[Gm2] Re: LENGTH() on Solaris 10/sparc

[john o goyo]

Andreas:

On 24-Jul-10, at 2:20 PM, Fischlin Andreas wrote:
> Hi John,
>
> Sorry, I don't quite get your issue.
>
> On 24/Jul/2010, at 04:27 , john o goyo wrote:
> > Examination of the failed test cases shows a real oddity.
> >
> > In a call to LENGTH(s), where s is a string, HIGH(s) is passed as  
> > zero and LENGTH(s) is always 1.
>
> HIGH(s) is passed as zero has nothing to do with LENGTH(s).
[..]
> Perhaps you are actually talking about something else, but then you  
> should explain better what kind of oddity you actually mean.

I wrote the above in the context of gm2, specifically, in the context  
of the failed test cases of Length().  I shall elucidate.

In gm2, LENGTH() is defined in terms of Length() under certain  
circumstances.  If you read the comment before the function Length()  
in M2RTS.mod, you will find the following.

(*
    Length - returns the length of a string, a. This is called whenever
            the user calls LENGTH and the parameter cannot be  
calculated
            at compile time.
*)

In the failed test case iso/run/pass/tstLength.mod, the value of  
LENGTH(s) is compared to the value of Length(s), where "s" is an  
array of characters.  The former is converted into a call to the  
latter and the latter uses HIGH(s) in its count.  Unfortunately, as I  
wrote above, HIGH(s) is zero and consequently Length(s) returns 1,  
hence LENGTH(s) returns 1.

john