If / Else / While

You can easily check for in-game conditions using Sandstone's builtin if statement, or loop while a condition is true using while.

If Syntax

To check a condition (see ❓Conditions), the following syntax is used:

_
  .if(condition1, () => {
    say('Condition 1 is true')
  })
  .elseIf(condition2, () => {
    say('Condition 2 is true')
  })
  .else(() => {
    say('Both condition 1 and condition 2 are false')
  })

As you can see, this syntax mimics the original if / else if / else construct from classical programming languages.

elseIf and else are optional. You can chain as many elseIf as needed:

_.if(condition1, () => {
  say('I am a lonely if')
})

_
  .if(condition2, () => {
    say(2)
  })
  .elseIf(condition3, () => {
    say(3)
  })
  .elseIf(condition4, () => {
    say(4)
  })

While

Syntax

while uses the same syntax as if:

_.while(condition, () => {
  say('The condition is true')
}

⚠️

Under the hood, while uses recursion. Having a lot of iterations is costly and should be avoided.

Sandstone also implements do while, which always run at least once:

_.doWhile(condition, () => {
  say('The condition is true, or this is the 1st iteration!')
})

Context Modifiers

⚠️

This feature is planned, but not available yet.

When using recursion in Minecraft, you might change the context of each function call. For example, a raycast will go one block further at each recursion.

while gives you the possibility to modify the context at each iteration:

_.while(condition, () => {
  say('The condition is true!')

  return execute.positioned('^ ^ ^1')
})

This example will compile to:

## namespace:main
execute if condition run namespace:main/while

## namespace:main/while
say The condition is true!
execute positioned ^ ^ ^1 if condition run namespace:main/while

Success Callback

⚠️

This feature is planned, but not available yet.

When the condition becomes false, you can run some commands using the latest context. For example, a raycast might change a block when the condition is not met anymore.

This callback is the third argument of the while method:

_.while(condition, () => {
  say('The condition is true')
}, () => {
  say('The condition just became false!')
})

Examples

Give 1 diamond to the player for each kill he has:

const kills = Objective.create('kills', 'playerKillCount')
const i = Variable(0)

_.while(i.lessThan(kills('@s'), () => {
  give('@s', 'minecraft:diamond', 1)
  i.add(1)
})

Raycast until you find a block that’s not air, and replace it with a diamond_block:

_.while(_.block('~ ~ ~', 'minecraft:air'), () => {
  return execute.positioned('^ ^ ^1')
}, () => {
  setblock('~ ~ ~', 'minecraft:diamond_block')
})