Example:

block lenTooLong:
  let ls = @[1, ]
  doAssertRaises IndexDefect:
    discard ls.unpack(2)
  doAssertRaises IndexDefect:
    ls.unpack(a, b)

# Simple unpacking - you need to provide the length to unpack
let (a, b, c) = @[1, 2, 3, 4].unpack(3)
doAssert (a + b + c) == 6

# When unpacking with length you get a tuple so you can assign it
# to something like let (a, b, ...) = x later
doAssert @[1, 2, 3, 5].unpack(2) == (1, 2)

# You can call unpack with variable names so you don't have to provide
# the length to unpack
# You can also optionally use `_` for values you don't want to get
@[1, 2, 3, 5, 6].unpack(g, x, _, _, z)
doAssert (g + x + z) == 9

# Finally, this macro supports Python-like star expressions
# for variables:
let data = @[1, 2, 3, 4, 5, 6]
data.unpack(valA, valB, valC, *valY, valG)
doAssert (valA + valB + valC + valG) == 12
# For star expressions you get sequences
doAssert valY == @[4, 5]

data.unpack(start, *ends)
doAssert start == 1
doAssert ends == @[2, 3, 4, 5, 6]

# *_ means "ignore al values until the next variable"
data.unpack(k, r, *_, f)
doAssert k == 1
doAssert r == 2
doAssert f == 6

# You're not limited to simple expressions, you can call this
# macro with somewhat complex expressions or variables
let values = @[3, 2, 5, 7]
doAssert values.unpack(4) == (3, 2, 5, 7)

import std/strutils
"how are you".split().unpack(ca, cb, cc)

doAssert @[ca, cb, cc].join(", ") == "how, are, you"

Example:

@[1, 2, 3].unpackValues (a, b, c)
doAssert [a, b, c] == [1, 2, 3]