Is there a way in D to only accept input for a certain time, instead of std.stdio.readln's behaviour? Something like "Press a key in 3 seconds to abort".

Thanks

Josh

On 05/13/2013 08:50 PM, Josh wrote:
> Is there a way in D to only accept input for a certain time, instead of
> std.stdio.readln's behaviour? Something like "Press a key in 3 seconds
> to abort".
>
> Thanks
>
> Josh

An unlikely solution is std.concurrency because it already has a timeout facility:

import std.stdio;
import std.concurrency;
import std.datetime;
import std.string;

void lineReader(Tid owner)
{
    while (true) {
        string line = readln().chomp();
        owner.send(line);
    }
}

void main()
{
    spawn(&lineReader, thisTid);

    while (true) {
        auto received =
            receiveTimeout(3.seconds,
                           (string line) {
                               writefln("Thanks for -->%s<--", line);
                           });

        if (!received) {
            writeln("Patiently waiting...");
        }
    }
}

Ali

On Tuesday, 14 May 2013 at 04:14:27 UTC, Ali Çehreli wrote:
> On 05/13/2013 08:50 PM, Josh wrote:
>> Is there a way in D to only accept input for a certain time, instead of
>> std.stdio.readln's behaviour? Something like "Press a key in 3 seconds
>> to abort".
>>
>> Thanks
>>
>> Josh
>
> An unlikely solution is std.concurrency because it already has a timeout facility:
>
> import std.stdio;
> import std.concurrency;
> import std.datetime;
> import std.string;
>
> void lineReader(Tid owner)
> {
>     while (true) {
>         string line = readln().chomp();
>         owner.send(line);
>     }
> }
>
> void main()
> {
>     spawn(&lineReader, thisTid);
>
>     while (true) {
>         auto received =
>             receiveTimeout(3.seconds,
>                            (string line) {
>                                writefln("Thanks for -->%s<--", line);
>                            });
>
>         if (!received) {
>             writeln("Patiently waiting...");
>         }
>     }
> }
>
> Ali

Thanks Ali, that's almost what I need. Your answer requires the user to press enter to send the line. Would it be possible to have getch-like behaviour without using C, or would that be the only way?

On 05/13/2013 09:22 PM, Josh wrote:

> Your answer requires the user to
> press enter to send the line. Would it be possible to have getch-like
> behaviour without using C, or would that be the only way?

I don't know how to set stdin to non-blocking mode in D.

However, if you are sure that stdin is tied to the keyboard (as opposed to e.g. redirected from a file), you can use terminal IO on unix systems:

  http://forum.dlang.org/thread/im8cnf$ioe$1@digitalmars.com?page=1

Ali

On Tuesday, 14 May 2013 at 03:50:22 UTC, Josh wrote:
> Is there a way in D to only accept input for a certain time, instead of std.stdio.readln's behaviour? Something like "Press a key in 3 seconds to abort".

see also this thread:
http://forum.dlang.org/thread/vavskrvzebozkreubnbh@forum.dlang.org

the terminal.d file can do it like this:
https://github.com/robik/ConsoleD/blob/master/terminal.d


import terminal;

void main() {
        auto terminal = Terminal(ConsoleOutputType.linear);
        // ConsoleInputFlags.raw means get one character at a time instead of   one line at a time
        auto input = RealTimeConsoleInput(&terminal, ConsoleInputFlags.raw);

        // this is in milliseconds, returns true if they actually pressed the   key
        if(input.timedCheckForInput(3_000)) {
                // input was available
                terminal.writeln("Aborted!");
                auto ch = input.getch();
                terminal.writeln("btw you said ", ch);
        } else {
               // timer expired
                terminal.writeln("proceeding with operation");
        }
}



It should work on windows and linux though I haven't personally tested this example on windows yet.