use function keyword through out the code

use function keyword through out the code

From man zsh:
-----------------------------------------------------------------------
Note also the unhelpful interaction of  aliases  and  function  defini‐
tions:

	alias func='noglob func'
	func() {
	    echo Do something with $*
	}

Because  aliases  are expanded in function definitions, this causes the
following command to be executed:

	noglob func() {
	    echo Do something with $*
	}

which defines noglob as well as func as functions with the body  given.
To  avoid this, either quote the name func or use the alternative func‐
tion definition form `function func'.
-----------------------------------------------------------------------

Therefore make use of the function keyword through out the code for
defining shell functions. Also harmonize its usage, where it is used allready.