Path: utzoo!attcan!uunet!lll-winken!ames!hc!lanl!jlg
From: jlg@lanl.gov (Jim Giles)
Newsgroups: comp.lang.fortran
Subject: Re: An exercise in futility (was Results of the UGLY code)
Message-ID: <7962@lanl.gov>
Date: 13 Jan 89 01:50:44 GMT
References: <583@mbph.UUCP>
Organization: Los Alamos National Laboratory
Lines: 34

I haven't read this group for some months so I missed this discussion.
But, there is nothing ambiguous about this example in the standard.
> 
>>      K = 0
>>      DO 10 I = 1,10
>>    1   IF (I.EQ.1.OR.I.EQ.5) GOTO 10
>>        DO 10 J = 1,10
>>          IF (J.EQ.3) GOTO 10
>>   10 K = K + 1
>>      PRINT *,K
>>      END
>

According to the standard:

        11.10.1 Range of a DO-Loop.  The range of a DO-loop
        consists of all the executable statements that appear
        following the DO statement that specifies the DO-loop, up to
        and including the terminal statement of the DO-loop.

So, the statement labeled 10 in the above is within the range of
the innermost DO-loop.  Now, again the standard:

        11.10.8 Transfer into the Range of a DO-Loop.  Transfer of
        control into the Range of a DO-loop from outside the range
        is not permitted.

So, the conditional GOTO on the statement labeled 1 is NOT standard
conforming since it transfers control to a statement that is inside
the range of the inner loop.  Confusion on this point only arises
because Do-loops are allowed to share terminal statements - probably
a bad idea, but we're stuck with it now.

J. Giles