snmpconf some language issues

[Steve Moulton <moulton@xxxxxxxx>]

There has been some language issues discussion among a few people
that needs to be forwarded to the list.  Here it is.

	- Steve

---

Steve,

A quick read of the comments suggests that we should post to the main
list. I do not agree with all the proposed changes, but they indicate at
least one engineers questions on reading the current draft. If ray has a
question, then others might. Even if we choose not to include goto (and
for now I would probably come down on the side of not including int), we
can answer the question. 

I do not see any show stoppers here though.
/jon
> 
> Ray is working his way through the language in building a compiler,
> and the following issues have come up in the -05 draft in the
> repository.  
> 
> 	- Steve
> 
> 
> ------- Forwarded Message
> 
> From: Ray Byler <ray@snmp.com>
> Message-Id: <200103162037.PAA20909@mudlark.snmp.com>
> To: moulton@snmp.com
> 
> The policy language document doesn't define what
> "break" and "continue" do.  Are 
> their actions the same as in C i.e. break causes
> the innermost enclosing loop to be exited immediately.
> 
> If this is the case then you might want to consider
> adding goto to the jump statements (and a label to go
> with it).  This would allow you to jump out of all
> enclosing loops to a label for some sort of special
> handling.
> 
> ========================================================
> 
> Also the language as written allows us to do things we
> probably don't want to do with string_literals and
> char_constants. For example, 
> 
> string_literal --> primary_expression --> 
>     postfix_expression --> unary_expression
> 
> char_constant  --> primary_expression --> 
>     postfix_expression --> unary_expression
> 
> allows us to write things like:
> 
>             "abc" = 99;
>             'c'   = 4;
> 
> Many C language definitions allow this too, 
> leaving it to C type-checking to catch.  Is each
> developer on his own to figure out what is allowed
> for LHV and RHV?
> 
> ========================================================
> 
> Since all variables are in the same scope, I'm assuming
> that once declared, variables stay around and are not
> discarded on leaving a block.
> 
> Having all variables in a single scope and allowing them to
> be declared anywhere presents a problem.
> 
>         var a = 5;
> 
>         var a;
> 
> Does the value of a remain 5, or is it reinitialized?  The
> simplest solution, of course,  is simply not to allow it 
> i.e. redefinition of a variable should be a semantic error.
> 
> ========================================================
> 
> Do we want to allow variables to have the same names as
> library functions e.g. "var writeVar = 5;" ?
> It greatly simplifies things if we don't allow this.
> 
> ========================================================
> 
> If the use of a reserved word such as "auto" must cause
> a RTE, then the lexer has to be expanded to check for all
> these reserved words.  That greatly expands the size of 
> the lexer in a limited-memory environment.  It would be
> better to make this a recommendation and not a requirement.
> 
> ========================================================
>  
> 
> ------- End of Forwarded Message
> 
> 
> 
> 

Thanks,
/jon
--

Jon Saperia		     saperia@jdscons.com
			     Phone: 617-744-1079
			     Fax:   617-249-0874
			     http://www.jdscons.com/

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