CODEWITHSUNDEEP
cif-statementmacrosgotoc89
Imobilis
Imobilis

Reputation: 1489

goto label trick in a macro for condition

There was one evil macro trick I DON'T REMEMBER and it was a lot like this:

public :
var = 3;
}

Which should expand to

if(route == ROOTING_PUBLIC)
{
    var = 3;
}

How can I achieve something like this ?

Upvotes: 1

Views: 595

Answers (2)

Imobilis
Imobilis

Reputation: 1489

Now that I found the implementation of such bad idea, I also could understand the deeper sense in it.

The code

#define public if(route == ROOTING_PUBLIC) { public_offset

The usage

public :
    var = 3;
} // <-- makes no sense

The idea

To avoid loops, to reduce the spaghetti code and to demonstrate more exotic code. It will be better to be implemented with an id system as such:

#define public(id) if(route == ROOTING_PUBLIC) { public_##id

And then if the user decides to loop the code (that by semantics will be invoked solely "publicly"):

public(2) :
    var = 3;
    if(var > 3) goto public_2; // or #define repeat(x, id) goto x##_##id
}

Even better version of it will include the omitting of magic numbers, replacing it with user_id

Upvotes: 1

Thomas Dickey
Thomas Dickey

Reputation: 54505

Macros are used to reduce clutter; though a lot of clutter indicates problems with the program structure.

The OP's notion of the possible macro does not match C-syntax. But something along those lines might be:

#define if_ROOTED(name) if (ROOTED_##name & input) { output = e##name; }

#define ROOTED_FIRST 16
#define ROOTED_SECOND 64

#define eFIRST 1
#define eSECOND 2

    if_ROOTED(FIRST);
    if_ROOTED(SECOND);

where input and output and the repetitive test are the "clutter" to be eliminated. Making a table would be a better way to reduce clutter; however OP asked for a hint about macros.

Upvotes: 3

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