Re: [sv-bc] Is string allowed to be assigned to any data type?

Thanks Dave,
I understand clearly now. However, if string is used in LHS side, and 
anything non-string type is used in RHS side without casting, is it not 
run time error either?

Regards
Surya



-------- Original Message  --------
Subject: Re:[sv-bc] Is string allowed to be assigned to any data type?
From: Rich, Dave <Dave_Rich@mentor.com>
To: Surya Pratik Saha <spsaha@cal.interrasystems.com>
Cc: sv-ec@eda.org, sv-bc@eda.org
Date: Tuesday, January 29, 2008 6:01:26 AM
> The section on the string data type says this:
>
> "A single character of a string variable is of type byte."
>
> So a[0] is not a string type. It is a byte which is a fixed-sized
> integral type. The rules for bit-stream casting with a fixed sized type
> and an unpacked type require that the source type have the exact number
> of bits as the destination type. If that can be checked at compile time,
> the compiler is free to do that. But if the source involves a dynamic
> type, run-time might be the only time to perform that check.
>
> a[0] = byte'(b);
>
> would be valid only if b had exactly one character, and that check could
> only be performed at run-time.
>
> If you never want this to be an error, then use the streaming operator.
>
> a[0] = {<<{b}};
>
> The only wrinkle in this is whether a string is considered a packed or
> unpacked type. It certainly doesn't qualify as a packed type.
>
> Dave
>
>
>   
>> -----Original Message-----
>> From: Surya Pratik Saha [mailto:spsaha@cal.interrasystems.com]
>> Sent: Sunday, January 27, 2008 5:57 AM
>> To: Rich, Dave
>> Cc: sv-ec@eda.org; sv-bc@eda.org
>> Subject: Re: [sv-bc] Is string allowed to be assigned to any data
>>     
> type?
>   
>> Hi Dave,
>> I did not see anything in the LRM mentioning that restriction.
>>
>> How do I impose a cast here?
>> Is
>> a[0] = byte'(b);
>> valid assignment then?
>>
>> Also without cast, will it be a run time error or compilation time
>> error. LRM does not clearly say assigning integral type to a string
>> variable without cast is run time error or compilation time error.
>>     
> What
>   
>> is your comment on that?
>>
>> Regards
>> Surya
>>
>>
>>
>> -------- Original Message --------
>> Subject: Re:[sv-bc] Is string allowed to be assigned to any data type?
>> From: Rich, Dave <Dave_Rich@mentor.com>
>> To: Surya Pratik Saha <spsaha@cal.interrasystems.com>, sv-ec@eda.org,
>> sv-bc@eda.org
>> Date: Saturday, January 26, 2008 11:17:43 PM
>>     
>>> A single element of a string is a byte, which is an integral type.
>>> It's not legal to assign a string to an integral type without a
>>>       
> cast.
>   
>>> With a cast, b would have to be exactly one character, or you will
>>>       
> get
>   
>>> a run time error.
>>>
>>> Dave
>>>
>>>
>>>       
> ------------------------------------------------------------------------
>   
>>> *From:* owner-sv-bc@server.eda.org
>>>       
> [mailto:owner-sv-bc@server.eda.org]
>   
>>> *On Behalf Of *Surya Pratik Saha
>>> *Sent:* Saturday, January 26, 2008 4:21 AM
>>> *To:* sv-ec@server.eda.org; sv-bc@server.eda.org
>>> *Subject:* [sv-bc] Is string allowed to be assigned to any data
>>>       
> type?
>   
>>> Hi,
>>> As per SV 1800 LRM:
>>> *A string or a string literal can be assigned directly to a string
>>> variable. Integral types can be assigned to a string variable, but
>>> require a cast.
>>> *
>>> This imposes some restriction when LHS of an assignment is a string
>>> type. But is any data type allowed to be LHS when RHS is a string. I
>>> did not see anything in the LRM, though following e.g. is marked as
>>> illegal:
>>> *string b = "";
>>> string a = {"Hi", b};
>>> a[0] = b; // invalid, requires a cast*
>>>
>>> It is not at all clear why the assignment is invalid, how it can be
>>> made valid by casting on which side. Most of the simulators pass the
>>> case though. Is there any mantis or clarification for that?
>>>
>>> --
>>> Regards
>>> Surya
>>>
>>> --
>>> This message has been scanned for viruses and
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>> is
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>>
>>     
>
>
>
>
>
>
>   





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