SI Prefixes for Io

SiPrefixes.io

# -- SiPrefixes.io --

#
# convenience Number methods essential 
# for dealing with large scale ranges
# eg. EE calculations
#
# Ex:
#   24 giga
#   2.400000e+010
#

SiPrefixes := Object clone do (
    tonic := method(self * 10**0)
    deca  := method(self * 10**1)
    centa := method(self * 10**2)
    hecto := method(self * 10**2)
    deci  := method(self * 10**(-1))
    centi := method(self * 10**(-2))

    kilo  := method(self * 1000**1)
    mega  := method(self * 1000**2)
    giga  := method(self * 1000**3)
    tera  := method(self * 1000**4)
    peta  := method(self * 1000**5)
    exa   := method(self * 1000**6)
    zetta := method(self * 1000**7)
    yotta := method(self * 1000**8)

    milli := method(self * 1000**(-1))
    micro := method(self * 1000**(-2))
    nano  := method(self * 1000**(-3))
    pico  := method(self * 1000**(-4))
    femto := method(self * 1000**(-5))
    atto  := method(self * 1000**(-6))
    zepto := method(self * 1000**(-7))
    yocto := method(self * 1000**(-8))
)

_Prefixes := list("tonic", "kilo", "mega", "giga", "tera", "peta", "exa", "zetta", "yotta")
_PrefixesNeg := list("tonic", "milli", "micro", "nano", "pico", "femto", "atto", "zepto", "yocto")

SiPrefixesIntrospect := Object clone do (
    siPrefix := method(
        // Nb. parametric log is bugged but seems okay at base 1000
        // + roundDown is truncate, sometimes things will appear right of the decimal
        scale := self log(1000) roundDown
        prefix := if(scale > 0,
            _PrefixMap at(scale min(9)),
            _PrefixMapNeg at(scale min(9)))
        
        list(self / scale, prefix) join(" ")
    )
)

Number appendProto(SiPrefixes)
Number appendProto(SiPrefixesIntrospect)