🚀 go-pugleaf

In article <farrell.718005712@coral>, farrell@coral.cs.jcu.edu.au (John Farrell) writes:
|> In <BvGz2u.2rv.1@cs.cmu.edu> spot@CS.CMU.EDU (Scott Draves) writes:
|> >i've written a lot of SML and lisp code, and my experience is that
|> >syntax (especially ()s) is not a problem in lisp, but that i do have
|> >problems (understanding and writing) SML.
|> 
|>   Sorry, I just don't believe you. To me, Lisp has the most disgusting syntax
|> imaginable. However I don't like the ML/Haskell convention of using
|> "let x = y in z" rather than "z where x = y", I like to read programs top down
|> rather than bottom up. I have considered having a PC opinion about this
|> syntax, i.e. you like what you're used to, but I honestly believe that Lisp
|> syntax is inherently evil.
|> 
|> John

I don't believe him either, John, but just to pick up on the let/where business:

Consider 
   let x = y in if a then b else c
and
   if a then b else let x = y in c

Now consider

    if a then b else c where x = y

To which of the let forms does this correspond?

It's ambiguous, and an arbitrary decision has to be made as to which parse to
use. This is dangerous, as a wrong assumption can result in a syntactically
correct program with entirely the wrong meaning.

So, the let form if better, because it's safer. Otherwise, it's just personal
preference, which is not a very good way to design a language, expecially where
there's a committee with varying preferences!

BTW, Haskell has a where form as well, but it's part of the equation syntax, not 
the expression syntax, so it doesn't cause any problems.

--brian

-- 
Internet: brian@comp.vuw.ac.nz
Postal: Brian Boutel, Computer Science Dept, Victoria University of Wellington,
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