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Kavachकवच

Standard Library: std.devices

● Intermediate5 min

Every type, method and function of std.devices: what the spec lists, then each declaration in its source, with its examples and the line that declares it.

Spec 14.18 · learn it in Devices.

A declaration below shows what a program writes against: a type's fields, a function's parameters, what it gives, its contracts (require, ensure) and its examples. kavach test runs every example, so each one is true of the code.

spec 14.18 · std.devicesthe examples, tested

What the spec lists

Function or methodGives
devices.serial_ports() -> [String]The serial ports there are: COM3 on Windows, /dev/ttyUSB0 on Linux
devices.open_serial(path, baud) -> SerialPort ! DeviceErrorOpens the port at path at baud bits a second (8 data bits, no parity, 1 stop bit)
port.write(data) ! DeviceErrorSends the Bytes data
port.read(max) -> Bytes ! DeviceErrorUp to max bytes: what has arrived, waiting at most a second for the first; empty Bytes when none came
port.close()Closes the port; a port is closed anyway when its last holder ends

std.devices · devices.kav

use std.devices: 2 types and 1 function. stdlib/devices/devices.kav

DeviceError type

Why a device couldn't be opened, read or written.

pub type DeviceError = NotFound(path: String) | Denied(path: String) | Failed(path: String, reason: String)

SerialPort type

An open serial port.

pub type SerialPort {
    pub path: String
    id: Int
}

write method

Sends data.

pub fn write(self, data: Bytes) ! DeviceError uses Serial

read method

Up to max bytes: what has arrived, waiting at most a second for the first. Empty when none came.

pub fn read(self, max: Int) -> Bytes ! DeviceError uses Serial

close method

Closes the port.

pub fn close(self) uses Serial

open_serial function

Opens the serial port at path (COM3, /dev/ttyUSB0) at baud bits a second, 8 data bits, no parity, 1 stop bit.

pub fn open_serial(path: String, baud: Int) -> SerialPort ! DeviceError uses Serial