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XQuery: A.4 Precedence Order

From: Michael Dyck <jmdyck@ibiblio.org>
Date: Mon, 16 Dec 2002 00:34:05 -0800
To: public-qt-comments@w3.org
Message-id: <3DFD8FFD.C9C828FB@ibiblio.org>

XQuery 1.0: An XML Query Language
W3C Working Draft 15 November 2002

A.4 Precedence Order

"In the cases where a number of statements are a choice at the same
production level, the expressions are always evaluated from left to right."

    Presumably, "statements" should be "expressions".

    The phrase "a choice at the same production level" is somewhat vague.

    And the order in which the *expressions* are evaluated is immaterial.
    For example, in the AdditiveExpr A - B - C, the order in which you
    evaluate A, B, and C doesn't matter; what matters is the order in which
    you evaluate the subtractions.

    Here's something that adresses these points, and comes closer to using
    standard terminology:
        When a production directly derives a sequence of expressions
        separated by binary operators, the operators are evaluated from
        left to right.

    In any event, an example might help.

-Michael Dyck
Received on Monday, 16 December 2002 03:41:23 GMT

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