Is this a bad idea?

test_float.p6

#!/usr/bin/env perl6
use v6.c;

# see https://en.wikipedia.org/wiki/Single-precision_floating-point_format
sub float(Buf $b) returns Rat {
  my Int $i = $b[3]+<24 +| $b[2]+<16 +| $b[1]+<8 +| $b[0];
  my Int $sign-bit = ($i +& 0b10000000_00000000_00000000_00000000) +> 31;
  my Int $exponent = ($i +& 0b01111111_10000000_00000000_00000000) +> 23;
  my Int $fraction = ($i +& 0b00000000_01111111_11111111_11111111);
  my $thing = ((-1)**$sign-bit) * (1 + $fraction / (2**23)) * (2**($exponent - 127));

  # sometimes $thing is a small Num, so F that. uncomment this line
  # to throw away small Nums... **Is this a bad idea?**
  # $thing ~~ Num ?? 0/1 !! $thing;
}

# test float sub with PI
say float(Buf.new(0xdb, 0x0f, 0x49, 0x40));

# try a bunch of random buffers.
for ^100 {
  try {
    CATCH { default { .Str.say } }
    say float(Buf.new((^256).pick, (^256).pick, (^256).pick, (^256).pick));
  }
}

# output:
#
# 3.14159274
# -184815766020774952960
# Type check failed for return value; expected Rat but got Num (-5.44634129302561e-34)
# Type check failed for return value; expected Rat but got Num (1.46232472745395e-13)
# Type check failed for return value; expected Rat but got Num (-2.59997804933534e-36)
# -933729365187685911625728
# -10339434640959341886177280
# -1349181761705700491264
# -0.00000000030238012
# 12521785258036374543929786236928
# Type check failed for return value; expected Rat but got Num (-7.75945548337306e-16)
# Type check failed for return value; expected Rat but got Num (-2.20862333277913e-14)
# 887489426358272
# 0.1889915
# -35706971677229127895278487436299075584
# -1235545504330660185422954496
# Type check failed for return value; expected Rat but got Num (-8.4933029835363e-26)
# -431510666608640
# 0.00000000682154155
# Type check failed for return value; expected Rat but got Num (-2.56890463303824e-24)
# 0.0000001030326828
# Type check failed for return value; expected Rat but got Num (-1.88907596061435e-15)
# -284.539490
# -9662638846588794691852434952683520
# Type check failed for return value; expected Rat but got Num (9.88364650050003e-34)
# 5377074204464119808
# Type check failed for return value; expected Rat but got Num (-1.2182033776642e-14)
# -1614144809730048
# 229784856221850875831418617856
# 0.00000001324852850
# 16635182080
# Type check failed for return value; expected Rat but got Num (-2.17191308726178e-28)
# Type check failed for return value; expected Rat but got Num (-1.82331140345028e-31)
# 42559149703168
# -442624256320854818816
# Type check failed for return value; expected Rat but got Num (-1.80937747127406e-25)
# 0.00000784685017
# Type check failed for return value; expected Rat but got Num (-3.3224701304099e-32)
# 439863088216027407400275279872
# 1488508362144585880908595200
# Type check failed for return value; expected Rat but got Num (-2.03143717452926e-33)
# -0.094923958
# Type check failed for return value; expected Rat but got Num (-1.26969710244861e-13)
# -26259353986288608178037850112
# 20.6231060
# 29626554384384
# 0.0000001014863429
# 76743579114265648287616860160
# 4455084544
# 52633650372770263520577060864
# Type check failed for return value; expected Rat but got Num (-4.78444919130256e-16)
# -0.00000000028837843
# -28309182464
# 12101708923162502812932058906624
# 76425184213063685870130500076400803840
# -648120948710232251432960
# 543766694886666928128
# 291847445444768579547557548732228567040
# -123285856
# 6704497152
# -48275100354528411648
# 0.58809268
# -594850621685760
# 0.000000000216214394
# -38574330466376220762363101135765504
# 0.00000104667049
# -0.00000001106536285
# Type check failed for return value; expected Rat but got Num (5.08949052139638e-18)
# -188517938686580776262934760259584
# 60675220968772206592
# 92.204483
# Type check failed for return value; expected Rat but got Num (-6.87988157712543e-28)
# Type check failed for return value; expected Rat but got Num (2.5286780807538e-33)
# Type check failed for return value; expected Rat but got Num (-2.70422945604408e-30)
# 0.000120265031
# Type check failed for return value; expected Rat but got Num (1.61772179150216e-23)
# -443779922206484594688
# 2813856644826510274022394218156130304
# -168242988892312681054208
# 910220255693897728
# Type check failed for return value; expected Rat but got Num (4.82236402929119e-26)
# -0.00000000000427319681
# -0.32469904
# Type check failed for return value; expected Rat but got Num (6.11057825318675e-34)
# Type check failed for return value; expected Rat but got Num (-6.28441166259633e-16)
# -0.232138842
# Type check failed for return value; expected Rat but got Num (-8.01459013877391e-26)
# -486818431307962384384
# 570199048192
# 20707272075845396471847640367104
# 75423542395948581200792746196992
# 11389.183594
# -1781205537993126999035108380377088
# Type check failed for return value; expected Rat but got Num (2.40374784617417e-23)
# -984927943076296582496256
# 318007028665866883669355423929991168
# Type check failed for return value; expected Rat but got Num (-3.95462028836968e-29)
# 5.79221010
# Type check failed for return value; expected Rat but got Num (-1.02397990837404e-18)
# 16074211805024772534292185088
# -0.000000000334138411