User defined function issue in awk - bash

Question

My code 1 :
awk -F'|' -v PARM_VAL="${PARM_VALUE[*]}" '
BEGIN { split(PARM_VAL,pa," ")
fn_1()
{
print "inside fn"
}
}
FNR==NR{ for(i=1;i<=NF;i++) a[NR,i]=$i; }
{if (FILENAME == "SPP_OUT") {print $1}}
fn_1
END {printf " second value of SPPIN : "a[2,2]} ' SPP_IN SPP_OUT
I am getting error fatal: function `fn_1' not defined
My code 2 :
awk -F'|' -v PARM_VAL="${PARM_VALUE[*]}" '
BEGIN { split(PARM_VAL,pa," ")
fn_1()
{
ret = "returned"
return ret
}
}
FNR==NR{ for(i=1;i<=NF;i++) a[NR,i]=$i; }
{if (FILENAME == "SPP_OUT") {print $1}}
m=fn_1()
END {printf " second value of SPPIN : "a[2,2];print $m} ' SPP_IN SPP_OUT
I am facing
awk: cmd. line:6: return ret
awk: cmd. line:6: ^ `return' used outside function context
Can any asssist ?
Thanks

Answer 1

The function should be defined out of the BEGIN block. For example:
$ cat function.awk
function fib(n, n_1, n_2)
{
if (n < 2) {
return n
} else {
n_1 = fib(n - 1)
n_2 = fib(n - 2)
return n_1 + n_2
}
}
BEGIN {
for (i = 0; i < 5; ++i) {
printf("fib(%d) = %d\n", i, fib(i));
}
}
$ awk -f function.awk
fib(0) = 0
fib(1) = 1
fib(2) = 1
fib(3) = 2
fib(4) = 3
$
The user-defined awk function syntax is
function NAME(PARAMETER-LIST)
{
BODY-OF-FUNCTION
}
The tricky part is:
PARAMETER-LIST is a list of the function's arguments and local variable
names, separated by commas. When the function is called, the argument
names are used to hold the argument values given in the call. The
local variables are initialized to the empty string. A function cannot
have two parameters with the same name, nor may it have a parameter
with the same name as the function itself.
See the awk manual for more details.

Answer 2

To get the nucleus of your code working I had to add the function keyword when defining the function, and parentheses when making the call like so:
$ cat foo.awk
BEGIN { print "begin" }
function fn_1()
{
print "inside fn"
}
{
fn_1()
}
END { print "end" }
$ echo 'xyz' | awk -f foo.awk
begin
inside fn
end
From the awk manual:
The definition of a function named name looks like this:
function name(parameter-list)
{
body-of-function
}