[New Rule] Enumeration of 4 or more variables

[MartinThoma]

Explanation

A code smell I see sometimes is enumeration of variables where an iterable should be used, e.g. a list.

Using a list has several advantages:

• Extendability: If foo1, foo2, foo3, foo4 exist, maybe there will also be foo5 in future?
• You can iterate: If you want to do an action on all of the foo-variables, it's easier
• Maintainability: Renaming foo is easier than foo1-foo4; passing foo as a parameter is easier than passing foo1-4

Example

# Bad
foo1 = "bar"
foo2 = "baz"
foo3 = "42"
foo4 = "1337"

# Good
foo = ["bar", "baz", "42", "1337"]

False-Positives

Just looking for a number in the end would have a quite high chance of false-positivies, e.g.:

• Up to 3 might be acceptable, e.g. for coordinates x1 , x2, x3 is not too uncommon.
• Some names could have 4 at the end, e.g. ieee754

Hence I would look for variables where the direct siblings are 1-4 (or more)