OP is about Scala, where you write directly what you mean, without special operators:

    val usefulMetric = if (wantComplexCalc) {
      complexCalc(foo)
    } else {
      simpleCalc(foo)
    }

Well, that's only "directly what you mean, without special operators" if you come from a C style procedural background and have already internalized all the special operators you've included there, such as parenthesis and braces. Sure, that's most people, but that doesn't mean they aren't operators.

I'd rather have Python's way of doing it, which plays with the order for the sake of readability:

    useful_metric = complex_calc(foo) if want_complex_calc else simple_calc(foo)

Ruby has something similar, and I can't stand it. I think the conditional is the most important item in the phrase, and it's shoved off to the right. If you lead with the conditional, it becomes immediately apparent that the assignment is predicated on the result of a branch.

Ruby (and Python) likely get that from Perl, which has post conditionals, but with specific qualities to prevent them from too much abuse, and which also prevents them from being used in the way presented here (which is why I didn't trot them out earlier, as much as I was tempted by the "you write what you mean" line). The limitations are that there is no else branch, and it only applies to a single statement, so you can't have a block executed with a post conditional. It leads to usage like so:

    die "Invalid param: please enter a positive number" unless $param1 > 0;
    
    $param2 = 0 unless defined $param2;

    return undef if $param1 and not $param2;
    
    my $foo = 1 if $bar; # This unfortunately creates a closure around $foo and is a big source of bugs.

As much flak as Perl gets, quite a lot of thought went into making it flow similar to how people think and talk (which is no surprise if you know Larry Wall is a linguist by training). There were some missteps, but it was very early in this area, so that's expected.

Perl hung onto too many of its warts for too long to stand a chance of competing with Ruby and Python. Only recently has Perl5 introduced real function parameters instead of unrolling @. Flattened lists are another one but the worst is having to specify "use 5.020;" if I'm using Perl 5.20. They've even carried this "tradition" into Perl6 where you have to specify "use v6;" at the top of EVERY damned script. That's progress? Prefixing every variable with "my" is another one which found its way into Perl6. Why can't an advanced language have default lexical scope?

> Only recently has Perl5 introduced real function parameters instead of unrolling @.

Yet there have been modules that support it for years, and with much more features than what was recently rolled out (which was meant to be conservative).

Here's[1] what I said about this quite a while ago. Named parameters with type checking (unfortunately at runtime). I've been writing Perl using different modules (Function Parameters) which use the same syntax for about six years now (for functions, not all the sugar on Moose objects).

> Flattened lists are another one

Flattened lists never cause me a problem. If they cause someone problems, I think they've never really learned what context is in Perl. Once you know how context works in Perl and had a chance to use it to good effect, I can't imagine this complaint persisting. Perl is fundamentally different than most languages in this respect, even if it looks superficially similar to more procedural languages. This is actually a cause of a lot of problems for novice users, because they assume their experience in C/Algol derivatives will map exactly, and where it doesn't people get frustrated.

> but the worst is having to specify "use 5.020;" if I'm using Perl 5.20

What? You don't have to do that. If you want to use newer features that utilize keywords which may conflict with whatever you've written or whatever modules you are using, then yet, you need to opt into those. Perhaps you would have preferred if it silently just broke?

> They've even carried this "tradition" into Perl6 where you have to specify "use v6;" at the top of EVERY damned script.

No, you don't. If you do, and you run it in Perl 5, it will automatically swap out the interpreter for whatever Perl 6 interpreter you have in $PATH though.

> Prefixing every variable with "my" is another one which found its way into Perl6. Why can't an advanced language have default lexical scope?

The requirement to define your variables is not because it's not lexical by default (it is lexical by default, you can use no strict to see). .It's strictness which is enforced, which has been found by the Perl community to be vastly preferably to automatic instantiation of variables because it prevents bugs, and prevents a lot of confusion. You have to define your variable, because the Perl community found that a more sane default.

1: https://news.ycombinator.com/item?id=11633961

Agreed, plus obviously your "if" statement doesn't do the assignment to usefulMetric. One more way the ternary wins (along with functional languages that use "if"s as expressions).

a "final" declaration (in Java) would have pointed that out through a compilation error ;)

D'oh! Fixed. Thanks. :)

Unfortunately, ternary operators eventually end up like this due to refactoring blindness:

  usefulMetric = wantComplexCalc ? 
                   (complexity > 40 ?
                     superComplexCalc(foo) :
                     regularComplexCalc(foo)) :
                   simpleCalc(foo);

At some point you have to rely on policy and not language constraints. I submit that no language is constrained enough to protect against refactoring stupidity while also being flexible enough to be useful to the average programmer on the average project. If not ternary if, it will be something else. So, do you throw out every alternative method to accomplish the same thing, or do you put policies in place to keep the code sane, such as "no chained ternary operators are allowed" ?

In all honesty, I prefer having rules that have no special-case 'unless' issues. It's too much effort/trouble to remember all the cases where things don't work. I'm a good engineer but a terrible compiler.

I believe part of learning a new library/framework/language is to limit yourself to a certain subset of the API offered. After working with Ruby (the language) and Javascript (the ecosystem), I feel like that's the only way to preserve your sanity and productivity. I don't need to know 4 different ways of creating a lambda in Ruby, selecting 1 that can express the other 4 is good enough.

---

In this case, the rule would be no ternary operators, since they work well unless you nest them or unless you make them long/complicated.

Other examples -

You don't need to wrap if conditions unless you have a multi-line body:

  if (myCondition)
    x = 42;
    y = 23;

Early returns simplify short circuiting logic unless your function becomes too long:

  if (myVariableAtBeginningOfFunction) {
    return true;
  }
  ...
  // 2 screens later
  ...
  if (x == 42) {
    return false;  // why am I not getting false?!
  }

Using a variable as a conditional in javascript to test against undefined works well unless the value can be falsy:

  if (person.isStudent) {
    showSchool();
  }

  if (person.age) {
    showBirthCertificate(); // what if age is 0?
  }

> the rule would be no ternary operators

Why not "no nested ternary operators"?

> You don't need to wrap if conditions unless you have a multi-line body

Why not "keep unwrapped if conditions on a single line"?

> Early returns simplify short circuiting logic unless your function becomes too long

Why not "keep functions short"?

> Using a variable as a conditional in javascript to test against undefined works well unless the value can be falsy

Why not "only use conditionals on boolean values"?

I'm not saying your rules are right or wrong, I actually follow a couple of them myself, but your wording implies that other people are simply not following rules, or their rules have a lot of nuances and special cases, but the reality is more likely that their rules are different.

Ultimately we all make different connections and form different patterns in our head. As long as a team can agree on a code style, within a few months everyone starts developing the same cognitive patterns.

It's because it's too easy to lose some of these nuances during refactoring/development blindness. I'd go so far as to say it's inevitable.

If you come into a 3 year old codebase and during the first 2 weeks you need to add extra functionality to a 30-line function with an early return, are you going to refactor the early return? Or are you going to extend it into a 32-line function? What about the new hire after you?

Alternatively, your team has decided to embrace the "only use conditionals on boolean values" philosophy. You're working with a section of code that reads `if (myVar)`. It's been 3 hours, and you don't understand why the code's not working. Suddenly, you realize that at some point `myVar` was refactored from a non-nullable boolean to a nullable number, and someone missed changing this.

And the biggest offender yet - code that is grouped within a file into 'logical sections'. I've never seen this work out. What is a logical grouping for you is a confusing pairing for me. Or maybe it's that I can't immediately grok all 2000 lines of a file I've never seen before, and know where to place the method. This madness around code location is one of the quickest ways to code rot.

---

The perplexing thing to me is that these situations are completely preventable.

If you don't use early returns, scenario 1 won't happen.

Scenario 2 won't happen if you use real comparisons e.g. `if (person.age !== undefined)` (Similarly, `if (person.age != null)` breaks when null and undefined start meaning different things...)

And lastly, a canonical alphabetical/visibility ordering for methods in a file of any length is unambiguous. I don't care what the order is, as long as there is a canonical order.

---

I understand that other teams have their own rules. It's no trouble at all to adjust to things that are purely syntactic differences. But when the rules that are chosen hide lurking semantic pitfalls...I don't know why you'd risk shooting yourself in the foot.

A lot of my strong feelings on code style come from the book Code Complete. I highly recommend that to everyone who hasn't read it. It's filled with examples of confusing/broken code you might inherit, and teaches you how to avoid creating it yourself.

Edit: looks like we hit the HN thread depth limit. Happy to continue this over Twitter, check my profile.

That's just laziness on part of the refactorer. At that point, you need to use an outer if-else statement. Ternary operators are confusing when nested.

what about:

  usefulMetric = wantComplexCalc == false ? simpleCalc(foo)
               : complexity <= 40         ? regularComplexCalc(foo)
               : /* else */                 superComplexCacl(foo)
               ;

Doesn't look much better.