On Mon, Feb 6, 2012 at 11:59 AM, Rick McGuire <[email protected]> wrote:
>
> Whether it is a number or not is not the issue. The issue is whether
> it is considered a symbol or not during scanning. For example, 3a is
> a symbol token, and it is only when you try to do arithmetic with its
> value do any numeric rules get applied. At issue here is whether the
> scanner rules for exponential notation require this to be interpreted
> as a single token, or two tokens with an operator between. By the
> rules we have in our documentation, then 3ae+6, 3..0+6, and .ae+6
> should all be single tokens. Prior to that "bug fix", only the first
> of these was interpreted as a single symbol token. After the update,
> none of these were. Our working definition, I believe, goes all the
> way back to Mike's original definition. However, I think I just found
> the relevant section in the ANSI standard, which states:
>
> – EXPONENT_SIGN occurs when the character about to be scanned is '+'
> or '-', and the
> characters to the left of the sign, currently parsed as part of
> Const_symbol, represent a
> plain_number followed by 'E' or 'e', and the characters to the right
> of the sign represent a
> repetition of digit not followed by a general_letter or '.'.
>
> So, by this definition, the exponent is only recognized as part of the
> symbol if the token scanned so far is a "plain number" (consisting of
> at least one digit and at most one "."). So by the ANSI definition,
> 3ae+6 should NOT be treated as a single token, but rather as two
> tokens with a operator between then. The error is the correct
> behavior here, and this truly was a bug fix :-)
>
>
Okay, thanks for straightening that out. I didn't have the ANSI standard,
but I just downloaded the pre-publication from RexxLA. Not sure if would
have found that part eventually or not. <grin>
Does our working definition in the docs need to be updated?
--
Mark Miesfeld
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