hi rob, from the docs we have:

Coerces both arguments to Numeric (if necessary); returns True if they are equal. 
> my $x = 1/10;   #0.1
> $x.^name;       #Rat

> my  $y = 3602879701896397/36028797018963968;   #0.100000000000000006
> $y.^name;       #Rat

> $x == $y         #False   (no coercion necessary)
> $x == 0.1        #True     (no coercion necessary)
> $y == 0.1        #False   (no coercion necessary)
so comparing without coercion works as you expect

> 0.1e0.^name;  #Num
> $x == 0.1e0    #True    (coerces $x to Num, then compares)
> $y == 0.1e0    #True    (coerces $y to Num, then compares)

coercion from Rat to Num can result in loss of precision
> say $y.nude   #(3602879701896397 36028797018963968)
> say $y.Num    #0.1     
coercing this particular Rat to a Num collapses it to 0.1
IIRC the limit of Rat precision is e-14 ish (it gets lumpy), 
so in the general case it is fair to round away your ...00006 to 0
thus the Num 0.1 maps to both of these Rat options

[download]

your python example does much the same...

print (Fraction(3602879701896397, 36028797018963968) == 0.1); # True

In reply to Re^2: Research into occasional participation in Perl/Raku development by p6steve
in thread Research into occasional participation in Perl/Raku development by talexb

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