OpenEuphoria

2. RE: namespace

• Posted by Derek Parnell <Derek.Parnell at SYD.RABOBANK.COM> Jul 10, 2002
• 414 views

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> -----Original Message-----
> From: Jiri Babor [mailto:jbabor at PARADISE.NET.NZ]
> Subject: Re: namespace
> 
> 
> 
> Hi, Derek! You wrote:
> 
> >I believe that RDS is considering issuing a warning whenever 
> a declaration
> >overrides another one. However, which behaviour are you 
> upset over - the
> >missing warning or the overriding?
> >
> >I would like the overide functionality to continue. But I 
> wonder if, when we
> >get the warning message facility, the programmer could code 
> something like
> >...
> >
> >  override constant a = 2
> >
> >This would do two things: Skip the message being issued and 
> alert the reader
> >of the code to the fact that the override is deliberate.
> 
> I must admit I do not see your point in having this sort of 
> 'functionality'. If
> the 'constant' is no longer a constant, make it into a 
> variable and simply
> re-assign it.

It's not so much that a 'constant' is changing value, but more that somebody
is using the name I wanted to use. For example, if I use somebody's include
file that just happens to contain the line ...

  global constant True = 1, False = 0

but in my program I also want to use these names, and I don't care what that
somebody is using them for.

  constant True = ".T.", False = ".F."

This is were overriding is useful. Because I no longer have to be concerned
about the names that other people have chosen for identifiers.

> The behaviour is also inconsistent: for instance we are not 
> allowed to override
> user defined routines, where it would be, often, very useful.

You are very correct here. The same principle should apply - I shouldn't
have to worry about the names other people have chosen for identifiers, be
they variables, constants or routines.

However, a warning message would be nice to alert me to a possible mistake I
might be making.

> >Another point, Jiri. The style of coding you demonstrate 
> above, seems to say
> >that you knew that 'a' had been declared in test.e (thus the 
> first "? a"
> >command). You then declare another 'a', knowing that the 
> first one existed.
> >The problem for a code reader is then - is this second 
> declaration a mistake
> >or deliberate?
> 
> Sorry, Derek, that was just an illustration, simplified. In 
> actual case I am
> currently updating a large application with a number of 
> cascading includes,
> cutting and pasting, also using several versions. It just 
> happened I had the
> same constants (flags) declared at different levels with 
> slightly different
> values - and it took me two days to trace the bug...

Point taken.

----------
Derek.

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