Pausable Loops

pausable.jl

# TODO: Need different behavior for the REPL
function set_stdin_mode!(raw::Bool)
    res = ccall(
        :jl_tty_set_mode,
        Int32,
        (Ptr{Void}, Int32),
        STDIN.handle,
        int32(raw)
    )
    return res != -1
end

function has_input()
    start_reading(STDIN)
    Base.process_events(false)
    stop_reading(STDIN)
    return nb_available(STDIN) > 0
end

get_input() = readavailable(STDIN)

# Mutate state over body of a early-terminated loop
x = 0

set_stdin_mode!(true)
for i in 1:100
    # Original body of loop
    println(i)
    x -= 1
    sleep(0.1)

    # Pause logic
    abort_signal = false
    if has_input() && get_input() == "p"
        @printf("Press 'c' to continue.\n")
        @printf("Press 'a' to abort.\n")
        while true
            if has_input()
                input = get_input()
                if input == "c"
                    break
                elseif input == "a"
                    abort_signal = true
                    break
                end
            end
        end
    end
    if abort_signal
        break
    end
end
set_stdin_mode!(false)

println(x)