[cl-who-devel] Generating html tree with dynamic structure

[Ala'a (cmo-0)]

this is a my first shot. I do not know what is an s-tree, thus the
implementation of 'text-style'

(defmethod p-render-html ((s-tree tree) (p text-piece) stream)
  (with-html-output (stream nil :prologue nil)
    (let ((text (text-of p)))
      (if (styled-p text-piece)
          (styled-str text )
          (str text)))))

(defun styled-p (text-piece)
  (if (style-of text-piece) t nil))

(defun styled-str (text)
  (dolist (style (text-styles text))
    (setf text (apply-style style text)))
  text) ;; or you can use recursive style

;; this is only for light testing
(defun text-styles (text)
  (list 'italic 'bold))

;; you may change the internals to a macro (aka defstyle ) based for
example on a hastable of lambdas
;; rather than using and maintaining/updating ecase form manually
(defun apply-style (style text)
  (with-output-to-string (out)
    (with-html-output (out nil :prologue nil)
      (ecase style
        ('italic (htm (:italic (str text))))
        ('bold (htm (:strong (str text))))))))

Regards,

Ala'a (cmo-0)

On Mon, Nov 23, 2009 at 8:37 PM, Dmitry V'yal <akamaus at gmail.com> wrote:
> Hello anyone,
>
> I have a simple problem, but I can't find an elegant solution.
>
> Basically I have a message and two flags, the first one signals message
> should be rendered in <strong> tag and the second - in <italic>. So
> there are four possibilities.
>
> Here is the actual code:
>
> (defmethod p-render-html ((s-tree tree) (p text-piece) s)
>   (with-html-output (s nil :prologue nil)
>     (let ((style (style-of p))
>           (txt (text-of p)))
>       (if style
>           (if (tree-find-prop s-tree style #'bold)
>               (htm (:strong (if (tree-find-prop s-tree style #'italic)
>                                 (htm (:italic (str txt)))
>                                 (str txt))))
>               (if (tree-find-prop s-tree style #'italic)
>                   (htm (:italic (str txt)))
>                   (str txt)))
>           (str txt)))))
>
> I had to test for each case and it resulted in code duplication. Can it
> be avoided? What if I had 5 flags or so?
>
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-- 
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