log10_digit_by_digit.sf

#!/usr/bin/ruby

# Based on code by @catb0t
# https://github.com/trizen/sidef/issues/37

# Computing Logarithms Digit-by-Digit:
#   https://brics.dk/RS/04/17/BRICS-RS-04-17.pdf

func Log10 (x, prec=48) {
  var k = x.float
  gather {
    prec.times {
      take(var d = k.ilog10)
      k = (k / 10**d)**10
    }
  }
}

say log10(1234.56)
say Log10(1234.56).insert(1, '.').join