[Haskell-beginners] ghc installation on mac osx 10.4.11(intel), Xcode 2.4?

[7stud]

Hi,

I just bought Real World Haskell, and I'm trying to get the 
ghc compiler set up.  The installer for the latest version 
of ghc, 6.10.1, is for Leopard(osx 10.5).  What should
I install for osx 10.4.11(Tiger)?

Also, a question about "Beware of enumerating floating
point numbers" on p. 11.  The book doesn't explain
what it means to enumerate floating point numbers
without a step, so when it says to beware of 
the non-intuitive behavior of:

ghci> [1.0..1.8]

how would a reader know what the intuitive behavior is?
Is the step .1, .01, .001?  Is there a default 
step?  Who knows?


On p. 10 there is an error.  Below the last code example
 on the page, it says:

"In the latter case, the list is quite sensibly missing the
endpoint of the enumeration, because it isn't an 
element of the series we defined."

But the last line of the code example is this:

ghci> [10,9..1]
[10, 9, 8, 7, 6, 5, 4, 3, 2, 1]

which quite clearly includes both endpoints.