core/rationalizer.rb
# Float#rationalize and String#to_r require complex algorithms. The Regexp
# required for String#to_r cannot be created at class scope when loading the
# core library because Regexp needs to load after String and making a simpler
# Regexp#initialize for bootstrapping isn't really feasible. So these
# algorithms are located here.
#
class String
class Rationalizer
def initialize(value)
@value = value
end
private :initialize
def convert
if m = PATTERN.match(@value)
si = m[1]
nu = m[2]
de = m[3]
re = m.post_match
ifp, exp = nu.split /[eE]/
ip, fp = ifp.split /\./
value = Rational.new(ip.to_i, 1)
if fp
ctype = Rubinius::CType
i = count = 0
size = fp.size
while i < size
count += 1 if ctype.isdigit fp.getbyte(i)
i += 1
end
l = 10 ** count
value *= l
value += fp.to_i
value = value.quo(l)
end
value = -value if si == "-"
value *= 10 ** exp.to_i if exp
value = value.quo(de.to_i) if de
value
else
Rational(0, 1)
end
end
end
end