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Re: Formal spec; implementation; nesting

This page is part of the web mail archives of SRFI 62 from before July 7th, 2015. The new archives for SRFI 62 are here. Eventually, the entire history will be moved there, including any new messages.



Sorry, cut/pasted too quickly:

 <comment> -> <datum-comment> | <quote-comment> | ; <all-chars-to-break>

 <datum-comment> -> #; <datum-or-empty>

 <datum-or-empty> -> <datum> | <datum-comment> | <quote-comment> | <empty>

 <quote-comment> -> '  <comment-or-empty>
                  | `  <comment-or-empty>
                  | ,  <comment-or-empty>
                  | @, <comment-or-empty>

 <comment-or-empty> -> <datum-comment> | <quote-comment> | <empty>


> From: Paul Schlie <schlie@xxxxxxxxxxx>
> 
>> From: Alpine Petrofsky <al@xxxxxxxxxxxxx>
>> 
>> I encourage anyone who would like to see different behavior
>> standardized to provide a formal specification of what he desires.
> 
> This should do it, and feels somewhat simpler:
> 
>  <comment> -> <datum-comment> | ; <all-subsequent-chars-up-to-a-line-break>
> 
>  <datum-comment> -> #; <datum-or-comment>
> 
>  <datum-or-comment> -> <datum> | <datum-comment> | <empty>
> 
> Which should satisfy the following reader scenarios:
> 
>  (#; <a> #; '<b>) => ()
>  (<a> #; #; '<b>) => (<a>)
>  (#; #; <a> '<b>) => ('<b>)
>  (<a> '<b> #; #;) => (<a> '<b>)
> 
> Where if it's also desired to define what ' ` , mean if applied to <empty>,
> then comment need only be extended with a definition of <quote-comment>:
> 
>  <comment> -> <datum-comment>
>             | <quote-comment>
>             | ; <all-subsequent-chars-up-to-a-line-break>
> 
>  <quote-comment> -> ' <empty> | ` <empty> | , <empty> | @, <empty>
> 
>   (although basically cheating, vs re-writing ' ` , @,  patterns)
> 
> Which should satisfy the following further reader scenarios:
> 
>  (' #; <a> ') => ()
>  (' <a> #; ') => ('<a>)
> 
> As although quoting <empty>, or commenting <empty> is redundant, there seems
> no good reason to generate an error; just as quoting a <literal> is also
> redundant and doesn't generate an error.