Shell Programming and Scripting

Hi all.
I have a selection of awk functions which I have written and tested in a main awk program.
From the command line I use nawk -f function -f main to run main and call my functions from within it.
I now wish to use these awk function again but want to call them from inside an awk section of a shell script. I am wondering whether this is possible and if so how i might go about it.

Code:

myfuntion(data){
some data validation
returns 0 or 1
}

Code:

#!/bin/sh
cat somefile.csv| nawk ' 
valid=myfunction(data)

Thanks for your help ppl

Something like this seems to work, at least with mawk on Ubuntu.

Code:

mawk -f func.awk -f - somefile.csv <<'HERE'
valid=myfunction(data)
HERE

As noted elsewhere, awk doesn't need to have data piped into it by cat, and indeed, in this case, it wouldn't work, since the script is supplied as standard input, not the data.