AW: AW: SIP translate Union

[Marian Thomsen]

Thank you very much, the last example helped me a lot!

I feel like I'm asking too much, but if you have some time I'm  stuck translating an (anonymos) union inside a struct. The anonymity does not seem to be the problem (I tested by naming it), but the location inside the struct. Another aproach was to use the existing struct as a wrapper, but I couldn't get it to work.

Here I tried by wrapping it inside a struct, but get the error message: 'field 'u' has incomplete type 'mu'.

test_union.h

struct myType{

    enum {CHAR, INT, DOUBLE} tag;
    union{                        // tested naming it 'mu', no difference
        /* tag = CHAR */
        char char_value;
        /* tag = INT */
        int int_value;
        /* tag = DOUBLE */
        double double_value;
    }u;
    void print_my_type() const;
};


The SIP file:


struct myType{

%TypeHeaderCode
#include <test_union.h>
%End

    enum tag {CHAR, INT, DOUBLE};

    struct mu_wrapper /PyName=mu/
    {

    %TypeHeaderCode
    #include <test_union.h>

    struct mu_wrapper
    {
        union mu u;
    };
    %End

        /* tag = CHAR */
        char char_value {
        %GetCode
            sipPy = PyUnicode_FromString(&(sipCpp->u.char_value));
        %End
        %SetCode
            if (PyUnicode_Check(sipPy))
                sipCpp->u.char_value;
            else
                sipErr = 1;
        %End
        };

        /* tag = INT */
        int int_value {
        %GetCode
            sipPy = PyLong_FromLong(sipCpp->u.int_value);
        %End
        %SetCode
            if (PyLong_Check(sipPy))
                sipCpp->u.int_value;
            else
                sipErr = 1;
        %End
        };

        /* tag = DOUBLE */
        double double_value {
        %GetCode
            sipPy = PyFloat_FromDouble(sipCpp->u.double_value);
        %End
        %SetCode
            if (PyFloat_Check(sipPy))
                sipCpp->u.double_value;
            else
                sipErr = 1;
        %End
        };
    };

    void print_my_type() const;
};


Thank you for your help!

M.T.

________________________________
Von: Phil Thompson <phil at riverbankcomputing.com>
Gesendet: Freitag, 27. November 2020 11:52
An: Marian Thomsen <marian.th at outlook.de>
Cc: pyqt at riverbankcomputing.com <pyqt at riverbankcomputing.com>
Betreff: Re: AW: SIP translate Union

On 26/11/2020 08:08, Marian Thomsen wrote:
> Thank you for the advice!
>
> Unfortunately I cant get a simple example to work.
> I have a simple union in the header test_union.h
>
>
> union {
>     int test1;
>     int test2;
> } u;
>
> And this is the best I got so far in the .sip file:
>
>
> struct union{
>
> %TypeHeaderCode
> #include <test_union.h>
> %End
>
>     int *test1 {
>     %GetCode
>         sipPy = PyLong_FromLongLong(sipCpp->test1)
>         if(sipPy == NULL)
>             sipPy = NULL;
>     %End
>     %SetCode
>         if (PyLong_Check(sipPy))
>             sipCpp->test1;
>         else
>             sipErr = 1;
>     %End
>     };
>     int *test2 {
>     %GetCode
>         sipPy = PyLong_FromLongLong(sipCpp->test2);
>         if(sipPy == NULL)
>             sipPy = NULL;
>     %End
>     %SetCode
>         if (PyLong_Check(sipPy))
>             sipCpp->test2;
>         else
>             sipErr = 1;
>     %End
>     };
> }u;
>
> I get a syntax error in the last line and have tried to write it so
> that sip would understand it, but also with something like:
>
>
> typedef struct union union;
> union u{ ... };
>
> I got no luck so far. Am I completly wrong?
>
> Some advice would be appreciated

First of all, the contents of your test_union.h file is the definition
of a variable, not a type. It should be...

union u {
     int test1;
     int test2;
};

At the moment you can't wrap a union directly. You have to wrap it in a
struct and pretend to Python that the struct is the union. Also there is
a bug in the C code generator which generates invalid code (but the
equivalent C++ code is Ok). So try something like the following...

struct u_wrapper /PyName=u/
{
%TypeHeaderCode
#include<test_union.h>

struct u_wrapper
{
     union u wrapped;
};
%End

     int test1 {
     %GetCode
         sipPy = PyLong_FromLongLong(sipCpp->wrapped.test1);
     %End
     %SetCode
         if (PyLong_Check(sipPy))
             sipCpp->wrapped.test1;
         else
             sipErr = 1;
     %End
     };
};

Phil
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