RE: [vhdl-200x] Image attribute for array types

From: Martin.J Thompson <>
Date: Wed Jul 23 2014 - 00:43:16 PDT
From: [] On Behalf Of David Koontz

> Why is it you don't have printf type string conversion formats for entire structures or unions in the C 
> programming language?  You could note Ada doesn't generate image strings for values of non-scalar types either.

Conversely, I'd point out that you *do* have this functionality in Python...

Python also has a standard way for objects to define a string representation of themselves (in VHDL-land this would be like overriding/customizing the 'image attribute).  This would be potentially useful to the more complex protected-types.

> It boils down to no one actually needing an entire (and potentially almost unlimited) record or array image on a single line or as a single string.  

I think SW engineers would beg to differ.  And validation work needs much more software-like support in VHDL.

I don't expect this to be synthesisable :)

> Making something simple to use is encouraging it's use without regard to the actual 'cost'.  Sort of like multidimensional arrays going to waveform dump files.

Are you talking about runtime cost, or language development cost?

> The pain of expressing all those record elements by individual image conversion makes a nifty reminder not to do something dumb. For those burdened by that perhaps a smarter text editor is in order instead of gumming up the language.  

I don't regard it as dumb -  maybe I'm too softwarey?

> Or can someone figure out how to place meaningful limits when you've expressed the ability to 'image a record type that can contain elements of record types?

I don't think there should be limits, but that would depend on us adopting some kind of unlimited integer and using it as the index-type for strings.  Which is another debate for another thread I think!


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Received on Wed Jul 23 00:43:47 2014

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