Path: utzoo!attcan!uunet!lll-winken!lll-crg.llnl.gov!miller
From: miller@lll-crg.llnl.gov (Patrick Miller)
Newsgroups: comp.lang.misc
Subject: Re: Expression Based Language
Keywords: SISAL, typed constructs
Message-ID: <16230@lll-winken.UUCP>
Date: 3 Jan 89 19:21:24 GMT
Sender: usenet@lll-winken.UUCP
Reply-To: miller@lll-crg.llnl.gov.UUCP (Patrick Miller)
Organization: Lawrence Livermore National Laboratory
Lines: 27

In article <9310@ihlpb.ATT.COM> nevin1@ihlpb.UUCP (55528-Liber,N.J.) writes:

>This (using expression forms) won't work too well in (full) C.  
	he problem is that pure
>expression-based languages (like LISP) tend to be typeless as well.
>Having to return a specific data type severely limits the usefulness of making
>control-flow constructs (if, switch, for, etc.) expression-oriented.

Strongly typed functional languages like SISAL support this very concept.
Constructs like:

	IF (test 1) THEN
	    exp 1
	ELSIF (test 2) THEN
	    exp 2
	ELSE
	    exp 3
	ENDIF

are required where exp 1, exp 2, exp 3 are all of the same type.  This is
not as restrictive as one might think.

						Patrick Miller

Patrick J. Miller		miller@lll-crg.llnl.gov
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