From: "Peña, Botp" <botp@...>
Date: 2007-01-20T13:59:37+09:00
Subject: Re: Float to Fixnum (was: Negative Float conversion to Fixnum)

From: Drew Raines [mailto:aaraines@gmail.com] :

#--------------------------------------
# BigDecimal seems to be unaffected, so I guess I'll use that as a
# workaround:
# 
#   >> (39.30*100).to_i
#   => 3929
#--------------------------------------

mixing integers and float is like mixing water w gasoline. expect disasters in all directions.

irb(main):018:0> 39.30*100 == 3930
=> false
irb(main):019:0> 39.30*100 == 3939
=> false

ruby supports integers and floating point numbers (wc in turn are supported by the hw architecture). imho, there's a big gap/hole for the representation of plain decimals (usurped by floating point in this case).

#--------------------------------------
#   >> (39.30*100).to_d.to_i
#   => 3930
#--------------------------------------

indeed. 99% of the my time, i find no use for floats (maybe i'm scared of surprises).

i'd suggest a global $DECIMAL=1 to instruct ruby to bigdecimal mode so that

   >> 39.30*100 == 3930
   => true
   >> (39.30*100).to_i   # no need for to_d there, 39.30 is decimal, right? ;)
   => 3930

i really do not care if it would be slower. i chosed ruby anyway.

kind regards -botp