String format expansion for multi-valued variables

[GersonFeDutra]

Sometimes I need to print values from vectors, arrays and dictionaries in a nice manner, like limiting float decimal places. But having to format each single value individually is a bit boring. So I suggest the above syntax for formatting expansion from a multi-valued (container) variable.

'%{.X}s' % container

Equivalent to:

'%s'.format((func(format):
  var s = '[' + str(container.front())
  for value in container.slice(1, container.size()):
    s += ', ' + format.call(str(value))
  return s + ']'
)((func format(v: float) -> void:
  return '%.Xf' % v)
))

---

Examples:

var vec2 = Vector.ONE
'%{.2}s' % vec2

(1.00, 1.00)

var vec3 = Vector.ONE * TAU
'%{.3}s' % vec2

(6.283, 6.283, 6.283)

var arr = [1, 2, 3, 4, 5, 6]
'%{02.4}s' % vec2

[01.0000, 02.0000, 03.0000, 04.0000, 05.0000, 06.0000]

var bytes = PackedByteArray([1, 2, 4, 8])
'%{08b}s' % bytes

[0b00000001, 0b00000010, 0b00000100, 0b00001000]

var bytes = PackedByteArray([1, 2, 4, 8, 16, 32])
'%{04x}s' % bytes

[0x0001, 0x0002, 0x0004, 0x0008, 0x0010, 0x0020]

var dict = {1.0: 2.5, 2.0: 4.5}
'%{02.0,.2}s' % dict

{01: 2.50, 02: 4.50}

---

Regarding the issue #157 purposed syntax:

var container = [1, 2, PI, 4.5]
f'{container:.2s}'

[1.00, 2.00, 3.14, 4.50]

[Calinou]

%v already exists for Vectors with percent formatting. You can specify the rounding too, e.g. %.3v for 3 decimal placeds.