-expression to XML converter - MiguelSanchez - Mar 5, 2022
I'm going to make a nice animated SVG generator, rather then outputting html I'm going to output normal s-expressions which I've just writing homomorphically to XM anyway to preserve a direct mapping.
It's just this way I'll have macros and quasiquotes in HTML and SVG.
It's short
Code
(define (->str s) (if (string? s) (string-append "\"" s "\"") (if (number? s)(number->string s) (symbol->string s))))
(define (pair->xml p) (string-append " " (symbol->string (car p)) "=" (->str (cdr p)) ))
(define (s-expression->xml-inner exp) (if (string? exp) exp (string-append "<" (symbol->string (car exp)) (apply string-append (map pair->xml (cadr exp))) ">" (s-expression->xml (cddr exp)) "</" (symbol->string (car exp)) ">")))
(define (s-expression->xml exps) (if (null? exps) "" (string-append (s-expression->xml-inner (car exps)))))
(define (demo duration) `((svg
((viewbox . "0 0 10 10") (xmlns . "http://www.w3.org/2000/svg"))
(rect
((width . 7) (height . 10))
(animate ((attributeName . "width") (values . "7;10;7") (dur . ,duration) (repeatCount . "indefinite")))))))
(display (s-expression->xml (demo "5s")))I've got a basic animated SVG demo function named demo, it just takes duration as a variable so I could show the syntax for unquoting a variable in the quasiquote, everything following ` is a quote,it means I'm talking about the literal symbols not what they represent, unless proceeded by a comma (like duration is) which means I'm referring to the variable duration's assigned value not the literal name 'duration.
I'll turn this into a tight banner making library soon, and I'll be back for business (with free vouch copies of custom banners when I do)