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Re: [Scheme-reports] 7.1.1 lexical structure
- To: Andy Wingo <wingo@x>
- Subject: Re: [Scheme-reports] 7.1.1 lexical structure
- From: Alex Shinn <alexshinn@x>
- Date: Thu, 19 May 2011 23:49:09 -0700
- Cc: scheme-reports <scheme-reports@x>
- In-reply-to: <email@example.com>
- References: <firstname.lastname@example.org>
On Thu, May 19, 2011 at 1:58 PM, Andy Wingo <wingo@x> wrote:
> What is the deal with PECULIAR IDENTIFIER? Is +.+ useful for someone?
> It seems an odd production, given that implementations are free to
> extend the set of valid identifiers. The R5RS was clearer here.
The English rule is very simple:
[...] in all implementations a sequence
of letters, digits, and ``extended alphabetic characters'' that
does not have a prefix which is a valid number is an identifier.
This was chosen to allow a wide range of new identifiers,
leave room for numeric extensions, and remove _all_ of
the hard-coded peculiar identifiers found in R5RS and R6RS.
Unfortunately, since BNF doesn't have "exception" rules
the actual rules are a little clumsy.
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