Blocks

Yield Patterns

Write functions that accept and yield to blocks.

Reference

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Sourceupstream/blocks/yield_patterns.vibe
def times(n: int, &block: int -> any)
  i = 0
  while i < n
    yield(i)
    i = i + 1
  end
end

def first_truthy(max_attempts: int, &block: int -> bool) -> bool?
  attempt = 0
  while attempt < max_attempts
    result = yield(attempt)
    if result
      return result
    end
    attempt = attempt + 1
  end
  nil
end

def benchmark(&block: () -> int) -> { result: int, elapsed: float }
  start = Time.now
  result = yield
  elapsed = Time.now - start
  { result: result, elapsed: elapsed }
end

def tap(value: int, &block: int -> any) -> int
  yield(value)
  value
end

def transform_keys(
  hash: hash<string, int | string>,
  &block: string -> string
) -> hash<string, int | string>
  result: hash<string, int | string> = {}
  hash.keys.each { |key|
    new_key = yield(key)
    result[new_key] = hash.fetch(key)
  }
  result
end

def run -> { tap: int, times: array<int>, transform_keys: hash<string, int | string> }
  collected: array<int> = []
  times(5) { |i|
    collected = collected + [i]
  }

  tapped = tap(42) { |v|
    v * 2
  }

  keys = transform_keys({ name: "Alice", age: 30 }) { |k|
    k
  }

  {
    times: collected,
    tap: tapped,
    transform_keys: keys
  }
end

Output

Click Run example to see the result.

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