python function signature reuse with variations

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Summary

The problem at hand involves reusing a lengthy function signature in multiple functions with slight variations in internal code. The goal is to use first-class functions to reuse the signature and perform conditional branching based on the called function’s name.

Root Cause

The root cause of this issue is the inability to directly access the name of the called function from within a reused function signature. The following causes contribute to this problem:

  • Function aliasing: Assigning a new name to an existing function does not change the original function’s name.
  • Limited introspection: Built-in functions like inspect.currentframe().f_code.co_name only provide the name of the current function, not the called function.

Why This Happens in Real Systems

This issue arises in real systems when:

  • Code duplication is avoided by reusing function signatures.
  • Functionality variations are implemented through conditional branching based on the called function’s name.
  • Dynamic function assignment is used to assign new names to existing functions.

Real-World Impact

The impact of this issue includes:

  • Code maintainability: Repeated function signatures can lead to maintenance issues.
  • Readability: Unclear or duplicated code can decrease readability.
  • Scalability: As the number of functions with similar signatures grows, the problem becomes more pronounced.

Example or Code

def commonFuncCore(a=None, b=None, c=3, funcName='COMMON'):
    print(f'funcName:{funcName} a:{a} b:{b} c:{c}')

def f1(*args, **kwargs):
    commonFuncCore(*args, **kwargs, funcName='f1')

def f2(*args, **kwargs):
    commonFuncCore(*args, **kwargs, funcName='f2')

print('calling f1:')
f1(a=1, b=2, c=5)
print('calling f2:')
f2()

How Senior Engineers Fix It

Senior engineers address this issue by:

  • Passing the function name as an argument: Modifying the reused function signature to accept the called function’s name as an argument.
  • Using wrapper functions: Creating wrapper functions that call the reused function with the desired function name.

Why Juniors Miss It

Junior engineers may miss this solution due to:

  • Limited experience with function reuse and dynamic function assignment.
  • Overreliance on introspection: Focusing too much on built-in functions for introspection, rather than exploring alternative solutions like passing the function name as an argument.
  • Insufficient consideration of code maintainability: Not prioritizing code readability and maintainability when implementing function reuse.