gistfile1.nim

## Hard-coded implementations of the submatrix operator

proc `{}`*[T](m: TMatrix[T, range[0..1], range[0..1]], n: range[10..99]): T =
  let therow = n div 10 mod 10
  let thecol = n mod 10
  result = m[if therow == 1: 0 else: 1][if thecol == 1: 0 else: 1]

proc `{}`*[T](M: TMatrix[T, range[0..2], range[0..2]], n: range[10..99]): TMatrix[T, range[0..1], range[0..1]] =
  let therow = n div 10 mod 10
  let thecol = n mod 10
  for i in 0..2:
    if i == therow:
      continue
    for j in 0..2: 
      if j == thecol:
        continue
      let ro = if i < therow: i else: i -1
      let co = if j < thecol: j else: j -1
      result[ro][co] = m[i][j]

when isMainModule:
  var a, b: TMatrix[int, range[0..2], range[0..2]]  # 3x3 matrix
  var c: TMatrix[int, range[0..1], range[0..1]]

  a = [[ 1, -5,  3], 
       [ 0, -2,  6], 
       [ 7,  2, -4]]

  b = [[-8,  6,  1], 
       [ 7,  0, -3], 
       [ 2,  4,  5]]

  c = [[ 4,  8], 
       [ 7, -2]]

  var v: TVector[int, range[0..1]] = [2, 4]
  assert(+a           == a)
  assert(-a           == [[-1, 5, -3], [0, 2, -6], [-7, -2, 4]])
  assert b.transposed == [[-8, 7, 2], [6, 0, 4], [1, -3, 5]]
  assert a + b        == [[-7, 1, 4], [7, -2, 3], [9, 6, 1]]
  assert a - b        == [[9, -11, 2], [-7, -2, 9], [5, -2, -9]]
  assert a.row(1)     == [0, -2, 6]
  assert a.col(2)     == [3, 6, -4]
  assert a*b          == [[-37, 18, 31], [-2, 24, 36], [-50, 26, -19]]

  var d = [[1, 2],
           [3, 4]]
  assert d{10} == 2
  assert a{20} == [[-5, 3], [-2, 6]]

  echo("Sucessfully tested! No STDs found trololol.")