Ruby Scripting

[kyonides]

Comparisons

In Ruby you have got 3 ways to compare a value of a CONSTANT or variable with any other value.

if or unless statements (plus iterators (loops) like while and until)

Code:

if today == "Sunday"
  print "It's Sunday!"
elsif today == "Monday"
  print "How boring! It's Monday once again..."
else
  print "I just have to drive off to work, you know."
end

Here we were using the == equality operator.

By the way, unless is a negative if statement.

case statement

Code:

case $game_party.actors[0].name
when "Aluxes", "Alex", "Alexis"
  print "He's just an idiot!"
when "Basil"
  print "A fool tailgating another fool..."
when "Hilda"
  print "You should never trust a witch, you know."
end

As you can see in the example above, it's a convenient way to test things. It even allows you to add more than a single value to every single when clause. You could say it's like defining an if statement in a very convenient way.

But there's a catch!

The comparison is always made based on the call to the === identical method.

 ===   would return true.
 ===  would return false, even if they look kind of similar.

An if statement won't force you to use any specific operator for comparisons, you need to define them on every single line of code you're adding to your script.

Enter ? Ternary : Condition

What's a ternary condition?

Well, it's quite simple indeed. It's like an abbreviated form of an if statement. It can also be found in other languages like C and C++.
I guess you could find it useful if you need to test variables in order to find out if you set one value or another. You can also use it to call two distinct methods.

Setting a Variable's Value

Code:

legal_status = age >= 21 ? "Adult" : "Minor"

We used the >= greater than or equal to operator on the example above.

As you have noticed, the variable legal_status will return an Adult or Minor status based on a character's age.

Calling Different Methods

Code:

base_infiltrated? ? explode : business_as usual

In this case we have included three different methods to test if a hypothetical base has been infiltrated by the enemy.
If true, it will simply explode and ignore the third method.
If false, people will ignore the routine check and keep working hard at the military base.

Happy Boolean Return Values!