\chapter Built-in Types and Objects

\QS provides a variety of types and built-in objects. The types
covered in the following sections are built into the \QS interpreter.

The built-in types include \l Array, \l Boolean, \l Date, \l{Function
type} \l Number, \l Object, \l Point, \l Rect, \l RegExp, \l Size, \l
String, \l Color, \l Palette, \l ColorGroup, \l ByteArray, \l Font and
\l Pixmap.

The built-in objects include \l Math and \l System. 

\section1 Built-in Types

These are in some sense, \QS's 'native' datatypes. 

\section2 Array

An \Class Array is a datatype which contains a named list of
items. The items can be any \QS object. Multi-dimensional arrays
are achieved by setting array items to be arrays themselves.

Arrays can be extended dynamically simply by creating items at
non-existent index positions. Items can also be added using \c
push(), \c unshift() and \c splice(). Arrays can be concatenated
together using \c concat(). Items can be extracted using \c pop(),
\c shift() and \c slice(). Items can be deleted using \c splice().
Arrays can be turned into strings using \c join() or
\c{Array::toString()}. Use \c reverse() to reverse the items in an
array, and \c sort() to sort the items. The \c sort() function can
be passed a comparison function for customized sort orders.

In general, operations that copy array items perform a deep copy on
items that are \c Number or \c String objects, and a shallow copy
on other objects.

\section3 Array Construction

Arrays can be constructed from array literals or using the \l{new
operator}:
\code
    var mammals = [ "human", "dolphin", "elephant", "monkey" ];
    var plants = new Array( "flower", "tree", "shrub" );
    var things = [];
    for ( i = 0; i < mammals.length; i++ ) {
	things[i] = new Array( 2 );
	things[i][0] = mammals[i];
	things[i][1] = plants[i];	
    }
\endcode

Arrays can be initialized with a size, but with all items
undefined:
\code
    var a = new Array( 10 ); // 10 items
\endcode

\section3 Array Access

\Class Array items are accessed via their names. Names can be either
integers or strings. 

Example:
\code
    var m2 = mammals[2];
    mammals[2] = "gorilla";
    var thing = things[2][1]
\endcode
The first statement retrieves the value of the third item of the \c
mammals array and assigns it to \c m2, which now contains "monkey".
The second statement replaces the third item of the \c mammals
array with the value "gorilla". The third statement retrieves the
second item of the third item's array from the \c things array
and assigns it to \c thing, which now contains "shrub".

As stated above, it is also possible to access the arrays using
strings. These act as normal properties, and can be accessed either
using the square bracked operator ([]) or by directly dereferencing
the array object and specifying the property name (.name). These two
accessor types can be mixed freely as seen below with the \c address
and \c phoneNumber properties.

\code
    var names = [];
    names["first"] = "John";
    names["last"] = "Doe";
    var firstName = names["first"];
    var lastName = names["last"];
   
    names["address"] = "Somewhere street 2";
    names.phoneNumber = "+0123456789";
    var address = names.address;
    var phoneNumber = names["phoneNumber"];
\endcode

\section3 Array Properties

\list 

\o length : Number; Holds the number of items in the array. Items with
string keys are excluded from the length property.

\endlist

\section3 Array Functions

\list

\o concat( a1 : Array, a2 : Array ... aN : Array) : Array;
\code
    var x = new Array( "a", "b", "c" );
    var y = x.concat( [ "d", "e" ], [ 90, 100 ] );
    // y == [ "a", "b", "c", "d", "e", 90, 100 ]
\endcode

Concatenates the array with one or more other arrays in the order
given, and returns a single array.

\o join( optSeparator : String ) : String; 
\code
    var x = new Array( "a", "b", "c" );
    var y = x.join();         // y == "a,b,c"
    var z = x.join( " * " );  // y == "a * b * c"
\endcode

Joins all the items of an array together, separated by commas, or by
the specified \c optSeparator.

\o pop() : Object;
\code
    var x = new Array( "a", "b", "c" );
    var y = x.pop(); // y == "c"  x == [ "a", "b" ]
\endcode
Pops (i.e. removes) the top-most (right-most) item off the array and
returns it.

\o push( item1, optItem2, ... optItemN );
\code
    var x = new Array( "a", "b", "c" );
    x.push( 121 ); // x == [ "a", "b", "c", 121 ]
\endcode
Pushes (i.e. inserts) the given items onto the top (right) end of the
array. The function returns the new length of the array.

\o reverse();
\code
    var x = new Array( "a", "b", "c", "d" );
    x.reverse(); // x == [ "d", "c", "b", "a" ]
\endcode
Reverses the items in the array.

\o shift() : Object; 
\code
    var x = new Array( "a", "b", "c" );
    var y = x.shift(); // y == "a"  x == [ "b", "c" ]
\endcode
Shifts (i.e. removes) the bottom-most (left-most) item off the array
and returns it.

\o slice( startIndex : Number, optEndIndex : Number ) : Array;
\code
    var x = new Array( "a", "b", "c", "d" );
    var y = x.slice( 1, 3 ); // y == [ "b", "c" ]
    var z = x.slice( 2 );    // z == [ "c", "d" ]
\endcode
Copies a slice of the array from the item with the given starting
index, \c startIndex, to the item \i before the item with the given
ending index, \c optEndIndex. If no ending index is given, all items
from the starting index onward are sliced.

\o sort( optComparisonFunction : function );
\code
    var x = new Array( "d", "x", "a", "c" );
    x.sort(); // x == [ "a", "c", "d", "x" ]
\endcode

Sorts the items in the array using string comparison. For
customized sorting, pass the \Func sort() function a comparison
function, \c optComparisonFunction, that has the following signature
and behavior:

\code
    function comparisonFunction( a, b ) // signature
\endcode

The function must return an integer as follows:
\list
\o -1 if a \< b
\o  0 if a == b
\o  1 if a \> b
\endlist

Example:
\code
    function numerically( a, b ) { return a < b ? -1 : a > b ? 1 : 0; }
    var x = new Array( 8, 90, 1, 4, 843, 221 );
    x.sort( numerically ); // x == [ 1, 4, 8, 90, 221, 843 ]
\endcode

\o splice( startIndex : Number, replacementCount : Number, optItem1, ... optItemN );
\code
    var x = new Array( "a", "b", "c", "d" );

    // 2nd argument 0, plus new items   ==> insertion
    x.splice( 1, 0, "X", "Y" );
    // x == [ "a", "X", "Y", "b", "c", "d" ]

    // 2nd argument > 0, and no items   ==> deletion
    x.splice( 2, 1 );
    // x == [ "a", "X", "b", "c", "d" ]

    // 2nd argument > 0, plus new items ==> replacement
    x.splice( 3, 2, "Z" );
    // x == [ "a", "X", "b", "Z" ]
\endcode
Splices items into the array and out of the array. The first
argument, \c startIndex, is the start index. The second argument, \c
replacementCount, is the number of items that are to be replaced.
Make the second argument 0 if you are simply inserting items. The
remaining arguments are the items to be inserted. If you are simply
deleting items, the second argument must be \> 0 (i.e. the number of
items to delete), and there must be no new items given.

\o toString() : String;
\code
    var x = new Array( "a", "b", "c" );
    var y = x.toString();  // y == "a,b,c"
    var z = x.join();      // y == "a,b,c"
\endcode
Joins all the items of an array together, separated by commas. This
function is used when the array is used in the context of a string
concatenation or is used as a text value, e.g. for printing. Use \c
join() if you want to use your own separator.

\o unshift( expression : String, optExpression1, ... opExpressionN )
\code
    var x = new Array( "a", "b", "c" );
    x.unshift( 121 ); // x == [ 121, "a", "b", "c" ]
\endcode
Unshifts (i.e. inserts) the given items at the bottom (left) end of
the array.

\endlist

\section2 Boolean

\ECMA provides a \Class Boolean data type. In general, creating objects
of this type is not recommended since the behavior will probably not
be what you would expect.

Instead, use the boolean constants \c true and \c false as required.
Any expression can be evaluated in a boolean context, e.g. in an \l if
statement. If the expression's value is \c 0, \c null, \c false, \l
NaN, \l undefined or the empty string \c "", the expression is \c
false; otherwise the expression is \c true.


\section2 Date

Instances of the \Class Date class are used to store and manipulate
dates and times.

A variety of get functions are provided to obtain the date, time or
relevant parts, for example, \c getDay(), \c getYear(), \c getHours(),
\c getMilliseconds(), \c getMinutes(), \c getMonth(), \c getSeconds(),
\c getTime().

A complementary set of functions are also provided, including \c
setYear(), \c setHours(), \c setMilliseconds(), \c setMinutes(), \c
setMonth(), \c setSeconds(), \c setTime().

The functions operate using local time.

Conversion between Date objects to and from strings are provided by \c
parse() and \c Date::toString().

Elapsed time (in milliseconds) can be obtained by creating two dates,
casting them to \c Number and subtracting one value from the other.
\code
var date1 = new Date();
// time flies..
var date2 = new Date();
var timedifference = date2.getTime() - date1.getTime();
\endcode

\section3 Static Date Functions

\list

\o parse( dateString : String ) : Number;
\code
    var d = new Date( Date.parse( "1976-01-25T22:30:00" ) );
    d = Date.parse( "1976-01-25T22:30:00" );
\endcode
This is a static function that parses a string, \c dateString, which
represents a particular date and time. It returns the number of
milliseconds since midnight on the 1st January 1970. The string must
be in the ISO 8601 extended format: \c{YYYY-MM-DD} or with time
\c{YYYY-MM-DDTHH:MM:SS}.

\endlist

\section3 Date Construction

\code
Date()
Date( milliseconds )
Date( year, month, day, optHour, optMinutes, optSeconds, optMilliseconds )
\endcode

\code
    var today = new Date();
    var d = new Date( 1234567 );
    var date = new Date( 1994, 4, 21 );
    var moment = new Date( 1968, 5, 11, 23, 55, 30 ); 
\endcode 

Dates can be constructed with no arguments, in which case the value is
the date and time at the moment of construction using local time. A
single integer argument is taken as the number of milliseconds since
midnight on the 1st January 1970.

\section3 Date Functions

\list

\o getDate() : Number; 
\code
    var d = new Date( 1975, 12, 25 );
    var x = d.getDate();  // x == 25
\endcode
Returns the day of the month using local time. The value is always in
the range 1..31.

\o getDay() : Number; 
\code
    var d = new Date( 1975, 12, 25, 22, 30, 15 );
    var x = d.getDay();  // x == 4
\endcode
Returns the day of the week using local time. The value is always in
the range 1..7, with the week considered to begin on Monday.

Example:
\code
    var IndexToDay = [ "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun" ];
    var d = new Date( 1975, 12, 28 );
    System.println( IndexToDay[ d.getDay() - 1 ] ); // Prints "Sun"
\endcode

\o getYear() : Number;
\code
    var d = new Date( 1975, 12, 25 );
    var x = d.getYear();  // x == 1975
\endcode

Returns the year using local time.

\o getHours() : Number;
\code
    var d = new Date( 1975, 12, 25, 22 );
    var x = d.getHours();  // x == 22
\endcode
Returns the hour using local time. The value is always in the range
0..23.

\o getMilliseconds() : Number;
\code
    var d = new Date( 1975, 12, 25, 22 );
    var x = d.getMilliseconds();  // x == 0
\endcode
Returns the milliseconds component of the date using local time. The
value is always in the range 0..999. In the example, \c x is 0,
because no milliseconds were specified, and the default for
unspecified components of the time is 0.

\o getMinutes() : Number;
\code
    var d = new Date( 1975, 12, 25, 22, 30 );
    var x = d.getMinutes();  // x == 30
\endcode
Returns the minutes component of the date using local time. The
value is always in the range 0..59.

\o getMonth() : Number;
\code
    var d = new Date( 1975, 12, 25, 22, 30 );
    var x = d.getMonth();  // x == 12
\endcode
Returns the months component of the date using local time. The
value is always in the range 1..12.

Example:
\code
    var IndexToMonth = [ "Jan", "Feb", "Mar", "Apr", "May", "Jun",
                         "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" ];
    var d = new Date( 1975, 12, 25 );
    System.println( IndexToMonth[ d.getMonth() - 1] ); // Prints "Dec"
\endcode

\o getSeconds() : Number;
\code
    var d = new Date( 1975, 12, 25, 22, 30 );
    var x = d.getSeconds();  // x == 0
\endcode
Returns the seconds component of the date using local time. The
value is always in the range 0..59. In the example \c x is 0 because
no seconds were specified, and the default for unspecified
components of the time is 0.

\o getTime() : Number;
\code
    var d = new Date( 1975, 12, 25, 22, 30 );
    var x = d.getTime();  // x == 1.91457e+11
\endcode
Returns the number of milliseconds since midnight on the 1st January
1970 using local time.

\o setDate( dayOfTheMonth : Number );
\code
    var d = new Date( 1975, 12, 25, 22, 30 );
    d.setDate( 30 );  // d == 1975-12-30T22:30:00
\endcode
Sets the day of the month to the specified \c dayOfTheMonth in local
time.

\o setYear( year : Number );
\code
    var d = new Date( 1975, 12, 25, 22, 30 );
    d.setYear( 1980 );         // d == 1980-12-30T22:30:00
    d.setYear( 1980, 11, 2 );  // d == 1980-12-02T22:30:00
\endcode
Sets the year to the specified \c year in local time. If the month, \i
optMonth is specified, it must be in the range 0..11. If the \i
optDayOfTheMonth is specified it must be in the range 1..31.

\o setHours( hour : Number );
\code
    var d = new Date( 1975, 12, 25, 22, 30 );
    d.setHours( 10 );  // d == 1980-12-30T10:30:00
\endcode
Sets the \c hour to the specified hour, which must be in the range
0..23, in local time. The minutes, seconds and milliseconds past the
hour (\c optMinutes, \c optSeconds and \c optMilliseconds) can also be
specified.

\o setMilliseconds( milliseconds : Number );
\code
    var d = new Date( 1975, 12, 25, 22, 30 );
    d.setMilliseconds( 998 );  // d == 1980-12-30T10:30:00:998
\endcode
Sets the \c milliseconds component of the date to the specified value
in local time.

\o setMinutes( minutes : Number );
\code
    var d = new Date( 1975, 12, 25, 22, 30 );
    d.setMinutes( 15 );  // d == 1980-12-30T10:15:00
\endcode
Sets the \c minutes to the specified minutes, which must be in the
range 0..59, in local time. The seconds and milliseconds past the
minute (\c optSeconds and \c optMilliseconds) can also be specified.

\o setMonth( month : Number );
\code
    var d = new Date( 1975, 12, 25, 22, 30 );
    d.setMonth( 0, 11 );  // d == 1980-01-11T22:30:00
\endcode
Sets the \c month to the specified month, which must be in the range
0..11, in local time. The day of the month (\c optDayOfTheMonth) may
also be specified.

\o setSeconds()

\c{setSeconds( seconds, optMilliseconds )}

\code
    var d = new Date( 1975, 12, 25, 22, 30 );
    d.setSeconds( 25 );  // d == 1980-12-30T22:30:25
\endcode
Sets the \c seconds to the specified seconds, which must be in the
range 0..59, in local time. The milliseconds past the minute (\i
optMilliseconds) can also be specified.

\o setTime( milliseconds : Number );
\code
    var d = new Date( 1975, 12, 25, 22, 30 );
    var duplicate = new Date();
    duplicate.setTime( d.getTime() );
\endcode
Sets the date and time to the local date and time given in terms of
\c milliseconds since midnight on the 1st January 1970.

\o toString() : String;
\code
    var d = new Date( 1975, 12, 25, 22, 30 );
    var s = d.toString(); // s == "1975-12-25T22:30:00"
\endcode

\endlist

Converts the date into a string on the ISO 8601 extended format:
\c{YYYY-MM-DDTHH:MM:SS}.


\section2 Function Type

Functions are normally defined in the application's source code. In
some situations it is desirable to create functions at run time.

\code
    var min = new Function( "x", "y", "return x < y ? x : y;" );
    var m = min( 68, 9 ); // m == 9
\endcode

The first arguments are the names of the parameters; the last argument
is a string which contains the function's definition. It is also
possible to supply the list of argument names as one comma separated string.

\code
    var min = new Function( "x,y", "return x < y ? x : y;" );
\endcode

Variable numbers of arguments are also supported, using the \l
arguments array, for example:
\code
    max = new Function(
	  "var max = 0;"
	+ "for ( var i = 0; i < arguments.length; i++ ) {"
	+ "   if ( arguments[ i ] > max ) max = arguments[ i ];"
	+ "}"
	+ "return max;"
	);
    System.println( max( 50, 16, 24, 99, 1, 97 ) ); // Prints 99
\endcode

\section2 Number

A \Class Number is a datatype that represents a number. In most
sittuations, programmers will use numeric literals like 3.142 directly
in code. The \Class Number datatype is useful for obtaining system
limits, e.g. \c MIN_VALUE and \c MAX_VALUE, and for performing number
to string conversions with toString()

\section3 Number Construction

Numbers are not normally constructed, but instead created by simple
assignment, e.g.
\code
    var x = 3.142;
\endcode

\section3 Number Properties

\list

\o MAX_VALUE : Number; The maximum value for floating point values.

\o MIN_VALUE : Number; The minimum value for floating point values.

\endlist

A numeric variable can hold a non-numeric value, in which case \l
isNaN() returns \c true. The result of an arithmetic expression may
exceed the maximum or minimum representable values in which case the
value of the expression will be \l Infinity, and \l isFinite() will
return \c false.

\section3 Number Functions

\list 

\o toString() : String; Returns the number as a string value.

\endlist


\section2 Object

An \Class Object is the base type for all \QS objects.

\Class Object provides a \Func toString() function which is usually
overridden by subclasses.

\section2 Point

The \Class Point class provides an implementation of a two dimensional point.

The Point class provides three different constructors.

\code
    var point = new Point( 20, 30 );
    var duplicate = new Point( point ); // 20, 30
    var zero = new Point();		// 0, 0
\endcode

\section3 Point Properties

\list

\o x : Number; The x position of the point.

\o y : Number; The y position of the point.

\endlist

\code
    var p = new Point( 100, 200 );
    System.println( "Point is: " + p.x + ", " + p.y );
\endcode

\section2 Rect

A \Class Rect object represents a rectangle.

The rectangle class provides three constructors.
\code
    var rect = new Rect( 10, 20, 30, 40 ); // x=10, y=20, width=30, height=40
    var duplicate = new Rect( rect );	   // x=10, y=20, width=30, height=40
    var empty = new Rect();		   // x=0, y=0, width=0, height=0
\endcode

\section3 Rect Properties

\list 

\o x : Number; The left position of the rectangle.

\o y : Number; The right position of the rectangle.

\o width : Number; The width of the rectangle.

\o height : Number; The height of the rectangle.

\o top : Number; The position of the top of the
rectangle. This is defined as \c{ top = y }.

\o bottom : Number; The position of the bottom of the
rectangle. This is defined as \c{ bottom = y + height + 1 }.

\o left : Number; The position of the rectangle's left
side. This is defined as \c{ left = x }

\o right : Number; The position of the rectangle's right
side. This is defined as \c{ right = x + width + 1}.

\o center : Point; The center of the rectangle.

\endlist

\section3 Rect Functions

\list

\o isNull() : Boolean; 
\code
    var empty = new Rect();
    empty.isNull(); // true;

    var square = new Rect( 10, 10, 10, 10 );
    square.isNull(); // false;
\endcode
    
Returns true if the rectangle has a width and height of 0.

\o isEmpty() : Boolean; 
\code
    var rect = new Rect( 10, 10, -10, -10 );
    rect.isEmpty(); // true
    
    var rect = new Rect( 10, 10, 10, 10 );
    rect.isEmpty(); // false
\endcode

Returns true if the rectangle is empty, meaning that it has
width and/or height that is negative.

\o contains( otherRect : Rect ) : Boolean;
\code
    new Rect( 0, 0, 100, 100 ).contains( new Rect( 10, 10, 10, 10 ) ); // true
    new rect( 10, 10, 10, 10 ).contains( new Rect( 0, 0, 100, 100 ) ); // false
\endcode

Returns true if the rectangle contains the other rectangle.

\o intersection( otherRect : Rect ) : Rect; Returns the intersection
between this rectangle and another rectangle. The intersection of two
rectangles is the part of the rectangles that overlap. If they do not
overlap, an empty rectangle is returned.

\o union( otherRect : Rect ) : Rect; Returns the union of two
rectangles. The union is a rectangle large enough to encompass both
rectangles.

\o intersects( otherRect : Rect ) : Boolean; Returns true if this
rectangle intersects the other rectangle.

\o normalize(); Normalizes this rectangle. This means changing the
prefix of the width and/or height if they are negative. After being
normalized, a rectangle will no longer be empty.

\o moveLeft( pos : Number ); Moves the rectangle so that its \c left
property is equal to \c pos.

\o moveRight( pos : Number ); Moves the rectangle so that its \c right
property is equal to \c pos.

\o moveTop( pos : Number ); Moves the rectangle so that its \c top
property is equal to \c pos.

\o moveBottom( pos : Number ); Moves the rectangle so that its \c
bottom property is equal to \c pos.

\o moveBy( dx : Number, dy : Number ); Translates the rectangle by \c
dx and \c dy. \c dx and \c dy will be added to \c x and \c y, and \c
width and \c height will be left unchanged.

\endlist

\section2 Size

The \Class Size class represents a two dimensional size. The size is
represented using width and height.

The Size class provides three construtors:
\code
    var size = new Size( 100, 200 ); // width = 100, height = 200
    var duplicate = new Size( size ); // width = 100, height = 200
    var empty = new Size(); // width = 0, height = 0
\endcode

\section3 Size Properties

\list

\o width : Number; The width of the size.

\o height : Number; The height of the size.

\endlist

\section3 Size Functions

\list

\o translate(); The translate function swaps the width and height of the size.

\endlist

\section2 RegExp

A \Class RegExp is a regular expression matcher for strings. 

Regular expressions can be created either by using the
\c{/expression/} syntax or by using the RegExp constructor as shown
below. Note that when using the RegExp constructor, a string is
passed, and all backslashes must be escaped using an extra backslash,
i.e. \c \\d. Below are two ways to create regular expressions that
matches the pattern "QUANTITY=471 # Order quantity" and gets
the number 471.

\code
    var directRegex = /([A-Z]+)=(\d+)/;
    var str = "QUANTITY=471 # Order quantity";
    str.match(directRegex);
    directRegex.capturedTexts[2]; // "471";
	
    var indirectRegex = new RegExp( "([A-Z]+)=(\\d+)" );
\endcode

\section3 RegExp Properties

\list

\o valid : Boolean; Returns true if the regular expression is
syntactically valid; otherwise returns false.

\o empty : Boolean; Returns true if the pattern is empty; otherwise
returns false.

\o matchedLength : Number; The length of the last matched
string, or -1 if there was no match.

\o capturedTexts : String[]; An array of all the captured
texts from the previous match. This can be empty.

\o global : Boolean; Specifies that the regexp should be matched
globally. A global regexp will match every occurrence (i.e. as many
times as possible), whereas a non-global regexp will match at most
once (at the first match it encounters). This is particularly relevant
for replace where every occurance of a pattern will be replaced when
global is true.

A regular expression can be set to global either by setting the global
property on a regexp object or by specifying a trailing \c g in the
pattern.

\code 
var re = /mypattern/g;     // Global by method #1

var re = /mypattern/; 
re.global = true           // Global by method #2
\endcode

\o ignoreCase : Boolean; Specifies that the regexp ignores case
when matching. Case-insensitivity can is enabled by either
specifying a trailing \c i after the pattern or by setting the \c
ignoreCase property.

\code
var re = /mypattern/i;     // Case-insensitive by method #1

var re = /mypattern/;
re.ignoreCase = true;      // Case-insensitive by method #2
\endcode

\endlist

\section3 RegExp Functions

\list

\o toString() : String; Returns the regular expression pattern as a
string.

\o search( text : String ) : Number;
\code
    var re = /\d+ cm/; // matches one or more digits followed by space then 'cm'
    re.search( "A meter is 100 cm long" ); // returns 11
\endcode

Searches \c text for the pattern defined by the regular
expression. The function returns the position in the text of the first
match or -1 if no match is found.

\o searchRev( text : String ) : Number; Same as \c search(), but
searchRev searches from the end of the text.

\o exactMatch( text : String ) : Boolean;
Returns true if \c text exactly matches the pattern in this regular
expresssion; otherwise returns false.

\o cap( nth : Number ) : String;
\code
    re = /name: ([a-zA-Z ]+)/;
    re.search( "name: John Doe, age: 42" );
    re.cap(0);  // returns "name: John Doe"
    re.cap(1);  // returns "John Doe"
    re.cap(2);  // returns undefined, no more captures.
\endcode

Returns the \c nth capture of the pattern in the previously matched
text. The first captured string (\c cap(0) ) is the part of the string that
matches the pattern itself, if there is a match. The following
captured strings are the parts of the pattern enclosed by parenthesis.
In the example above we try to capture \c ([a-zA-Z ]+), which captures
a sequence of one or more letters and spaces after the \c{name:}
part of the string.

\o pos( nth : Number ) : Number;
\code
    re = /name: ([a-zA-Z ]+)/;
    re.search( "name: John Doe, age: 42" );
    re.pos(0); // returns 0, position of "name: John Doe"
    re.pos(1); // returns 6, position of "John Doe"
    re.pos(2); // returns -1, no more captures
\endcode

Returns the position of the \c nth captured text in the search
string. 

\endlist


\section2 String

A \Class String is a sequence of zero or more Unicode characters.
\QS's \Class String class uses the \QT QString class's functions and
syntax.

Strings can be created and concatenated as follows.

\code
    var text = "this is a";
    var another = new String( "text" );
    var concat = text + " " + another;  // concat == "this is a text"
\endcode

\section3 String Properties

\list 

\o length : Number; The length property specifies the length of the
string.

\endlist 

\section3 Static String Functions

\list 

\o fromCharCode ( static function )

\code
    var s = String.fromCharCode( 65, 66, 67, 68 );
    System.println( s ); // prints "ABCD"
\endcode

Returns a string made up of the characters with code \c code1, \c
code2, etc, according to their Unicode character codes.

\endlist

\section3 String Functions

\list

\o charAt( pos : Number ) : String; Returns the character in the
string at position \c pos. If the position is out of bounds, \c
undefined is returned.

\o charCodeAt( pos : Number ) : Number; Returns the character code of
the character at position \c pos in the string. If the position is out
of bounds, \c undefined is returned.

\o indexOf( pattern : String or RegExp, pos : Number ) : Number;
Returns the index of \c pattern in the string, starting at position \c
pos. If no position is specified, the function starts at the beginning
of the string. If the pattern is not found in the string, -1 is
returned.

\o lastIndexOf( pattern : String or RegExp, pos : Number ) : Number;
Returns the last index of \c pattern in the string, starting at
position \c pos and searching backwards from there. If no position is
specified, the function starts at the end of the string. If the
pattern is not found in the string, -1 is returned.

\o match( pattern : RegExp ) : String; Returns the matched
pattern if this string matches the pattern defined by \c regexp. If \c
regexp is not a valid regular expression, \c undefined is returned.

\o search( pattern : String or RegExp ) : String; same as find.

\o searchRev( pattern : String or RegExp ) : String; same as findRev.

\o replace( pattern : RegExp, newValue : String ) : String; Replaces
the first occurrence of \c pattern in the string with \c newvalue if
the pattern is found in the string. A modified copy of string is
returned.

If \c pattern is a regular expression with global set, all occurances
of \c pattern in the string will be replaced.

\o split( pattern : String or RegExp ) : String[]; Returns an array of
strings containing this string split on each occurrence of \c
pattern.

\o substring( startIndex : Number, endIndex : Number ) : String;
Returns a copy of this string which is the substring starting at \c
startIndex and ending at \c endIndex.

\o toLowerCase() : String; Returns a lowercase copy of this string.

\o lower() : String; Same as toLowerCase().

\o toUpperCase() : String; Returns an uppercase copy of this string.

\o upper() : String; Same as toUpperCase().

\o isEmpty() : Boolean; Returns true if the string is empty, i.e. has
a length of 0; otherwise returns false.

\o left( length : Number ) : String; Returns a substring containing
the \c length leftmost characters of this string.

\o right( length : Number ) : String; Returns a substring containing
the \c length rightmost characters of this string.

\o mid( start : Number, length : Number ) : String; Returns a copy of
this string which is the substring starting a \c start and is \c
length characters long.

\o find( pattern : String or RegExp, pos : Number ) : Number; Returns
the first position of \c pattern after \c pos. If the pattern is not
found, -1 is returned.  If \c pos is not specified, position 0 is
used.

\o findRev( pattern : Number, pos : Number ) : String; Returns the
first position of \c pattern before or at \c pos, searching backward. If
pattern is not found, -1 is returned. If \c pos is not specified, the
search starts at the end of the string.

\o startsWith( pattern : String or RegExp ) : Boolean; Returns true if
the string starts with \c pattern; otherwise returns false.

\o endsWith( pattern : String or RegExp ) : Boolean; Returns true if
the string ends with \c pattern; otherwise returns false.

\o arg( value : String or Number, fieldWidth : Number ) : String; This
function will return a string that replaces the lowest numbered
occurrence of %1, %2, ..., %9 with \c value.

The \c fieldWidth parameter specifies the minimum amount of space that
\c value is padded to. A positive \c fieldWidth will produce
right-aligned text, whereas a negative \c fieldWidth will produce
left-aligned text.

\o argInt( value : Number, fieldWidth : Number, base : Number ) :
String; This function behaves like arg above, but is specialized for
the case where \c value is an integer.

\c value is expressed in base \c base, which is 10 by default and must
be between 2 and 36.

\o argDec( value : Number, fieldWidth : Number, format : Number,
precision : Number ) : String; This function behaves like \c arg() above,
but is specialized for the case where \c value is a decimal value.

Argument \c value is formatted according to the \c format specified,
which is 'g' by default and can be any of the following:

\list
\o \c e - format as [-]9.9e[+|-]999
\o \c E - format as [-]9.9E[+|-]999
\o \c f - format as [-]9.9
\o \c g - use \c e or \c f format, whichever is the most concise
\o \c G - use \c E or \c f format, whichever is the most concise
\endlist

With 'e', 'E', and 'f', \c precision is the number of digits after the
decimal point. With 'g' and 'G', \c precision is the maximum number of
significant digits (trailing zeroes are omitted).

\endlist

\section2 Color

The \Class Color class is used to represent colors. Instances of
\Class Color can be passed to C++ slots that take arguments of type
QColor.

\section3 Color Properties

\list 

\o red : Number; The red component of the color. This is a value between 0 and
255.

\o green : Number; The green component of the color. This value is between 0
and 255.

\o blue : Number; The blue component of the color. This value is between 0 and
255.

\o name : String; The name of the color, if a matching name for the
color exists; otherwise an empty string.

\o rgb : Number; The rgb color code of the color. The color code is a bitmask
of the form \c 0xRRGGBB, where RR is the red component, GG is the
green component, and BB is the blue component expressed as hexadecimal
digits.

\o hue : Number; The color's hue, as defined by the HSV color model.

\o saturation : Number; The color's saturation, as defined by the HSV color
model.

\o value : Number; The colors's value, as defined by the HSV color model.

\endlist

\section3 Color Functions

\list

\o setRgb( colorcode ); Sets the color code of the color. The value is
a bitmask on the form 0xRRGGBB, where RR=red, GG=green, and BB=blue,
all as hexadecimal digits.

\o setRgb( red, green, blue ); Sets the red, green and blue color values
of the color to \c red, \c green and \c blue.

\o light() : Color; Returns a Color that is a lighter version of this
one.

\o dark() : Color; Returns a Color that is a darker version of this
one.

\endlist

\section2 Palette

The \Class Palette class contains color groups for each widget state.
A palette consists of three color groups: active, disabled, and
inactive. All widgets contain a palette, and all widgets in Qt use
their palette to draw themselves. This makes the user interface easily
configurable and easier to keep consistent.

\section3 Palette Properties

\list

\o active : ColorGroup; The active color group is used for the window
that has the keyboard focus.

\o inactive : ColorGroup; The inactive color group is used for the
other windows.

\o disabled : ColorGroup; The disabled color group is used for widgets
(not windows) that are disabled.

\endlist


\section2 ColorGroup

The \Class QColorGroup class contains a group of widget colors. 

\section3 ColorGroup Properties

\list

\o background : Color; General background color.

\o foreground : Color; General foreground color.

\o base : Color; Used as background color for text entry widgets, for
example; usually white or another light color.

\o text : Color; The foreground color used with \c base.

\o button : Color; General button background color.

\o buttonText : Color; A foreground color used with the \c button
color.

\o light : Color; Used for 3D bevel and shadow effects. Lighter than
\c button color.

\o midlight : Color; Used for 3D bevel and shadow effects. Between \c
button and \c light.

\o dark : Color; Used for 3D bevel and shadow effects. Darker than \c
button.

\o mid : Color; Used for 3D bevel and shadow effects. Betwen \c button
and \c dark.

\o shadow : Color; Used for 3D bevel and shadow effects. A very dark
color.

\o highlight : Color; A color to indicate a selected item or the
current item.

\o highlightedText : Color; A text color that contrasts with \c
highlight.

\endlist

\section2 ByteArray

The \Class ByteArray class is an array optimized for storing raw
bytes. Instances of \Class ByteArray can be passed to C++ slots
that take arguments of type QByteArray.

\section3 ByteArray Properties

\list

\o length : Number; The number of bytes in the byte array. This value
is read-only.

\o size : Number; The number of bytes in the byte array. This value is
read-only.

\endlist

\section3 ByteArray Functions

\list

\o charAt( index : Number ) : String; Returns the character (byte) at
the position index in the byte array. The byte is returned as a
string.

\endlist

\section2 Font

The \Class Font class represents a font. Instances of \Class Font can
be passed to C++ slots that take arguments of type QFont.

\section3 Font Properties

\list 

\o family : String; The fonts family or name, such as \c SansSerif.

\o pointSize : Number; The point size of the font. A point is 1/72
inch. Using point size will give you a fixed sized independent of the
device the font is used on. For instance, a screen has different
resolution than a printer.

\o pixelSize : Number; The pixel size of the font. The size of a pixel
is determined by the device the font is used for. For instance, a
printer may have a resolution of have 600 pixels/inch, whereas a
monitor may only achieve 120 pixels/inch.

\o bold : Boolean; True if the font is bold; otherwise false.

\o italic : Boolean; True if the font is italic; otherwise false.

\o underline : Boolean; True if the font is underline; otherwise
false.

\o strikeout : Boolean; True if the strikeout is on; otherwise false.

\endlist

\section2 Pixmap

The \Class Pixmap class can be used to represent images in QSA.
Instances of \Class Pixmap can be passed to C++ slots that take
arguments of type QPixmap.

The \Class Pixmap constructor can take a filename referring to an image that
will then be loaded:

\code 
var background = new Pixmap( "background.png" );
\endcode

\section3 Pixmap Properties

\list

\o width : Number; The width of the pixmap. This value is read-only.

\o height : Number; The height of the pixmap. This value is read-only.

\o rect : Rect; The enclosing rectangle (0, 0, width, height) of the
pixmap. This value is read-only.

\o size : Size; The size of the rectangle. This value is read-only.

\o depth : Number; The color depth of the pixmap. The pixmap depth is
also called bits per pixel (bpp) or bit planes of a pixmap. A null
pixmap has depth 0. This value is read-only.

\endlist

\section3 Pixmap Functions

\list 

\o isNull() : Boolean; Returns true if this is a null pixmap;
otherwise returns false. A null pixmap has zero width, zero depth, and
no contents.

\o fill( color ); Fills the pixmap with the specified color.

\o resize( size : Size ); Resizes the pixmap to the specified
size.

\o resize( width : Number, height : Number ); Resizes the pixmap to
the specified dimensions.

\o load( fileName : String ); Loads the pixmap data from the specified
file.

\o save( fileName : String ); Saves the pixmap to the specified
file.

\endlist

\section1 Built-in Objects

The built-in \c Math object provides functions that include: \c abs(),
\c acos() and \c cos(), \c asin() and \c sin(), \c atan(), \c atan2()
and \c tan(), \c ceil(), \c floor() and \c round(), \c exp() and \c
log(), \c max() and \c min(), \c pow() and \c sqrt(), \c random(), and
\c round().

The built-in \c System object provides functions including: \c
getenv(), \c setenv(), \c print() and \c println().

\section2 Math

The \Class Math object always exists in a \QS program. Use the \Class
Math object to access mathematical constants and functions, e.g.
\code
    with ( Math ) {
	var x = PI * 2;
	var angle = 1.3;
	var y = x * sin( angle );
    }
\endcode
The \Class Math object supports all the common mathematical functions,
for example: \c abs(), \c acos() and \c cos(), \c asin() and \c sin(),
\c atan(), \c atan2() and \c tan(), \c ceil(), \c floor() and \c
round(), \c exp() and \c log(), \c max() and \c min(), \c pow() and \c
sqrt(), \c random(), and \c round().

See also, \l{+ operator}, \l{++ operator}, \l{- operator}, \l{--
operator}, \l{* operator}, \l{/ operator}, \l{% operator}, \l{-=
operator}, \l{+= operator}, \l{*= operator}, \l{/= operator} and \l{%=
operator}.

\section3 Math Properties

All the \Class Math properties are read-only constants.

\list
\o E -- Eulers constant. The base for natural logarithms.
\o LN2 -- Natural logarithm of 2.
\o LN10 -- Natural logarithm of 10.
\o LOG2E -- Base 2 logarithm of E.
\o LOG10E -- Base 10 logarithm of E.
\o PI -- Pi.
\o SQRT1_2 -- Square root of 1/2.
\o SQRT2 -- Square root of 2.
\endlist

\section3 Math Functions

\list

\o abs( number : Number ) : Number;

Returns the absolute value of the given \c number. The equivalent of

\code
    x = x < 0 ? -x : x;
\endcode

\code
    var x = -99;
    var y = 99;
    with ( Math ) {
	x = abs( x );
	y = abs( y );
    }
    if ( x == y ) System.println( "equal" );
\endcode

\o acos( number : Number ) : Number; Returns the arccosine of the
given \c number in radians between 0 and \c Math.PI. If the number is
out of range, returns \l NaN.

\o asin( number : Number ) : Number; Returns the arcsine of the given
\c number in radians between \c{-Math.PI/2} and \c{Math.PI/2}. If the
number is out of range, returns \l NaN.

\o atan( number : Number ) : Number; Returns the arctangent of the
given \c number in radians between \c{-Math.PI/2} and
\c{Math.PI/2}. If the number is out of range, returns \l NaN.

\o atan2( yCoord : Number, xCoord : Number ) : Number; Returns the
counter-clockwise angle in radians between the positive x-axis and the
point at (\c xCoord, \c yCoord). The value returned is always between
\c{-Math.PI} and \c{Math.PI}.

Example:
\code
    function polar( x, y )
    {
	return Math.atan2( y, x );
    }
\endcode

\o ceil( number : Number ) : Number; If the \c number is an integer,
it returns the \c number. If the \c number is a floating point value,
it returns the smallest integer greater than the \c number.

Example:
\code
    var x = 913.41;
    x = Math.ceil( x ); // x == 914
    var y = -33.97;
    y = Math.ceil( y ); // y == -33
\endcode

\o cos( number : Number ) : Number; Returns the cosine of the given \c
number. The value will be in the range -1..1.

\o exp( number : Number ) : Number; Returns \c{Math.E} raised to the
power of the given \c number.

\o floor( number : Number ) : Number; If the \c number is an integer,
it returns the \c number. If the \c number is a floating point value,
it returns the greatest integer less than the \c number.

\o log( number : Number ) : Number; If the \c number is \> 0, it
returns the natural logarithm of the given \c number. If the \c number
is 0, it returns \c Infinity. If the \c number is \< 0, it returns \l
NaN.

\o max( number1 : Number, number2 : Number ) : Number; Returns the
largest of \c number1 and \c number2.

\o min( number1 : Number, number2 : Number ) : Number; Returns the
smallest of \c number1 and \c number2.

\o pow( number : Number, power : Number ) : Number; Returns the value
of the \c number raised to the \c power.

\o random() : Number; Returns a pseudo-random floating point number
between 0 and 1. Pseudo random numbers are not truly random, but may
be adequate for some applications, for example, games and simple
simulations.

\o round( number : Number ) : Number; Returns the \c number rounded to
the nearest integer. If the fractional part of the \c number is \>=
0.5, the \c number is rounded up; otherwise it is rounded down.

\o sin( number : Number ) : Number; Returns the sine of the given \c
number. The value will be in the range -1..1.

\o sqrt( number : Number ) : Number; If the \c number is \>= 0, it
returns the square root. If the \c number is \< 0, it returns \l NaN.

\o tan( number : Number ) : Number; Returns the tangent of the given
\c number.

\endlist 


\section2 System

The \Class System object always exists in a \QS program. Use the
\Class System object to access and manipulate environment variables,
e.g. with \c getenv() and \c setenv(), and to print text to the
console with \c print() and \c println().

\section3 System Functions

\list

\o getenv( environmentVariable : String ) : String; Returns the string
stored in the given \c environmentVariable.

Example:
\code
    var q = System.getenv( "QTDIR" ); // q == "/usr/local/qt"
\endcode

\o print( expression : String ); Prints the \c expression (applying
\Func toString() if necessary) to the console (\c stdout).

\o println( expression : String ); Prints the \c expression (applying
\Func toString() if necessary) to the console (\c stdout), followed by
a newline.

\o setenv( environmentVariable : String, value : String ); Sets the \c
environmentVariable to the \c value. If the \c environmentVariable
does not exist it is created. The environment is only changed within
the context of the \QS process for the duration of the process.

\endlist
