std/env

Environment variables and command-line arguments. Import with import "std/env";.

get works on the native backend and Node. args, set, and unset are native only.

Functions

get

string? get(name: string)

Returns the value of the environment variable name, or none if it is not set.

let home = env.get("HOME");
if (home != none) {
    io.print(home!);
}

set

bool set(name: string, v: string)

Defines or overwrites the environment variable name for this process and its children. Returns true on success.

unset

bool unset(name: string)

Removes the environment variable name. Returns true on success.

env.set("MODE", "debug");
env.get("MODE");            # "debug"
env.unset("MODE");
env.get("MODE");            # none

args

[string] args()

Returns the command-line arguments. args()[0] is the program itself, so real arguments start at index 1.

import "std/env";
import "std/io";

int main() {
    let argv = env.args();
    if (argv.len() < 2) {
        io.print("usage: greet <name>");
        return 1;
    }
    io.print("Hello, " + argv[1]);
    return 0;
}