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System

Overview

System object is a very basic object including primitive methods in the overall of Kinx system.

Action Methods

Here are methods to act something.

Method Content
System.abort() Abort the program.
System.halt() Halt the program.
System.exec(cmd) Execute the cmd on shell via system().
System.gc() Force GC.
System.localtime(unixtime) Returns a JSON structured object of a localtime.
System.mktime(tmobject) Returns a unixtime from a JSON structured object.
System.print(...) Prints it out without a new line at the tail.
System.println(...) Prints it out with a new line at the tail.
System.sleep(ms) Sleep the program with ms milliseconds.
System.try(func){.else(alt)/.retry(times,ms)}* See this section for details.

Checking Methods

Here are methods to check something.

Method Content
System.exepath() The path of this executable.
System.kinxpath() The path of the Kinx executable.
System.getPlatform() The string of this system such as architecture, an operating system, and so on.
System.isUtf8Bytes(code/str) Check if the code is utf8 code, or if the head of char of str is utf8 code.

Definition Methods

Here are methods to define something.

Method Content
System.defineException(name) Defines your own exception. See defineException for details.

Details

JSON Structured Object

Here is the object shape.

{
    year:   year,
    month:  month,
    day:    day,
    hour:   hour,
    minute: minute,
    second: second,
}

How To Use System.try

System.try is used to handle an exception, and if an exception occurs, it is used to return a value to be alternative. Here is a basic usage.

var x = System.try({ => getData() }).else(null);

In this case, x will be null if getData raised an exception. As to pass nothing to .else means that .else returns null, you can write .else() instead of .else(null).

var x = System.try({ => getData() }).else(null);

If you want to retry the getData() function, you can write it such as following example.

var x = System.try({ => getData() }).retry(2, 100).else(null);

.retry method has 2 arguments. The first argument is the number of retry, and the second argument is an interval between retries in milliseconds.

Examples

Methods of System is often used in many examples. This section will show some examples which is not used other examples.

Example 1. Abort

Code

for (n in 1..100) {
    System.println(n);
    if (n == 10) System.abort();
}

Result

1
2
3
4
5
6
7
8
9
10
This program aborted.

Example 2. Halt

Code

for (n in 1..20) {
    System.println(n);
    if (n == 10) System.halt();
}

Result

1
2
3
4
5
6
7
8
9
10

Example 3. Sleep

Code

var tmr = new SystemTimer();
System.sleep(500);      // waiting 500 milliseconds.
if (tmr.elapsed() > 0.4) {
    System.println("Successful");
}

Result

Successful

Example 4. System.try()

Code

var n = 0;
function test1() {
    if (++n == 5) {
        return "Successful";
    }
    throw RuntimeException("Error");
}

var x;
x = System.try({ => test1() }).else(1000);
System.println(x);
x = System.try({ => test1() }).retry(2, 50).else(500);
System.println(x);
x = System.try({ => test1() }).retry(10, 50).else(300);
System.println(x);

Result

1000
500
Successful