Truthiness

Every possible value in Rockstar evaluates to either true or false – this is known as truthiness. The only things in Rockstar which are falsy are:

  • false
  • null
  • mysterious
  • the empty string ""
  • the number 0

Everything else is truthy, which means if you put in in a Boolean context (such as the condition of an if statement) it’ll be ‘true’.

Unary Not

Unary not in Rockstar uses the keywords not and non-:

Print not true (prints: false)
Print not false (prints: true)

Print non-true (prints: false)
Print non-non-non-non-non true (prints: false)

Print not 0 (prints: true)
Print not 1 (prints: false)
Print not "" (prints: true)
Print not "false" (prints: false)

Heinous is wrong!
Say Heinous (prints: false)
Bill is non heinous! Say Bill (prints: true)
Bill is non-non heinous! Say Bill (prints: false)
Bill is non-non-NON heinous! Say Bill (prints: true)

Binary Logic

Rockstar supports binary logic expressions using the keywords and, or, and nor.

Print false nor false (prints: true)
Print true nor false (prints: false)
Print false nor true (prints: false)
Print true nor true (prints: false)

Print true and true (prints: true)
Print true and false (prints: false)
Print false and true (prints: false)
Print false and false (prints: false)

Print true or true (prints: true)
Print true or false (prints: true)
Print false or true (prints: true)
Print false or false (prints: false)

Print true and not true (prints: false)
Print true and not false (prints: true)
Print false or not true (prints: false)
Print false or not false (prints: true)

not has the highest precedence, then and, then or, then nor:

Print not true and true (prints: false)
Print not true or true (prints: true)
Print not false and false (prints: false)
Print not false or false (prints: true)

Print true and true or false (prints: true)
Print false and true or false (prints: false)
Print false and false or true (prints: true)
Print true or true and false (prints: true)

Print false nor false or false (prints: true)
Print false or false nor false (prints: true)
Print false nor false or true (prints: true)
Print true nor true or true (prints: true)
print true nor true and false (prints: false)

Binary Logic for Non-Boolean Types

Binary logic applied to strings and numbers in Rockstar doesn’t necessarily return a Boolean result: it returns whichever of the operands resolves the logical constraint of the expression:#

Print "one" or "two" (prints: one)
Print "hello" and 0 (prints: 0)
Print "foo" and "bar" (prints: bar)

Print false or "rock!" (prints: rock!)
Print 0 or null (prints: null)
Print true and "rock!" (prints: rock!)

The and and or operators in Rockstar will short-circuit:

  • X or Y: evaluate X. If the result is truthy, return it, otherwise evaluate Y and return that.
    • If X is truthy, Y is never evaluated.
  • X and Y: evaluate X. If the result is falsy, return it, otherwise evaluate Y and return that.
    • If X is falsy, Y is never evaluated.

In the following examples, short-circuiting means the division by zero is never evaluated:

Print true or 1/0 (prints: true)
Print false and 1/0 (prints: false)
Print true nor 1/0 (prints: false)

Equality and Comparison

Equality in Rockstar uses the is, was, are and were keywords. Equality is determined as follows:

  • If one operand is a Boolean, compare it to the truthiness of the other operand:
    • All non-zero numbers and non-empty strings are equal to true
  • Otherwise, if one operand is a string, compare it with the string representation of the other argument
  • Otherwise, the values of the two operands are compared.
Print 1 is 1 (prints: true)

Your memories are 1. My dreams are 1.
Say your memories are my dreams (prints: true)
It's with 3.
Say your memories are my dreams (prints: false)

Print "rock" is "roll" (prints: false)

Print 0 is true (prints: false)
Print 0 is false (prints: true)
Print 1 is true (prints: true)
Print 2 is true (prints: true)

Print 123 is "123" (prints: true)
Print "yeah!" is true (prints: true)

Inequality

Inequality uses the isn't and ain't keywords.

Watch out for is not: not is the unary negation operator, so a is not b will work as expected when b is a Boolean, but when b is a number or a string, it’ll compare a with the logical not of the truthiness of b

Print 1 ain't 1 (prints: false)
Print 1 isn't 2 (prints: true)
Print 1 ain't 2 (prints: true)

Print false is not true (prints: true)
Print 1 is not 2 (prints: false)

Print "rock" ain't "roll" (prints: true)

Print 123 ain't "123" (prints: false)
Print "yeah!" is true (prints: true)

Identity

To compare values without performing any type coercion, use the exactly keyword, or its aliases really, actually or totally:

Print 1 is 1 (prints: true)
Print 1 is "1" (prints: true)
Print 1 is totally "1" (prints: false)

Print "true" is true (prints: true)
Print "true" is totally true (prints: false)
Print 1 + 1 is totally 2 (prints: true)

Print 1 - 1 is false (prints: true)
Print 1 - 1 is really false (prints: false)

Print 1 + 2 is "3" (prints: true)
Print 1 + 2 is exactly "3" (prints: false)

Heinous is wrong
Bill is right
Say Bill is totally non-non-non-non-NON heinous (prints: true)

Comparison

Rockstar supports the following comparison operators:

  • is higher/greater/bigger/stronger than to denote ‘greater than’
  • is lower/less/smaller/weaker than to denote ‘less than’
  • is as high/great/big/strong as to denote ‘greater than or equal to’
  • is as low/little/small/weak as to denote ‘less than or equal to’

By default, comparison use type coercion:

  • If either operand is a string, it’s compared to the string representation of the other value
    • This means that 10 < "2", because 10 is coerced to the string 10, which is alphanumerically less than the string 2
  • Otherwise, the numeric values of the operands are compared (true is 1, null and false are 0)
Say "a" is greater than "b" (prints: false)

Say "a" is greater than true (prints: false)
Say "z" is greater than true (prints: true)

Say true is greater than "a" (prints: true)
Say true is greater than "z" (prints: false)

Say "123" is greater than 456 (prints: false)
Say "789" is greater than 456 (prints: true)

Say "2" is greater than 10 (prints: true)
Say 10 is greater than "2" (prints: false)

Say 1 is as great as "1" (prints: true)
Say 1 is as great as 2 (prints: false)