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Re: To allow hex and oct %token values

From: Tim Van Holder
Subject: Re: To allow hex and oct %token values
Date: Thu, 04 Mar 2004 16:35:06 +0100
User-agent: Mozilla Thunderbird 0.5 (Windows/20040207)

Odd Arild Olsen wrote:
- int     [0-9]+
+ int     (0x)?[0-9]+

This does not support 0x20a or 0x20A; that's easy enough to fix,

The main problem is that this is a breaking change - the (few) people
that felt the need to specify specific token numbers may have done so
like this:

   %token FOO     0800
   %token BAR     0801
   %token XYZZY   1077

which is valid according to the current situation. With your change however, it breaks completely. Aside from the fact that you should check that strtoul was able to parse the entire token and given an error if not, the above can no longer work (FOO and BAR would likely both get value 0 or ULONG_MAX, for example, as strtoul will error out when it hits the 8, which isn't a valid octal digit). Adding hex support would not cause such breakage, and may be a valid extension to consider.
I'm also not sure how such changes would impact POSIX compliance.

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