invoke bash functions in xargs

As xargs could MapReduce multiple lines of input into segregated input, Recently I keen to use it to tackle with many situation that need to use a bash loop.
But I find I could not pass parameters to xargs if I want to invoke functions in it.
This may happen if you need functional programming, but xargs could hardly achieve it at a glance.
You can not invoke functions that defined in same file with xargs command because after retrieving the $PATH, xargs could not got this function.
What you need to do is to register this function, or just export -f it.

# !/bin/bash

# define a function
function tackle()
{
    echo $1
}

# export function: tackle
export -f tackle

# use bash -c to execute function: tackle
xargs -a b -I{}  bash -c "tackle {}"

Just as comments explains in script, use export -f to export a bash function.
Then use bash -c functionName to invoke this function in xargs.
I reckon it will be much popular and hacky to use xargs in the future.
Hard to imagine how the ancient UNIX engineers figure out it! It is fabulous!