Ternary operators

[gvarndell]

Originally Posted by Robototes2412

It can also lead to memory leaks.

I think it can also contribute to global warming...

[360skier]

Originally Posted by gvarndell

I think it can also contribute to global warming...

Not to mention put your robot overweight...

[Zme]

we used them a couple of times, primarily where an if statement would be inconvenient, or when we are trying to count outputs (if could result in double counting).

some of our mentors really don't appreciate them, so using them is kinda limited

[Robototes2412]

I use them like sprinkles, with verbose comments following them

[Chris27]

Originally Posted by Robototes2412

Was I the only one that used these on the robot?

For those not in the know, Ternary operators are essentially an inline if statment.

Example using if statements, like mama told you to do so:

boolean getState() {
    if(this.thing.state) {
        return true;
    else {
        return false;
    }
}

Example using the ternary operators:

boolean getStateTernary() {
    return this.thing.state ? true : false;
}

It does the same thing but is way easier.

The layout is:

variable = [boolean condiditon] ? [if its true] : [if its false];

This works in C, C++, Java, and I believe C#.

Did anyone else use these?

I would recommend against coding in this style as not only is it not concise, but there is an overhead to making function/method calls. Why bury a simple boolean test in a bunch of syntax? As a rule of thumb, if you can code something with fewer lines of code, it is typically better to do so.

[FRC4ME]

Originally Posted by Al3+

Technically this could be also written:

return isReversed ^ wpiSolenoid.get(); // if reversed, then flip solenoid value

though the ?: version is arguably more readable.

Once again, it's about clarity of intent. Make it obvious to the reader what you are doing. IMO, if you're choosing what to return conditionally, putting the conditional inside the return statement is more readable (provided, of course, the reader knows what a ternary operator is).

The XOR, on the other hand, would make even someone familiar with that operator stop and think, "now what could he possibly be doing here?"

Originally Posted by LukeS

Yeah, we do all the time. Although, prior to this year I was the only one on the team who knew about them. I distinctly remember explaining them last year, saying that they are the text equivalent of that triangle thing in LabVIEW (bleh!), though apparently no one remembered.

examples from our code:

text output:

C.lcd.lines[0]="compressor:"+(comp.getPressureSwitchValue()?"off":"on");
C.lcd.lines[1]="SideKicker: "+(C.sideKickLoaded<0?"released":"loaded");

flipping a roller based on a switch:

roller.set(C.rollerSpeed*(C.rollerForward?1:-1));

only spinning the extend-able wheels if they're extended

fDrive.set(C.upFront? C.fDrive:0);//if they're up, don't bother
bDrive.set(C.upBack ?-C.bDrive:0);//if they're up, don't bother

Try this:

C.lcd.lines[0] = "compressor:" + (comp.getPressureSwitchValue() 
        ? "off"
        : "on");
C.lcd.lines[1]= "SideKicker: " + (C.sideKickLoaded < 0 
        ? "released"
        : "loaded");

roller.set(C.rollerSpeed * (C.rollerForward
        ? 1
        : -1));

// If they're up, don't bother
fDrive.set(C.upFront
        ? C.fDrive 
        : 0);
bDrive.set(C.upBack 
        ? -C.bDrive
        : 0);

See what some well-placed white space can do for readability? Granted, breaking after ternary operators is my personal preference, but you should at the very least surround your operators with spaces. "Well-placed white space will save mistakes!" Say it with me now...

[LukeS]

Originally Posted by FRC4ME

See what some well-placed white space can do for readability? Granted, breaking after ternary operators is my personal preference, but you should at the very least surround your operators with spaces. "Well-placed white space will save mistakes!" Say it with me now...

Oh, I know, I'm our teams white-space nazi! (if you don't believe me, just check*) I just generally feel that ternaries should be a single line, although, looking at how you did it, I like how newlines looks with text strings. However, I still feel that for the others, a single line is more readable. Looking at the drive code in black, I would probably add more spaces, but with syntax highlighting, I think it's fine how it is.

Also, for text output, the reason the compressor line has NO spaces at all is that with 2 4-character tabs (class and method) we were squeezing for 80 columns (something which I am also a nazi for).

* although, it does look like some spacing got messed up when tweaking numbers in autonomous. I'll fix this and update it today or tomorrow. (that URL is always the newest version)