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Path: utzoo!watmath!clyde!caip!lll-crg!seismo!umcp-cs!mangoe
From: mangoe@umcp-cs.UUCP (Charley Wingate)
Newsgroups: net.lang
Subject: Re: compound statements
Message-ID: <2322@umcp-cs.UUCP>
Date: Thu, 10-Jul-86 01:04:53 EDT
Article-I.D.: umcp-cs.2322
Posted: Thu Jul 10 01:04:53 1986
Date-Received: Fri, 11-Jul-86 06:36:42 EDT
References: <5303@topaz.RUTGERS.EDU>
Organization: University of Maryland, Dept. of Computer Sci.
Lines: 51

Silver writes:

>> In languages like Pascal, where there may be functions within
>> functions, it is necessary to have some sort of "end-of-procedure"
>> delimiter. 

>Not true.

>What gives rise to ambiguity is the null statement.  Consider a
>language that allows null statements, and an arbitrary statement as a
>(sub-)program body.  In the following, example, to which procedure
>would the 'writestring' be bound?

># I consider the 'program' keyword to be unnecessary. #
>procedure example (output - text)
>
>  procedure this
>
>    procedure that
>
># the code in question #
>writestring (output, "What procedure calls this statement?")
>====================

>Recall how Pascal resolves 'else' clause ambiguities.  Simply bind it
>to the nearest unclosed 'if-then' (not 'if-then-else') statement.
>That convention is applicable here.  If the definition of the language
>stated that a statement is bound to the nearest unclosed procedure,
>then no ambiguity results.  The 'writestring' statement is bound to
>'that', a null-statement to 'this' and 'test'.

Well, ACCCKK PTHT.  What if you have TWO statements?  Which belongs to whom?

Program X(output);

Procedure Y; { Begin }

   Writeln("A");

{ End; } { Begin }

Writeln ("b"); Y;

{ End. }

Now, with all the begin-end constructs eliminated, how do you tell which
statements belong to which procedure?

(Obviously, the "begins" are all superfluous.  The "ends" aren't, though.)

C. Wingate