diff options
| -rwxr-xr-x | vala.html.markdown | 37 |
1 files changed, 19 insertions, 18 deletions
diff --git a/vala.html.markdown b/vala.html.markdown index 4072f3b3..a0fbc5c1 100755 --- a/vala.html.markdown +++ b/vala.html.markdown @@ -7,7 +7,7 @@ filename: LearnVala.vala In GNOME's own words, "Vala is a programming language that aims to bring modern programming language features to GNOME developers without imposing any additional runtime requirements and without using a different ABI compared to applications and libraries written in C." -Vala has aspects of Java and C#, so it'll be natural to those who know either or. +Vala has aspects of Java and C#, so it'll be natural to those who know either. [Read more here.](https://wiki.gnome.org/Projects/Vala) @@ -24,8 +24,6 @@ Comment */ /* Data Types */ -// Vala supports the data types supported by most other programming languages. - char character = 'a' unichar unicode_character = 'u' // 32-bit unicode character @@ -40,10 +38,10 @@ ushort m; string text = "Hello,"; // Note that the == operator will check string content string verbatim = """This is a verbatim (a.k.a. raw) string. Special characters -(e.g. \n) are not interpreted. They may also be multiple lines long."""; +(e.g. \n and "") are not interpreted. They may also be multiple lines long."""; // String Templates allow for easy string formatting -string string_template = @"$text world"; // "$text" evaluates to "Hello" +string string_template = @"$text world"; // "$text" evaluates to "Hello," int test = 5; int test2 = 10; @@ -54,8 +52,8 @@ string template_slice = string_template[7:12]; // => "world" // Most data types have methods for parsing. bool parse_bool = bool.parse("false"); // => false -int parse_int = int.parse("-52"); -string parse_string = parse_int.to_string(); +int parse_int = int.parse("-52"); // => -52 +string parse_string = parse_int.to_string(); // => "-52" /* Basic I/O */ @@ -67,7 +65,7 @@ stderr.printf("Error message"); // Error printing /* Arrays */ int[] int_array = new int[10]; // Array of ints with 10 slots -int better_int_array[10]; // Shorter way of making int array with 10 slots +int better_int_array[10]; // Above expression, shortened int_array.length; // => 10; int[] int_array2 = {5, 10, 15, 20}; // Can be created on-the-fly @@ -80,7 +78,7 @@ unowned int[] array_slice_ref = int_array2[1:3]; // Reference to data int[,] multi_array = new int[6,4]; // 6 is the number of arrays, 4 is their size int[,] multi_array2 = {{7, 4, 6, 4}, {3, 2, 4, 6}, - {5, 9, 5, 1}}; + {5, 9, 5, 1}}; // new int[3,4] multi_array2[2,3] = 12; // 2 is the array, 3 is the index in the array int first_d = multi_array2.length[0] // => 3 int second_d = multi_array2.length[1] // => 4 @@ -97,12 +95,12 @@ add_to_array.resize(20); // Array now has 20 slots uint8[] chars = "test message".data; chars.move(5, 0, 7); -print ((string) chars); // Casts the array to a string and prints "message" +stdout.printf((string) chars); // Casts the array to a string and prints it /* Control Flow */ -var a = 1; -var b = 2; +int a = 1; +int b = 2; int[] foreach_demo = {2, 4, 6, 8}; while (b > a) { // While loop; checks if expression is true before executing @@ -147,7 +145,7 @@ int cast_to_float = 10; float casted_float = (float) cast_to_float; // static casting; no runtime checks // For runtime checks, use dynamic casting. -// Dynamically casted objects must meet the following: +// Dynamically casted objects must be the following: // - Object's class is the same class as the desired type // - Object's class is a subclass of the desired type // - Desired class is an interface implemented by the object's class @@ -158,8 +156,6 @@ var inferred_string = "hello"; // Type inference /* Methods (a.k.a. functions) */ -// Vala methods are C functions, and are bound by the same rules. - int method_demo(string arg1, Object arg2) { // Returns int and takes args return 1; } @@ -173,12 +169,17 @@ void some_method(int number) { } // Won't compile void some_better_method(string text, int number = 0) { } +some_better_method("text"); +some_better_method("text", 12); + // varargs (variable-length argument lists) are also supported. void method_with_varargs(int arg1, ...) { var varargs_list = va_list(); // gets the varargs list + string arg_string = varargs_list.arg(); // gets arguments, one after another int int_vararg = varargs_list.arg(); + stdout.printf("%s, %d\n", arg_string, int_vararg) } @@ -200,7 +201,7 @@ void final_delegate_demo() { call_delegate(delegate_match); // Passes matching method as argument } -// Lambdas/Anonymous Methods are defined with "=>" +// Lambdas (a.k.a. Anonymous Methods) are defined with "=>" (a) => { stdout.printf("%d\n", a); } // Prints "a" @@ -235,13 +236,13 @@ enum HouseSize { // An example of an enum BIG } - /* Classes and Object-Oriented Programming */ class Message : GLib.Object { // Class Message extends GLib's Object private string sender; // a private field public string text {get; set;} // a public property - internal bool sent = false; // internal (classes in same package) field + protected bool is_digital = true; // protected (this class and subclasses) + internal bool sent = false; // internal (classes in same package) public void send(string message_sender) { // public method sender = message_sender; |