Syntax

Vectors

In Vapour vectors are declared with parenthesis, without the need for c prefix.

Vapour

let x: int = (1, 2, 3)

R

x = c(1, 2, 3)

Range

The : is used to define types in Vapour, so we use .. for ranges.

Vapour

let x: int = 1..10

R

x = 1:10

For loop

The iterator needs to be declared with let.

Vapour

for(let i: int in 1..10) {
  print(i)
}

R

for(i in 1:10) {
  print(i)
}

Return

In Vapour return is a keyword, not a function.

Vapour

func addOne(x: int): int {
  return x + 1
}

R

printIt <- function(x) {
  return(x + 1)
}

Defer

Vapour adds the defer keyword which translates to on.exit, defer expects an anonymous function.

Vapour

func addOne(x: int): int {
  defer (): null => {
    print("second!")
  }

  print("first")
  return x + 1
}

R

addOne <- function(x) {
  on.exit((function(){
    print("second!")
  })())

  print("first")
  return x + 1
}

Declaration & assignment

In Vapour assignment is always done with the = sign, <- is used for something else (see next section).

You also have to declare mutable variables with let, this avoids shooting yourself in the foot overriding variables that you should not.

Vapour

let x: char = "hello"

R

x = "hello"

Assign parent

In Vapour <- is used to assign to a parent variable, where one would use <<- in R.

Vapour

let x: char = "hello"

if(x == "world") {
  x <- "it's world!"
}

R

x = "hello"

if(x == "world") {
  x <<- "it's world!"
}

Constants

We have constants!

info

This is only checked in Vapour, we do not lock the binding in the transpiled code.

Vapour

const x: char = "a constant!"

R

x = "a constant!"

Booleans

Booleans are denoted with true and false.

Vapour

const x: bool = true

R

x = TRUE

Assignments

Vapour supports addition (+=) and substitution assignments (-=).

Vapour

let x: int = 40
x += 2

R

x = 40
x = x + 2