Bounded stream reads

Read a bounded number of characters with read(count). The count is Unicode characters, not UTF-8 bytes. Zero consumes nothing; a negative count reads to EOF.

def demo() -> Result[(), IoError]:
    write_text("bounded.txt", "é🦀hello")?
    with open("bounded.txt")? as file:
        print(file.read(2)?)?
        print(file.read()?)?
    Ok(())
def main() -> Result[(), IoError]:
    demo()?
    Ok(())

é🦀
hello

readline(count) limits a line read in the same way. A long line can arrive in several pieces; a negative count reads the rest of the line.

def demo() -> Result[(), IoError]:
    write_text("lines.txt", "abcd\nnext")?
    with open("lines.txt")? as file:
        print(file.readline(2)?)?
        print(file.readline(2)?)?
        print(file.readline(2)? == "\n")?
    Ok(())
def main() -> Result[(), IoError]:
    demo()?
    Ok(())

ab
cd
True