Hi Carl,
I believe there is no need to have a further discussion
on this subject in this mailing list, because you said
everything.
Please write a CR with your preferred complete solution.
The TTCN-3 maintenance group can only work based on CRs
in order to have a transparent maintenance procedure.
Regards
Jens
> This is the operator precedence table (section 15.0):
>
> priority | operator type | operator
> | if not binary |
>
+
+
> highest | | ( ... )
> | unary | +, -, *, /, mod
> | | +, -, &
> | unary | not4b
> | | and4b
> | | xor4b
> | | or4b
> | | <<, >>, <@, @>
> | | <, >, <=, >=
> | | ==, !=
> | unary | not
> | | and
> | | xor
> lowest | | or
>
>
> But this operator precedence is not reflected in the EBNF.
> The operator precedence in the EBNF is:
>
> priority | operator type | operator
> | if not binary |
>
+
+
> highest | | ( ... )
> | unary | +, -
> | | *, /, mod
> | | +, -, &
> | unary | not4b
> | | and4b, xor4b, or4b
> | | <<, >>, <@, @>
> | | <, >, <=, >=,==, !=
> | unary | not
> | | and, xor, or
>
> The operators are in these incorrect groupings:
>
> and4b, xor4b, or4b
> <, >, <=, >=,==, !=
> and, xor, or
>
>
> The EBNF should either explicitly separate out different levels
> of precedence like:
>
> SingleExpression ::= XorExpression { or XorExpression }
> XorExpression ::= AndExpression { xor AndExpression }
> AndExpression ::= SingleExpression { and SingleExpression }
>
> Or the EBNF should ignore the operator precedence and refer to
> the table in section 15.0. Something like:
>
> SingleExpression ::= SingleExpression BinaryOp SingleExpression |
> UnaryOp SingleExpression |
> "(" SingleExpression ")" |
> OpCall | Value
> BinaryOp ::= ... /* see section 15.0 for resolving operator
precedence */
>
> My opinion is operator precedence should not be partly explicit
> and partly ignored in the EBNF. Either fully specify the precedence
> or fully ignore it. I have no preference either way, but I am not
> in favour of keeping the current mixed-up EBNF definition for
> expressions.
>
> Cheers,
> --
>
> Carl Cerecke - Software Designer
> Da Vinci Communications Ltd
> Christchurch - New Zealand
>
> TEL : +64 3 3838311
> FAX : +64 3 3838310
> e-mail:
This email address is being protected from spambots. You need JavaScript enabled to view it.
> www :
www.davinci-communications.com
>
>
