Re: [lisp-snmp] Patch to asn.1 to change from parsergen to a modified cl-yacc

[Chun T. (binghe) <bin...@gm...>]

On 2009-2-9, at 15:03, John Fremlin wrote:
>>>>
>>>> ASN.1 10 > (oid "SNMPv2-SMI::mib-2.SNMPv2-MIB::system")
>>>> #<OBJECT-ID SNMPv2-MIB::system (1) [9]>
>>>
>>> This syntax can easily be supported as follows
>>>
>>> (defmethod oid-parse ((source string))
>>> (or
>>>  (with-input-from-string (s source)
>>>    (oid-parse s))
>>>  (with-input-from-string (s (concatenate 'string *asn.1-package-
>>> prefix* source))
>>>    (oid-parse s))))
>>
>> I'm afraid this function cannot work for (oid "SNMPv2-
>> SMI::mib-2.SNMPv2-MIB::system") correctly, you just change it into:
>
> Why do think that?
>
> Look at the function.
>
> First it tries the old way, then it tries with an ASN.1/ prefix.
>
>> (oid "ASN.1/SNMPv2-SMI::mib-2.SNMPv2-MIB::system")
>
> Will this work with the old function? I don't think so, because of
> the .

No, the #\. is NOT the key, and (oid "ASN.1/SNMPv2-SMI::mib-2.SNMPv2- 
MIB::system") do work with the old (current) OID function, you can try  
it yourself. CL readtable is a very good builtin lexer.

>
>
>>
>> How can you solve the second package name "SNMPv2-MIB" in that  
>> string?
>>
>>>
>>>
>>> However, *asn.1-package-prefix* cannot contain a "." because of your
>>> strange readtable. So it must be changed to something other than
>>> "ASN.1/", perhaps "ASN1/"
>>
>> The strange *oid-readtable* is my way to avoid the use of SPLIT-
>> SEQUENCE, it just let #\. be treat as a separator. However, this
>> method can cause unnecessary synbol intern in ASN.1 package, not the
>> best way to read a OID string.
>>
>> Give me more time to think out a better solution please.
>
> Cool
>
>>
>>>
>>>> Well, contact me if you really found your customers use such a MIB
>>>> module name, I think we can talk about this issue later:)
>>>
>>> It's kind of strange that you talk about making your package perfect
>>> but
>>> have it so arranged that by loading in an MIB file one can overwrite
>>> your package itself . . .
>>>
>>> I guess it's not just C programmers who don't care about  
>>> security ;-)
>>
>> The *asn.1-package-prefix* was learnt from Common Lisp's CORBA
>> language mapping. I think you've persuaded me, but I cannot change it
>> until I can solve the OID reader syntax issue above.
>
> Yes, the "." problem is annoying but it can be avoided by using  
> "ASN1/"
> instead . . .

Again, #\. is not the key, it is how to add "ASN.1/" to every "package  
name" in OID string.

>
>
> Thanks for your time
>
> [...]
>

--
Chun Tian (binghe)
NetEase.com, Inc.
P. R. China