Begin forwarded message: Date: Wed, 8 Sep 1993 12:04:10 -0400 Errors-To: haskell-request Reply-To: haskell Originator: [EMAIL PROTECTED] 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 Sirs: 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 -----