9.2.5 Functions and Their Effect on Variable Typing

awk is a very fluid language. It is possible that awk can't tell if an identifier represents a regular variable or an array until runtime. Here is an annotated sample program:

function foo(a) { a[1] = 1 # parameter is an array } BEGIN { b = 1 foo(b) # invalid: fatal type mismatch foo(x) # x uninitialized, becomes an array dynamically x = 1 # now not allowed, runtime error }

Usually, such things aren't a big issue, but it's worth being aware of them.