control.nok

if <- { |condition, then, else|
    __nokBuiltinIf condition then else
}

test {
    a <- false
    if false { a := true }
    assert: ! a
    if true { a := true }
    assert: a
}

unless <- { |condition, args...|
    if (! condition) args...
}

test {
    a <- false
    unless true { a := true }
    assert: ! a
    unless false { a := true }
    assert: a
}

repeat <- { |n, body|
    while {> n 0} {
        body!
        n := - n 1
    }
}

test {
    n <- 0
    repeat 10 { n := n + 1 }
    assert: = n 10
}

switch <- { |topic, clauses...|
    for (pairNeighbors clauses) { |clause|
        if (= topic (nth clause 0)!) {
            (nth clause 1)!
            break!
        }
    }
}

test {
    n <- 0
    switch 2
    | {1} { n := 1 }
    | {2} { n := 2 }
    | {3} { n := 3 }
    assert: = n 2
}