[Xpath-ng] Number literal and string conversion rules in FIXPath

[Uche Ogbuji]

In FIXPath I changed the grammar snippet at #NT-Number

from

[30]   Number   ::=   Digits ('.' Digits?)? | '.' Digits 

to

[30]   SimpleNumber ::=   Digits ('.' Digits?)? | '.' Digits 
[100]  Number       ::=   SimpleNumber (('e' | 'E') ('+' | '-')? SimpleNumber)?

This is off-head for sci notation.  I haven't tested it in a lexer.  If this 
stands, we can renumber the grammar later.

I also modified #function-number to:

<p class="xpath-deviation">a string that consists of optional whitespace 
followed by an
optional minus sign followed by a <a href="#NT-Number">Number</a>
followed by whitespace is converted to the IEEE 754 number that is
nearest (according to the IEEE 754 round-to-nearest rule)
to the mathematical value represented by the string.  A string containing 
"INF", "+INF", or "-INF", surrounded only by optional white space is converted 
to infinity in the first case, infinity in the second case, and negative 
infinity in the third case.</p>

Yeah the wording can be simplified, but I have to move on to something else 
just now  :-)  I'll put in any re-write anyone offers in the interim.


-- 
Uche Ogbuji                                    Fourthought, Inc.
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