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Started by eddier, November 12, 2004, 01:09:32 PM

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eddier

November 12, 2004, 01:09:32 PM Last Edit: December 31, 1969, 04:00:00 PM by eddier
Kind of a macro within macro within ... thingy that really helps with html code.


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(define (<page> %w)
  (replace "`(.+?)`" %w (string (eval-string $1)) 516)
  (if (> $0 0) (<page> %w) %w))

...

(let (isfred true val "fred")
  (print [text]Content-type: text/html

<html>
<body>
<p>`(if test
              "Hello `val`!"
              "You are not `val`!")`</p>
</body>
</html>[/text]))


Three things to notice,

  1. Lutz was right about using 512 in replace when nesting. Notice `val` nested within the `(if ...)`

  2. I added 4 because I needed to match across newlines.

  3. I didn't see a post-test loop for newlisp in reference manual. I was fooled by (until ) until I noticed that it meant (while (not ...  Still a pre-test loop. The recursive version of (<page> %w) would be a one liner using something like
Code Select

(define (<page> %w)
  (repeat (> $0 0) (replace "`(.+?)`" %w (string (eval-string $1)) 516)))


Would a post-test loop construct be usefull for anyone else? I try to stay functional for the most part, but here, an imperative construct seems to be most natural.



What do you think Lutz?



Eddie

Lutz

#1
November 12, 2004, 01:50:27 PM Last Edit: December 31, 1969, 04:00:00 PM by Lutz
Looking into the code, it would be trivial to add, it could be 'do-while' and 'do-until' for post-test versions of 'while' and 'until'. Occasionally I also felt the urge to have it.



But I wonder how others feel about it?



Lutz

lwix

#2
November 14, 2004, 01:08:27 PM Last Edit: December 31, 1969, 04:00:00 PM by lwix
+1    (i.e. "yes" to having them added)
small\'s beautiful

eddier

#3
November 15, 2004, 11:43:35 AM Last Edit: December 31, 1969, 04:00:00 PM by eddier
Correction. To handle both nesting of "<% %>"s and sequences of "<% %>"s, change the substitute code to
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(define (subs %w)
  (replace "(<%([^<%]+?)%>)" %w (string (eval-string $2)) 0)
  (if (> $0 0) (subs %w) %w))

(setq iftest true dotrue "hello" dofalse "goodbye")
(setq text [text]<p><%(if <%iftest%> "<%dotrue%>" "<%dofalse%>")%></p>[/text])

(println (subs text))

(exit)
=> "<p>hello</p>"

Note the only non-greedy part should be inside of the closest "<% %>" pairs, not outside.



Eddie

eddier

#4
November 15, 2004, 11:45:36 AM Last Edit: December 31, 1969, 04:00:00 PM by eddier
OOPS! Use the following.
Code Select

(define (subs w)
  (replace "<%([^<%]+?)%>" w (string (eval-string $1)) 0)
  (if (> $0 0) (subs w) w))


Eddie
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