15分钟学会Haxe3

一个老外用代码+注释写的Haxe语法快速参考，虽说可能没有15分钟学会那么夸张，不过还是很有参考意义的。这里先把地址贴上，以后等这文档稳定了，翻译一下。

https://github.com/jdonaldson/learnxinyminutes-docs/blob/master/haxe.html.markdown

 

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language: haxe filename: LearnHaxe3.hx contributors:

- ["Justin Donaldson", "https://github.com/jdonaldson/"]

Haxe is a web-oriented language that provides platform support for C++, C#, Swf/ActionScript, Javascript, Java, and Neko byte code (also written by the Haxe author). Note that this guide is for Haxe version 3. Some of the guide may be applicable to older versions, but it is recommended to use other references.

/*   Welcome to Learn Haxe 3 in 15 minutes.  http://www.haxe.org   This is an executable tutorial.  You can compile and run it using the haxe   compiler, while in the same directory as LearnHaxe.hx:   haxe -main LearnHaxe3 -x out */// Let's start with comments... this is a single line comment/*   And this is multiline. Multiline comments are also used to generate   javadoc-style documentation for haxedoc.  They will be used if they precede   a class, class function, or class variable. *//*   This is your first actual haxe code, it's declaring an empty package.  A   package isn't necessary, but it's useful if you want to create a namespace   for your code (e.g. org.module.ClassName). */package; // empty package, no namespace./*   if you import code from other files, it must be declared before the rest of   the code. */import haxe.ds.ArraySort;// you can import many classes/modules at once with "*"import haxe.ds.*;/*   you can also import classes in a special way, enabling them to extend the   functionality of other classes.  More on 'using' later. */using StringTools;/*   Typedefs are like variables... for types.  They must be declared before any   code.  More on this later. */typedef FooString = String;// Typedefs can also use "structural" types, more on that later as well!typedef FooObject = { foo: String };class LearnHaxe3{    /*       If you want certain code to run automatically, you need to put it in       a static main function, and specify the class in the compiler arguments.       In this case, we've specified the "LearnHaxe3" class in the compiler       arguments above.     */    static function main(){        /*           Trace is the default method of printing haxe expressions to the           screen.  Different targets will have different methods of           accomplishing this.  E.g., java, c++, c#, etc. will print to std           out.  Javascript will print to console.log, and flash will print to           an embedded TextField.  All traces come with a default newline.           Finally, It's possible to prevent traces from showing by using the           "--no-traces" argument on the compiler.         */        trace("Hello World, with trace()!");        /*           Trace can handle any type of value or object.  It will try to print           a representation of the expression as best it can.  You can also           concatenate strings with the "+" operator:         */        trace(            " Integer: " + 10 +            " Float: " + 3.14 +            " Boolean: " + true            );        /*           Remember what I said about expressions needing semicolons? You           can put more than one expression on a line if you want.         */        trace('two expressions..'); trace('one line');        //////////////////////////////////////////////////////////////////        // Types & Variables        //////////////////////////////////////////////////////////////////        trace("***Types & Variables***");        /*           You can save values and references to data structures using the           "var" keyword:         */        var an_integer:Int = 1;        trace(an_integer + " is the value for an_integer");        /*           Haxe is statically typed, so "an_integer" is declared to have an           "Int" type, and the rest of the expression assigns the value "1" to           it.  It's not necessary to declare the type in many cases.  Here,           the haxe compiler is inferring that the type of another_integer           should be "Int".         */        var another_integer = 2;        trace(another_integer + " is the value for another_integer");        // The $type() method prints the type that the compiler assigns:        $type(another_integer);        // You can also represent integers with hexadecimal:        var hex_integer = 0xffffff;        /*           Haxe uses platform precision for Int and Float sizes.  It also           uses the platform behavior for overflow.           (Other numeric types and behavior are possible using special           libraries)         */        /*           In addition to simple values like Integers, Floats, and Booleans,           Haxe provides standard library implementations for common data           structures like strings, arrays, lists, and maps:         */        var a_string = "some" + 'string';  // strings can have double or single quotes        trace(a_string + " is the value for a_string");        var x = 1;        var an_interpolated_string = 'the value of x is $x';        /*           Strings are immutable, instance methods will return a copy of           parts or all of the string.           (See also the StringBuf class).         */        var a_sub_string = a_string.substr(0,4);        trace(a_sub_string + " is the value for a_sub_string");        /*           Arrays are zero-indexed, dynamic, and mutable.  Missing values are           defined as null.         */        var a = new Array<String>(); // an array that contains Strings        a[0] = 'foo';        trace(a.length + " is the value for a.length");        a[9] = 'bar';        trace(a.length + " is the value for a.length (after modification)");        trace(a[3] + " is the value for a[3]"); //null        /*           Arrays are *generic*, so you can indicate which values they contain           with a type parameter:         */        var a2 = new Array<Int>(); // an array of Ints        var a3 = new Array<Array<String>>(); // an Array of Arrays (of Strings).        /*           Maps are simple key/value data structures.  The key and the value           can be of any type.         */        var m = new Map<String, Int>();  // The keys are strings, the values are Ints.        m.set('foo', 4);        // You can also use array notation;        m['bar'] = 5;        trace(m.exists('bar') + " is the value for m.exists('bar')");        trace(m.get('bar') + " is the value for m.get('bar')");        trace(m['bar'] + " is the value for m['bar']");        var m2 =  ['foo' => 4, 'baz' => 6]; // Alternative map syntax        trace(m2 + " is the value for m2");        /*           Remember, you can use type inference.  The Haxe compiler will           decide the type of the variable the first time you pass an           argument that sets a type parameter.         */        var m3 = new Map();        m3.set(6, 'baz'); // m3 is now a Map<Int,String>        trace(m3 + " is the value for m3");        /*           Haxe has many more common datastructures in the haxe.ds module, such as           List, Stack, and BalancedTree         */        //////////////////////////////////////////////////////////////////        // Operators        //////////////////////////////////////////////////////////////////        trace("***OPERATORS***");        // basic arithmetic        trace((4 + 3) + " is the value for (4 + 3)");        trace((5 - 1) + " is the value for (5 - 1)");        trace((2 * 4) + " is the value for (2 * 4)");        trace((8 / 4) + " is the value for (8 / 3) (division always produces Floats)");        trace((12 % 4) + " is the value for (12 % 4)");        //basic comparison        trace((3 == 2) + " is the value for 3 == 2");        trace((3 != 2) + " is the value for 3 != 2");        trace((3 >  2) + " is the value for 3 > 2");        trace((3 <  2) + " is the value for 3 < 2");        trace((3 >= 2) + " is the value for 3 >= 2");        trace((3 <= 2) + " is the value for 3 <= 2");        //bitwise operators        /*        ~       Unary bitwise complement        <<      Signed left shift        >>      Signed right shift        >>>     Unsigned right shift        &       Bitwise AND        ^       Bitwise exclusive OR        |       Bitwise inclusive OR        */        //increments        var i = 0;        trace("Increments and decrements");        trace(i++); //i = 1. Post-Incrementation        trace(++i); //i = 2. Pre-Incrementation        trace(i--); //i = 1. Post-Decrementation        trace(--i); //i = 0. Pre-Decrementation        //////////////////////////////////////////////////////////////////        // Control Structures        //////////////////////////////////////////////////////////////////        trace("***CONTROL STRUCTURES***");        // if statements        var j = 10;        if (j == 10){            trace("this is printed");        } else if (j > 10){            trace("not greater than 10, so not printed");        } else {            trace("also not printed.");        }        // there is also a "ternary" if:        (j == 10) ?  trace("equals 10") : trace("not equals 10");        /*           Finally, there is another form of control structures that operates           at compile time:  conditional compilation.         */#if neko        trace('hello from neko');#elseif js        trace('hello from js');#else        trace('hello from another platform!');#end        /*           The compiled code will change depending on the platform target.           Since we're compiling for neko (-x or -neko), we only get the neko           greeting.         */        trace("Looping and Iteration");        // while loop        var k = 0;        while(k < 100){            // trace(counter); // will print out numbers 0-99            k++;        }        // do-while loop        var  l = 0;        do{            trace("do statement always runs at least once");        } while (i > 0);        // for loop        /*           There is no c-style for loop in Haxe, because they are prone           to error, and not necessary.  Instead, Haxe has a much simpler           and safer version that uses Iterators (more on those later).         */        var m = [1,2,3];        for (val in m){            trace(val + " is the value for val in the m array");        }        // Note that you can iterate on an index using a range        // (more on ranges later as well)        var n = ['foo', 'bar', 'baz'];        for (val in 0...n.length){            trace(val + " is the value for val (an index for m)");        }        trace("Array Comprehensions");        // Array comprehensions give you the ability to iterate over arrays        // while also creating filters and modifications.        var filtered_n = [for (val in n) if (val != "foo") val];        trace(filtered_n + " is the value for filtered_n");        var modified_n = [for (val in n) val += '!'];        trace(modified_n + " is the value for modified_n");        var filtered_and_modified_n = [for (val in n) if (val != "foo") val += "!"];        trace(filtered_and_modified_n + " is the value for filtered_and_modified_n");        //////////////////////////////////////////////////////////////////        // Switch Statements (Value Type)        //////////////////////////////////////////////////////////////////        trace("***SWITCH STATEMENTS (VALUE TYPES)***");        /*           Switch statements in Haxe are very powerful.  In addition to working           on basic values like strings and ints, they can also work on the           generalized algebraic data types in enums (more on enums later).           Here's some basic value examples for now:         */        var my_dog_name = "fido";        var favorite_thing  = "";        switch(my_dog_name){            case "fido" : favorite_thing = "bone";            case "rex"  : favorite_thing = "shoe";            case "spot" : favorite_thing = "tennis ball";            default     : favorite_thing = "some unknown treat";            // case _   : "some unknown treat"; // same as default        }        // The "_" case above is a "wildcard" value        // that will match anything.        trace("My dog's name is" + my_dog_name                + ", and his favorite thing is a: "                + favorite_thing);        //////////////////////////////////////////////////////////////////        // Expression Statements        //////////////////////////////////////////////////////////////////        trace("***EXPRESSION STATEMENTS***");        /*           Haxe control statements are very powerful because every statement           is also an expression, consider:        */        // if statements        var k = if (true){            10;        } else {            20;        }        trace("K equals ", k); // outputs 10        var other_favorite_thing = switch(my_dog_name) {            case "fido" : "teddy";            case "rex"  : "stick";            case "spot" : "football";            default     : "some unknown treat";        }        trace("My dog's name is" + my_dog_name                + ", and his other favorite thing is a: "                + other_favorite_thing);        //////////////////////////////////////////////////////////////////        // Converting Value Types        //////////////////////////////////////////////////////////////////        trace("***CONVERTING VALUE TYPES***");        // You can convert strings to ints fairly easily.        // string to integer        Std.parseInt("0"); // returns 0        Std.parseFloat("0.4"); // returns 0.4;        // integer to string        Std.string(0); // returns "0";        // concatenation with strings will auto-convert to string.        0 + "";  // returns "0";        true + ""; // returns "true";        // See documentation for parsing in Std for more details.        //////////////////////////////////////////////////////////////////        // Dealing with Types        //////////////////////////////////////////////////////////////////        /*           As mentioned before, Haxe is a statically typed language.  All in           all, static typing is a wonderful thing.  It enables           autocompletions, and can be used to check the correctness of a           program in very thorough ways.  Plus, the Haxe compiler is super fast.           You probably won't be waiting on it very much.           *HOWEVER*, there are times when you just wish the compiler would let           something slide, and not throw a type error in a limited case.           To do this, Haxe has two separate keywords.  The first is the            "Dynamic" type:         */        var dyn: Dynamic = "any type of variable, such as this string";        /*           All that you know for certain with a Dynamic variable is that the            compiler will no longer worry about what type it is. It is like a            wildcard variable:  You can pass it instead of any variable type,           and you can assign any variable type you want.            The other more extreme option is the "untyped" keyword         */            untyped {                var x:Int = 'foo';                var y:String = 4;            }        /*           The untyped keyword operates on entire *blocks* of code, skipping            any type checks that might be otherwise required. This keyword should           be used very sparingly, such as in limited conditionally-compiled           situations where type checking is a hinderance.           In general, skipping type checks is *not* recommended.  Use the            enum, inheritance, or structural type models in order to verify the           correctness of your program.  Only when you're certain that none of           the type models work should you resort to "Dynamic" or "untyped".         */        //////////////////////////////////////////////////////////////////        // Basic Object Oriented Programming        //////////////////////////////////////////////////////////////////        trace("***BASIC OBJECT ORIENTED PROGRAMMING***");        /*           Create an instance of FooClass.  The classes for this are at the           end of the file.         */        var instance = new FooClass(3);        // read the public variable normally        trace(instance.public_any + " is the value for instance.public_any");        // we can read this variable        trace(instance.public_read + " is the value for instance.public_read");        // but not write it        // instance.public_write = 4; // this will throw an error if uncommented:        // trace(instance.public_write); // as will this.        trace(instance + " is the value for instance"); // calls the toString method        trace(instance.toString() + " is the value for instance.toString()"); // same thing        /*           Instance has the "FooClass" type, while acceptBaseFoo has the           BaseFooClass type.  However, since FooClass extends BaseFooClass,           it is accepted.         */        BaseFooClass.acceptBaseFoo(instance);        /*           The classes below have some more advanced examples, the "example()"           method will just run them here.         */        SimpleEnumTest.example();        ComplexEnumTest.example();        TypedefsAndStructuralTypes.example();        UsingExample.example();    }}/*   This is the "child class" of the main LearnHaxe3 Class */class FooClass extends BaseFooClass implements BaseFooInterface{    public var public_any:Int; // public variables are accessible anywhere    public var public_read (default,null): Int; // use this style to only enable public read    public var public_write (null, default): Int; // or public write    public var property (get, set): Int; // use this style to enable getters/setters    // private variables are not available outside the class.    // see @:allow for ways around this.    var _private:Int; // variables are private if they are not marked public    // a public constructor    public function new(arg:Int){        super(); // call the constructor of the parent object, since we extended BaseFooClass        this.public_any= 0;        this._private = arg;    }    // getter for _private    function get_property() : Int {        return _private;    }    // setter for _private    function set_property(val:Int) : Int {        _private = val;        return val;    }    // special function that is called whenever an instance is cast to a string.    public function toString(){        return _private + " with toString() method!";    }    // this class needs to have this function defined, since it implements    // the BaseFooInterface interface.    public function baseFunction(x: Int) : String{        // convert the int to string automatically        return x + " was passed into baseFunction!";    }}/*    A simple class to extend*/class BaseFooClass {    var base_variable:Int;    public function new(){        base_variable = 4;    }    public static function acceptBaseFoo(b:BaseFooClass){    }}/*    A simple interface to implement*/interface BaseFooInterface{    public function baseFunction(x:Int):String;}//////////////////////////////////////////////////////////////////// Enums and Switch Statements///////////////////////////////////////////////////////////////////*   Enums in Haxe are very powerful.  In their simplest form, enums   are a type with a limited number of states: */enum SimpleEnum {    Foo;    Bar;    Baz;}//   Here's a class that uses it:class SimpleEnumTest{    public static function example(){        var e_explicit:SimpleEnum = SimpleEnum.Foo; // you can specify the "full" name        var e = Foo; // but inference will work as well.        switch(e){            case Foo: trace("e was Foo");            case Bar: trace("e was Bar");            case Baz: trace("e was Baz"); // comment this line to throw an error.        }        /*           This doesn't seem so different from simple value switches on strings.           However, if we don't include *all* of the states, the compiler will           complain.  You can try it by commenting out a line above.           You can also specify a default for enum switches as well:         */        switch(e){            case Foo: trace("e was Foo again");            default : trace("default works here too");        }    }}/*    Enums go much further than simple states, we can also enumerate    *constructors*, but we'll need a more complex enum example */enum ComplexEnum{    IntEnum(i:Int);    MultiEnum(i:Int, j:String, k:Float);    SimpleEnumEnum(s:SimpleEnum);    ComplexEnumEnum(c:ComplexEnum);}// Note: The enum above can include *other* enums as well, including itself!class ComplexEnumTest{    public static function example(){        var e1:ComplexEnum = IntEnum(4); // specifying the enum parameter        /*           Now we can switch on the enum, as well as extract any parameters           it might of had.         */        switch(e1){            case IntEnum(x) : trace('$x was the parameter passed to e1');            default: trace("Shouldn't be printed");        }        // another parameter here that is itself an enum... an enum enum?        var e2 = SimpleEnumEnum(Foo);        switch(e2){            case SimpleEnumEnum(s): trace('$s was the parameter passed to e2');            default: trace("Shouldn't be printed");        }        // enums all the way down        var e3 = ComplexEnumEnum(ComplexEnumEnum(MultiEnum(4, 'hi', 4.3)));        switch(e3){            // You can look for certain nested enums by specifying them explicitly:            case ComplexEnumEnum(ComplexEnumEnum(MultiEnum(i,j,k))) : {                trace('$i, $j, and $k were passed into this nested monster');            }            default: trace("Shouldn't be printed");        }        /*           Check out "generalized algebraic data types" (GADT) for more details           on why these are so great.         */    }}class TypedefsAndStructuralTypes {    public static function example(){        // Here we're going to use typedef types, instead of base types.        var t1:FooString = "some string";        /*           We can use typedefs for "structural types".  These types are defined           by their field structure, not by class inheritance.  Here's an           anonymous object with a String field named "foo":         */        var fooObj = { foo: 'hi' };        /*           Remember back at the top where we declared the FooObj typedef?           Since fooObj matches that structure, we can use it anywhere that           a "FooObject" is expected.         */        var f = function(fo:FooObject){            trace('$fo was passed in to this function');        }        f(fooObj); // call the FooObject signature function with fooObj.        /*           Note that typedefs can have optional fields as well, marked with "?"           typedef OptionalFooObj = {                ?optionalString: String,                requiredInt: Int           }         */        /*           Typedefs work well with conditional compilation.  For instance,           we could have included this at the top of the file:#if( js )        typedef Surface = js.html.CanvasRenderingContext2D;#elseif( nme )        typedef Surface = nme.display.Graphics;#elseif( !flash9 )        typedef Surface = flash8.MovieClip;#elseif( java )        typedef Surface = java.awt.geom.GeneralPath;#end        That would give us a single "Surface" type to work with across        all of those platforms.        */    }}class UsingExample {    public static function example() {        /*           The "using" import keyword is a special type of class import that           alters the behavior of any static methods in the class.           In this file, we've applied "using" to "StringTools", which contains           a number of static methods for dealing with String types.         */        trace(StringTools.endsWith("foobar", "bar") + " should be true!");        /*           With a "using" import, the first argument type is extended with the           method.  What does that mean?  Well, since "endsWith" has a first           argument type of "String", that means all String types now have the           "endsWith" method:         */        trace("foobar".endsWith("bar") + " should be true!");        /*           This technique enables a good deal of expression for certain types,           while limiting the scope of modifications to a single file.           Note that the String instance is *not* modified in the run time.           The newly attached method is not really part of the attached           instance, and the compiler still generates code equivalent to a           static method.         */      }}

We're still only scratching the surface here of what Haxe can do. For a formal overiew of all Haxe features, checkout the online manual, the online api, and "haxelib", the haxe library repo.

For more advanced topics, consider checking out:

• Abstract types
• Macros, and Compiler Macros
• Tips and Tricks

Finally, please join us on the mailing list, on IRC #haxe on freenode, or on Google+.