AWK Curry Function - Can a function return a function? - gawk

Question

I'm working on an AWK script that quite a big mess at the moment, and I'm trying to improve it (primarily because I want to improve my Awk scripting skillz)
I realize that there isn't a way to do Object Oriented Programming within Awk or Gawk, but is there a way to at least curry functions? As in returning a function from within a function? (Not return the result of the executed function, but rather return a function that can be executed)
I found a Stack Overflow post, where #GreenFox showed that its possible to execute a function with the name of the function stored in a variable. The example he posted is below:
function foo(s){print "Called foo "s}
function bar(s){print "Called bar "s}
{
var = "";
if(today_i_feel_like_calling_foo){
var = "foo";
}else{
var = "bar";
}
#var( "arg" ); # This calls function foo(), or function bar() with "arg"
}
What I'm wondering is if its possible to return a function from another function.
For example, a function that accepts a string that can be used in awks printf as a format, and returns a function that accepts two other arguments, and essentially executes printf( fmt_from_parent_func, sub_func_arg1, sub_func_arg2 ).
Here's my attempt at trying to accomplish the following:
#! /usr/local/bin/awk -f
function setFmt ( fmt ){
function _print ( var, val ){
printf ( fmt ? fmt : "%-15s: %s\n" ), str1, str2
}
return #_print
}
BEGIN {
fmtA = setFmt("%-5s: %s\n")
#fmtA("ONE","TWO")
}
Which results in the errors:
awk: ./curry.awk:4: function _print ( var, val ){
awk: ./curry.awk:4: ^ syntax error
awk: ./curry.awk:4: function _print ( var, val ){
awk: ./curry.awk:4: ^ syntax error
awk: ./curry.awk:6: printf ( fmt ? fmt : "%-15s: %s\n" ), str1, str2
awk: ./curry.awk:6: ^ unexpected newline or end of string
awk: ./curry.awk:11: fmtA = setFmt("%-5s: %s\n")
awk: ./curry.awk:11: ^ unexpected newline or end of string
awk: ./curry.awk:12: #fmtA("ONE","TWO")
awk: ./curry.awk:12: ^ unexpected newline or end of string
If anyone knows if this is at all possible (which Im starting to see myself), and knows a way to accomplish something to this effect.. that would be awesome.
Thanks!

Answer 1

With GNU awk you can return the name of a function as a string from another function but you can't declare a function within another function nor can you return a function (or an array) in any awk - all you can return from a function in awk is a scalar value (i.e. a number or string).
Is this what you're trying to do:
$ cat tst.awk
function _print ( var, val ){
printf _print_fmt, var, val
}
function setFmt ( fmt ){
_print_fmt = (fmt ? fmt : "%-15s: %s\n" )
return "_print"
}
BEGIN {
fmtA = setFmt("%-5s: %s\n")
#fmtA("ONE","TWO")
}
$ awk -f tst.awk
ONE : TWO