How to test if a string contains more than N nested function calls?

January 21, 2022

There is a set of strings that represents a list of nested function calls:

# (string, number of nested calls)
tests = [('f1(p1)', 0), ('f1(f2(p1, p2))', 1), ('f1(p1, f2(p2, f3(f4(p1), p2), p1)', 3)]

How to write a function to test if a string contains more than N nested function calls?

Only valid functions calls.

>Solution :

The real answer is that you need a full language tokenizer to handle all cases of parsing function calls where ( and ) may be inside strings or tuples and newlines or whitespace may split things in weird ways.

For fun.. parsing just your well-formed examples, count the opening parentheses ( before any closing ) ones.

tests = [('f1(p1)', 0), ('f1(f2(p1, p2))', 1), ('f1(p1, f2(p2, f3(f4(p1), p2), p1)', 3)]

N = 2
for ts,tn in tests:
    for s in ts.split(')'):
        if s.count('(') > N:
            print(ts, 'has more than', N, 'nested funcs')

Outputs the last expression.