Macro vtkio::call_numeric_buffer_fn

macro_rules! call_numeric_buffer_fn {
    ($ fn : ident :: < _, $ ($ params : ident), * >
 ($ data : expr, $ ($ args : expr), *) or $ err : block) => { ... };
    ($ fn : ident :: < _ > ($ ($ args : expr), *) or $ err : block) => { ... };
    ($ fn : ident :: < _, $ ($ params : ident), * > ($ data : expr) or $ err :
 block) => { ... };
    ($ data : ident . $ fn : ident :: < _, $ ($ params : ident), * >
 ($ ($ args : expr), *) or $ err : block) => { ... };
    ($ data : ident . $ fn : ident :: < _ > ($ ($ args : expr), *) or $ err :
 block) => { ... };
}

Applies $fn to an DataBuffer mapping valid numeric data types by corresponding generic parameters. For example, passing an DataBuffer containing data of type u8 will cause this macro to call $fn with type parameter u8 like $fn::<u8>(buffer).

Examples

// Implement pretty printing of a `DataBuffer` derivative for numeric buffers.
struct MyBuffer(DataBuffer);
impl fmt::Display for MyBuffer {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        unsafe fn display_buf<T: Any + fmt::Display>(buf: &DataBuffer, f: &mut fmt::Formatter) {
            for item in buf.iter::<T>().unwrap() {
                write!(f, "{} ", item)
                    .expect("Error occurred while writing MyBuffer.");
            }
        }
        call_numeric_buffer_fn!( display_buf::<_>(&self.0, f) or {});
        write!(f, "")
    }
}