[Scilab-Dev] Redirecting input and output streams

[Antoine ELIAS]

Hello Sylvain,

You can get Scilab outputs by setting your own output function.

void scilab_print(const char *text)
{
     std::cout << text << std::endl;
}

//redirect output to your own function:
setScilabOutputMethod(&scilab_print);

Commands send to call_scilab by SendScilabJob are muted ( execstr("cmd", 
"errcatch"); ), so to show outputs you need to explicitly call "disp" 
function in your code or
use another mechanism to put your commands directly in queue of 
execution by using StoreConsoleCommand function.

See attached file as example.
Have a good weekend.
Antoine
Le 02/03/2019 à 00:41, SylvainCorlay a écrit :
> Hello everyone,
>
> This is my first post on this mailing list. I hope that I am not breaking
> any rule!
>
> I am interested in embedding the scilab interpreter in a C++ application.
> The `call_scilab` API appears to be the wayt to go for simple code
> execution, however I wonder it is possible to capture / redirect output
> streams? The motivation is to create a kernel for Jupyter. I am aware of the
> existing pexpect-based kernel but I would like to create a new kernel that
> would be running in-process and not rely on piping to capture textual
> output.
>
> Note: this is something that we have already done for other languages.
> /xeus-cling/ is a  C++ kernel
> <https://blog.jupyter.org/interactive-workflows-for-c-with-jupyter-fe9b54227d92>
> based on the cling C++ interpreter from CERN. /xeus-python/ is an
> alternative Python kernel. Both are based on the xeus C++ implementation of
> the Jupyter protocol, support auto-complete, quick help, rich output
> display, interactive widgets.
>
> I would like to know how far we could go with the `call_scilab` API with
> respect to redirection, and whether there would be some means to access
> lower-level control on the interpreter (for e.g. inspection, auto-complete
> requests, getting a handle on the last value returned).
>
> Looking forward to hearing from you, although I will be travelling in the
> next few days.
>
> Best,
>
>
>
> --
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-------------- next part --------------
#include <iostream>
#include <exception>
#include <stdio.h> /* stderr */
#include <windows.h> /* stderr */

#include "call_scilab.h"
#include "scilabWrite.hxx" /**/

// Filename: simple_call_scilab.c

extern "C"
{
    int StoreConsoleCommand(const char *command, int iWaitFor);
}

const char LAUNCHER_VERSION[] = "1.0";

#define SENDSCILABJOB(x) \
    if(SendScilabJob(x) != 0) { \
        fprintf(stderr, "Failed to execute \"%s\" command\n", x); \
        return 0; \
        }

void scilab_print(const char *text)
{
    std::cout << text << std::endl;
}

int main()
{
    try
    {
        if (StartScilab(NULL, NULL, NULL) == FALSE)
        {
            fprintf(stderr, "Error while calling StartScilab\n");
            return -1;
        }
    }
    catch (std::exception e)
    {
        fprintf(stderr, "oops: %s\n", e.what());
    }

    //redirect output to your own function:
    setScilabOutputMethod(&scilab_print);

    /*change mode to output only outputs*/
    //SENDSCILABJOB((char*)"mode(2);");

    StoreConsoleCommand("1+1", 1);

    SENDSCILABJOB((char*)"__a__ = 1+1;disp(__a__);");

    StoreConsoleCommand("rand(3, 3)", 1);

    SENDSCILABJOB((char*)"__a__ = rand(3, 3);disp(__a__);");

    if (TerminateScilab(NULL) == FALSE)
    {
        fprintf(stderr, "Error while calling TerminateScilab\n");
        return -2;
    }
    return 0;
}