[R] Single character input without Enter

[Henrik Bengtsson]

Thanks.

If you could wrap it up in a package, provide an Rd help page with an
example, and make it available on for instance CRAN, that would be
even better. Then one day maybe someone else contribute with a unix
version etc.  Make sure to credit your sources and get the licenses
right.

/Henrik

On Wed, Feb 24, 2010 at 8:56 AM, Dieter Menne
<dieter.menne at menne-biomed.de> wrote:
>
>
> Dieter Menne wrote:
>>
>> How do I wait for a single character input without terminating "Enter"?
>>
>
>
> In case someone needs a solution for Windows, here it is. Compiled Dll from
>
> http://www.menne-biomed.de/download/keystate.zip
>
> Dieter
>
> #dyn.unload("keystate.dll")
> dyn.load("keystate.dll")
>
> AsyncKeyState = function(vkey){
>  state = 0
>  .C("AsyncKeyState",as.integer(state),as.integer(vkey))[[1]]
> }
>
> ShiftKeyState = function(){
>  state = 0
>  .C("ShiftKeyState",as.integer(state))[[1]]
> }
>
> ControlKeyState = function(){
>  state = 0
>  .C("ControlKeyState",as.integer(state))[[1]]
> }
>
> PressedKey = function(){
>  state = 0
>  .C("PressedKey",as.integer(state))[[1]]
> }
>
>
> # while(TRUE){
> #   Sys.sleep(1)
> #   cat(PressedKey(),"\n")
> #}
>
> // C Program
> #include <windows.h>
> #include <R.h>
> //#include <Rdefines.h>
> //#include <R_ext/Error.h>
>
> #define DLLIMPORT __declspec (dllexport)
> #define VK_A 0x41
> #define VK_Z 0x5A
>
> DLLIMPORT void AsyncKeyState(int *state,int* vKey) {
>   state[0] = GetAsyncKeyState(*vKey) <0;
> }
>
> DLLIMPORT void ControlKeyState(int *state) {
>   state[0] = GetAsyncKeyState(VK_CONTROL) <0;
> }
>
> DLLIMPORT void ShiftKeyState(int *state) {
>  state[0] = GetAsyncKeyState(VK_SHIFT) < 0 ;
> }
>
> DLLIMPORT void PressedKey(int *state) {
>  byte keyState[256];
>  GetKeyboardState(keyState);
>  for (*state=VK_A; (*state) <= VK_Z; (*state)++)
>    if (keyState[*state] & 0x80)
>        return ;
>  *state = 0;
> }
>
>
> --
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>
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