Sys

The sys module provides information and control of the feral interpreter

All the given examples assume the following imports:

let sys = import('std/sys');
let io = import('std/io');

Functions

• var_exists
• exit

Variables

• args
• install_prefix
• self_bin
• self_base

var_exists

sys.var_exists(name: str) -> bool

Checks if the given variable name in known to the virtual machine

Example:

io.println(sys.var_exists('hello'));
let hello = 'Hello, world!';
io.println(sys.var_exists('hello'));

Gives the output:

false
true

exit

sys.exit(code: int = 0) -> nil

Exits the program using the given return code. A return code of zero (default value) indicates a graceful exit while a non-zero value indicates a failure in running the program

Example:

let success = true;
if success {
    sys.exit();
}
else {
    sys.exit(-1);
}

args

sys.args: vector<string>

Contains the arguments passed to feral, after the main source file

Example (args.fer):

io.println(sys.args);

Possible output:

$ feral args.fer 1 2 3
[1, 2, 3]
$ feral args.fer hello world
[hello, world]

self_bin

sys.self_bin: string

Contains the full path of the interpreter, according to binary's location

Example (loc.fer):

io.println(sys.self_bin);

self_base

sys.self_base: string

Contains the base directory of the interpreter, according to binary's location

Example (loc.fer):

io.println(sys.self_base);

Possible output:

$ /usr/local/bin/feral loc.fer
/usr/local
$ feral loc.fer
feral

install_prefix

sys.install_prefix: string

Contains the path to the feral installation directory

Example:

io.println(sys.install_prefix);

Possible output:

/usr/local