Standard Input

Brendan Hansen

// Use the necessary core libraries
use core.io { Reader }
use core.conv

// Use the printf function that lives in the core package.
// This cannot be `use core.printf`, because that will look
// for a package called `printf` in `core`.
use core {
    printf, stdio
}

main :: () {
    // Create a io.Reader over the stdio.stream to be able scan
    // the input in parts. Also, defer freeing the reader until
    // the end of `main`.
    stdin_reader := Reader.make(&stdio.stream)
    defer Reader.free(&stdin_reader)

    // Read a single line of input.
    line := stdin_reader->read_line()

    // Split the line on the first space.
    a_str, b_str := line->bisect(" ")

    // Parse and convert both parts to i32s, with a default value
    // of 0 if it fails to parse as an i32.
    a_value := conv.parse(i32, a_str)->value_or(0)
    b_value := conv.parse(i32, b_str)->value_or(0)

    // Compute our result.
    result := a_value + b_value

    // Output our result using formatted printing.
    printf("{} + {} = {}\n", a_value, b_value, result)
}