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Date: Wed, 6 Nov 2013 12:49:26 -0800 (PST)
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Subject: Re: Question about asynchronous calls
From: mockturtle <framefritti@gmail.com>
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Date: 2013-11-06T12:49:26-08:00
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On Wednesday, November 6, 2013 8:54:02 PM UTC+1, Shark8 wrote:

> 
> 
> While it doesn't seem like a big thing: subtypes.
> 
> It's nice not to have to check results of some-function from obviously-incorrect-but-technically-possible values like we have to in C/C++/PHP:
> 
> Ex: Some_Array'Length returns Natural, I don't have to check for -1 whenever I use it.

Thank you for the suggestion.  Actually, I already have something like that in program, with an example taken from some code of mine: a type representing a valid Matlab variable name (I hope the wrap-around does not mess with the code)

type Matlab_Name is new
     String
   with Dynamic_Predicate =>
     (for all I in Matlab_Name'Range =>
        Is_Alphanumeric (Matlab_Name (I)) or Matlab_Name (I) = '_')
     and
       Is_Letter (Matlab_Name (Matlab_Name'First));


I am just beginning to use this, contracts and invariants and it turns out that they are amazing "bug traps."