`std/io`

The three streams every process is started with. They are ordinary Source and Sink values (docs/design/STREAMS.md), so everything that reads a file reads standard input, and everything that writes a file writes to the screen:

const total = lines().count().await()?
standardOutput().addLine("{total} lines").await()?

print/printError of the prelude and readLine() here stay as the short form for the common case: a program that prints a line does not want to think about a stream.

Modules

std/io/libThe three streams every process is started with.

Everything

fn linesThe lines of standard input, as a stream: the same stage File.lines uses, over the same kind of source.
fn readLineThe next line of standard input without its line break: Ok(None) at the end of the input, and an IoError for a line whose bytes are not UTF-8.
fn standardErrorStandard error, unbuffered for the reason it is everywhere: a diagnostic that is lost is worse than a slow one.
fn standardInputStandard input as a stream of byte chunks, each read on a thread of the blocking pool as it arrives.
fn standardOutputStandard output as a stream of byte chunks.