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digitalmars.D.learn - Input timeout

reply "Josh" <moonburntm gmail.com> writes:
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
May 13 2013
next sibling parent reply =?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:
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
May 13 2013
parent reply "Josh" <moonburntm gmail.com> writes:
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?
May 13 2013
parent =?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:
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
May 13 2013
prev sibling parent "Adam D. Ruppe" <destructionator gmail.com> writes:
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.
May 14 2013