WML II (“Son of WML”) WML WMLScript

WML - A Quick Review Document structure ,... Text and image controls ...,,..., Navigation controls ,,, Events  onenterforward, onenterback, ontimer  ...,... Variables , $(foo)

WML - Examples A minimal WML file Hello world!

WML - Examples Loading an image-- Hello world!

WML - Examples Using a softkey-- Hello world! Hello world!

WML - Examples Using a link-- Hello world! Link to Card 2 Hello world!

WML - Examples Using a timer-- Hello world! Hello world!

WML - Examples Table layout-- Hello world!

WML - Input Revisited Last name : Gender : Female Male Display Welcome, $(salutation) $(name), to my wireless underground volcano lair.

WML - Input Revisited The tag:  Use to record variable user input  name="variable" : required  Can specify format ex: “NNNNN” maps to exactly five digits. “NNaaaa” maps to two digits followed by four letters. The phone won’t accept anything else.  Can specify type=“password” for secure (ie hidden) entry  Can specify maxlength=“...” for the max number of characters of data the user can enter  How the phone chooses to render the input box is up to the phone. Don’t depend on there being, say, a little black box.

WML - Input Revisited The tag:  Use to limit user entry between several possible options  Can be used for links, as well  name="variable” is optional; can just use onpick (below).  multiple=“true” or “false” : allow multiple selections. In the case of multiple selections, the values are stored as a semicolon-delimited list.  value=“...” : sets the default value of the tag’s variable The tag:  Defines a single entry in a  value=“...” determines the value that this option sets for the variable named by the enclosing tag  onpick=“url” : when the user selects this option, links directly to another card or page.  You can also catch “onpick” events from the tag.

WML - Input as Navigation Choose a lair: Volcano Underground Welcome to my wireless volcano lair. Welcome to my wireless underground lair.

WMLScript WMLScript is similiar to JavaScript in function; it allows a more powerful and controllable degree of scripting control than offered by simple WML. WMLScript offers a decent range of string- manipulating and mathematical functions. Each WMLScript file is full of functions. Each function is either local--used only within the file-- or external--accessible from other WMLS and WML files.  To declare a function extern, put the word extern before its declaration.

WMLScript - Functions Within each function, you’ll write WMLScript code. Syntax:  var n = 1; // Declares a variable named ‘n’  n = 2; // Assigns n the value 2  if (n==3)... // Test if n equals 3. // Note that ‘=‘, assignment, is not the // same as ‘==‘, which tests equality.  You’ve got the full set of if-then tests, loops and so on... for (var index = 0; index < 100; index++) { myFunc(index); };

WMLScript - Functions Declaring a function of your own:  Ex: extern function getHello() { return “hello!”; }  Ex: extern function addOne(n) { return n+1; }  Ex: extern function addVals(n, m) { return n+m; }

WMLScript - Functions When you declare a function, it can call other functions: extern function myFunc() { var n = 2;// Initialise n to 2 n = myOtherFunc(n);// Call myOtherFunc() return n; // n is now 4 (n * n) } function myOtherFunc(n)// Note--not extern { return n * n;// Take n and return n squared }

WMLScript - Functions The WMLScript Libraries:  Lang (miscellaneous routines)  Float (real numbers)  String (character string manipulation)  URL (HTTP string routines)  WMLBrowser (browser interraction)  Dialogs (user interraction)  Console (debug output) Each library defines a set of functions that can be called from your code. For details on each library, consult the reference materials online.

WMLScript - Functions A few common standard library routines:  WMLBrowser.getVar( )// gets a var’s value  WMLBrowser.setVar(, )// sets a var’s value  WMLBrowser.refresh()// reload this page  WMLBrowser.go(url)// go to a url  Lang.isInt( )// Test for a number  Lang.parseInt( )// Convert to a number Some common language statements:  if ( ) else  for ( ; ; )...  while ( )...  return ;// Sets the value of // a function call

WMLScript - Calling WMLS from WML Value : $(myVar) Click here to increment the value. extern function increment() { var myVar = WMLBrowser.getVar("myVar"); WMLBrowser.setVar("myVar", myVar + 1); WMLBrowser.refresh(); } What will this code do?

WMLScript - Calling WMLS from WML extern function increment() { var myVar = WMLBrowser.getVar("myVar"); WMLBrowser.setVar("myVar", myVar + 1 ); WMLBrowser.refresh(); } What’s going on here?

WMLScript - What happened back there? Variable types  The problem was that variables in WMLScript don’t have a type associated with them. WMLS doesn’t know whether they’re character strings or numbers.  Since “+” will add two numbers or glue together two strings (1+1=2, but ‘abc’+’def’=‘abcdef’), WMLS just assumed we wanted string concatenation.  To make sure we use integer math, use the Lang library’s toInt() function to force the variable type to an integer: extern function increment() { var myVar = WMLBrowser.getVar("myVar"); if (!Lang.isInt(myVar)) myVar = 0; WMLBrowser.setVar("myVar", Lang.parseInt(myVar) + 1); WMLBrowser.refresh(); }

WMLScript - Initialisation and conditions Initialising a variable in WML: Value : Click here to test the value. The value is $(myOddity).

WMLScript - Initialisation and conditions Testing a value in WMLS: extern function testValue() { var myVar = Lang.parseInt(WMLBrowser.getVar("myVar")); if (((myVar / 2) * 2) == myVar) WMLBrowser.setVar("myOddity", "even"); else WMLBrowser.setVar("myOddity", "odd"); WMLBrowser.refresh(); } And the result:

WMLScript - Recursion “Recursion”  Recursion is the term for when a function calls itself. When you write recursive code, take care : make sure that there’s always a way out!  Ex: In mathematics, the phrase “N factorial” means “if N is some number, then multiply all of the numbers from 1 to N together”. You could say that a little more easily as “if N is some number, then multiply N times N minus one, factorial”. You’ve defined factorial in terms of itself. The shorthand for factorial is !. “N!” is “N factorial”. In other words, N!= N * (N-1)!.

WMLScript - Recursion Recursion - N Factorial (example)  N!: extern function recurseFactorial(n) { if (n > 1) return n * recurseFactorial(n-1); else return n; }  This defines N! in code. When you call recurseFactorial(n), it checks n; if n is greater than one, it calculates (n-1)! and then multiplies n onto the total. Since n-1 must eventually reach 1, eventually we’ll fall out of the loop.  Of course, that’s only true if n >= 1, right?

WMLScript - Recursion Enter N : Click here to find N! ("N factorial"). N! = $(nFact). extern function factorial() { var n = Lang.parseInt(WMLBrowser.getVar(" n")); if (n < 0) n = 0; WMLBrowser.setVar("nFact", recurseFactorial(n)); WMLBrowser.refresh(); } extern function recurseFactorial(n) { if (n > 1) return n * recurseFactorial(n- 1); else return n; }

Bibliography WML Language Reference:  WMLScript Reference:  All code used is available on the J: drive. No variables were harmed in the making of this lecture.