Reuse value in snippet

Question

I recently switched to using neovim + deoplete + neosnippets and I'm trying to get a snippet to do a thing that I'm pretty sure that I've been able to do in UltiSnips. In a template I'd like to be able to enter a value for ${0:THING} and have it be reused throughout the snippet output without retyping it. I'm not sure if there's a point in providing the snippet because it doesn't do what I want, but just in case my description isn't clear enough, this:

snippet thing
abbr    thing
    #ifndef THING_${0:TYPE}_H
    #define THING_${0}_H

    #include <something.h>

    BEGIN_DECLS

    // ...

    END_DECLS

    #endif /* THING_${0}_H */

would produce:

#ifndef THING_TEST_H
#define THING_TEST_H

#include <something.h>

BEGIN_DECLS

// ...

END_DECLS

#endif /* THING_TEST_H */

if I hit <C-k> and enter 'TEST' when prompted.

Answer 1

The answer is synchronized placeholders; I just couldn't find anything online/in the manual because I didn't know the terminology. The correct snippet would be:

snippet thing
abbr    thing
    #ifndef THING_${1:something}_H
    #define THING_$1_H

    #include <something.h>

    BEGIN_DECLS

    // ...

    END_DECLS

    #endif /* THING_$1_H */

For some reason, starting from 0 creates an error.