Begin forwarded message:

Date: Wed, 8 Sep 1993 12:04:10 -0400
Errors-To: haskell-request
Reply-To: haskell
Sender: haskell
Precedence: bulk
From: "Vincent Maiorana" <[EMAIL PROTECTED]>
To: haskers
Subject: Dec_1991_docs
X-Listserver-Version: 6.0 -- UNIX ListServer by Anastasios Kotsikonas


    I have three short questions prompted by my 

 reading of HASKELL, Version 1.2beta, December 1991.

 Question 1 


  Could you describe (or point to a page that describes)
  what is meant by the notation on page 83:

   -- constant function
   const         :: a -> b -> a
   const x _     =  x


  With a copy of Winston/Horn's discussion of Lambda calculus
  in hand, (and I've almost located a paper by Church), 

  I do not understand the  :: a -> b -> a
  expression.  Help !

Question 2

  Could you provide a simple glossary of mathematical notations
  in the next versions of the docs?

  It took a while for me to realize that the => symbol meant

      if p then q (p only if q) a.k.a the 'context operator' 



Question 2a:

        Could you provide an English definition of 

       "expression type signature" versus "type signature". 

        Are they one-in-the-same? I could not find an adequate
        English definition that distinguished the two.

F Y I     C O M M E N T S:


o  The industry language MHDL (based on HASKELL) 

   never defined the => operator! C++ literature 

   does a somewhat better job of defining type defintion 

   and class definitions of types.

o  Perhaps the HASKELL docs could follow the formats of
   introductory (and later in HASKELL) advanced C++ docs.
   See Lippman's C++ or other "primers" for an idea. 


Question 3     

  Could you explain (or point to an explanation) of the Lambda
  production   (page 10)

         exp 10 ->  \apat .. apatn -> exp 

  and how it relates to Winston/Horn's discussion of Lambda
  in their LISP book, chapter 6, "Definition of Lambda"?

  It seems as if the backslant is a LITERAL part of the syntax.
  If that is the case, BNF formatting rules usually require 

  a '\'  as the designation of a literal.

          Thanks !   

          Vincent Maiorana
          Raytheon Company
          Missile System Division  

          Computer Aided Engineering


----- End Included Message -----

Reply via email to