Named Booleans prevent C++ bugs and save you time

Re:Named Booleans prevent C++ bugs and save you time by greggyb on Saturday February 18, 2023 @12:03PM (#34848503)

It is not a direct implementation, and may end up being clunky, but I expect a fairly small library of helper functions could improve ergonomics quite a bit:

Define your booleans as functions of no args. A sample in Python:

    var = 'abc'
    var_contains_a = lambda: 'a' in var
    var_shorter_than_5 = lambda: len(var) < 5

    if var_contains_a() and var_shorter_than_5():
        print(var)

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Re:Named Booleans prevent C++ bugs and save you time by greggyb on Sunday February 19, 2023 @11:05AM (#34858706)

One challenge with the chosen example language, Python, is that functions are truthy. So if you forget to call the function that computes your boolean test, you end up with a default true.

Taking the last top-level statement, the `if`:

    if var_contains_a() and var_shorter_than_5: #note the lack of parens for the second
        print(var)

This will print a string of any length that contains 'a' (or any other collection that implements `in` and does, in fact, contain an element, 'a'). The second function is passed directly as a boolean expression, and being a function, it resolves to true.

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