Gotchas!
=======

All items for a page *must* be part of a list!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

   OK:     (list (function1 param1)(function2 param2))
   NOT OK: (begin (function1 param1)(function2 param2))


Various components
~~~~~~~~~~~~~~~~~~

The URL:

http://the.domain.com/pagename/p1/p2/p3?param1=value1

(s:get-page-params) => '("p1" "p2")

(s:get-param 'param1) => "value1"
(s:get-param 'param1 'number) => number or #f 

Create a link.
~~~~~~~~~~~~~~

(s:a name 'href 
    (s:link-to "pagename/blah" ""))

Call current page with new param
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In view.scm:

 (s:center "[" (s:a 'href (s:link-to "polls"
                           'id
                            (begin
                              (poll:poll 'fill-polls)
                              (poll:poll 'get-next-poll)))
                          "Go to the next poll")  "]")

In control.scm:

(let ((poll-id (s:get-param 'id)))
 ;; do stuff based on poll-id


Call an action on a specific page
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 (s:a 'href (s:link-to "polls" 'id (poll:poll 'get 'id) 
			       'action "poll.edit")
            "Suggest changes to this poll")

 NOT TRUE! This calls fuction poll.edit (should be in control.scm). Parameter set is 'id to a poll num.


A complex link example
~~~~~~~~~~~~~~~~~~~~~~

(s:a "Reply" 'href (s:link-to (s:current-page) 
	           'action "discussion.reply" ;; <page>.<action>
	           'reply_to (number->string (hash-table-ref row 'posts.id)) 
	           'id (s:get "discussion.parent_object_id")) "reply")

;; use (s:get-param to get the 'id, or 'reply_to values


Get and set a session var
~~~~~~~~~~~~~~~~~~~~~~~~~

(s:session-var-get "keyname")
(s:session-var-get "keyname" 'number) 
(s:session-var-set! "keyname" "value")

5.1 Page local vars

(s:set! key val)
(s:get key)


make a selection drop down
~~~~~~~~~~~~~~~~~~~~~~~~~~

;; items is a hierarchial alist
;; ( (label1 value1 dispval1 #t) ;; <== this one is selected
;;   (label2 (label3 value2 dispval2)
;;           (label4 value3 dispval3)))

In view.scm: 

;;                                   Label   Value visible-str selected
(s:select '(("World" 0)("Country" 1)("State" 2     "The state" #t       )("Town/City" 3)) 'name 'scope)

Visible str will be shown if provided. Selected will set that entry to pre-selected.

To select a specific entry:

(s:select '(("World" 0 "world" #f)("Country" 1 "country" #t)("State" 2 "state" #f)("Town/City" 3 "town" #f)) 'name 'scope)

In control.scm:

(let ((scope     (s:get-input 'scope))
      (scope-num (s:get-input 'scope 'number))) ;; 'number, 'raw or 'escaped
  ....

The optional fourth entry sets that item as selected if true

Simple error reporting
~~~~~~~~~~~~~~~~~~~~~~

In control.scm:
(s:set-err "You must provide an email address")

In view.scm:
(s:get-err s:err-font)

Or:
(s:get-err (lambda (x)(s:err-font x (s:br))))


Sharing data between pages
~~~~~~~~~~~~~~~~~~~~~~~~~~

NOTE: This data is *not* preserved between cgi calls.

;; In first page called
(s:shared-set! "somekey" somevalue)

;; In a page called later
(let ((dat (s:shared-get "somekey")))
  ( .... ))


Misc useful stuff
~~~~~~~~~~~~~~~~~

  i. Lazy/safe string->number 

(s:any->number val)

  ii. Random string

(session:make-rand-string len)

 iii. string to number for pgint
 
(s:any->pgint val)


Forms and input
~~~~~~~~~~~~~~~

(s:form 'action "login.login" 'method "post"
   (s:input-preserve 'type "text" 'name "email-address" 'size "16" 'maxlength "30")
   (s:input 'type "submit"   'name "form-name" 'value "login"))

(s:get-input 'email-address)

To preserve the input simply do a set of the value on the 'name field:
(s:set! "email-address" "matt@kiatoa.com")

Radio buttons:

	(s:div 'class "col_3"
		       (s:input 'type "radio" 'id "group-type1" 'name "group-type" 'value "private" 'checked "checked")
		       (s:label 'for "group-type1" 'class "inline" "Private")
		       (s:input 'type "radio" 'id "group-type2" 'name "group-type" 'value "public")
		       (s:label 'for "group-type2" 'class "inline" "Public"))

       (s:get-input 'group-type) ==> returns private or public depending on which is selected.