Re: [xsl] Mode in XSLT 3.0

Subject: Re: [xsl] Mode in XSLT 3.0
From: "Michael Kay mike@xxxxxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>
Date: Sat, 22 Jul 2017 16:11:07 -0000
The design doesn't allow you to construct a mode by combining template rules
from two different packages, except for the specific case where a using
package adds overriding template rules to a mode that is defined in a used
package. If that's what you're trying to achieve, then it isn't going to work:
you're trying to create packages that aren't sufficiently independent of each

The thinking is that if package A uses packages B and C, then B and C were
developed and tested independently and have no knowledge of each other or
dependence on each other. When a template rule in B calls apply-templates,
it's not expecting a template rule in C to be invoked, because it was written
with no knowledge of C.

If B and C are designed to process different kinds of document, but both were
written to use the unnamed mode, then to turn them into packages it is
probably best to add a default-mode attribute to the xsl:package element, as
you have done: but you need to use different mode names in the two packages.
This has the effect that all template rules and apply-templates calls that
don't specify a mode are now using the default mode, which can be different
for the two packages; and since the two modes now have different names, both
can be visible in the using package A.

That's the thinking anyway. How well it works in practice is something that I
hope we will discover as the user community shares its experiences.

Michael Kay

> On 22 Jul 2017, at 15:58, Toshihiko Makita tmakita@xxxxxxxxxxxxx
<xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:
> Hi list,
> I'm testing to convert XSLT 2.0 stylesheet modules that have xsl:template
with @match attributes to XSLT 3.0 packages. They belong DITA-OT plug-in and
generates XSL-FO from DITA maps and topics.
> Most of templates are defined with no @mode attributes which means that they
are defined as default mode.
> In XSLT 3.0 package if a template is declared without no @mode attribute, it
is assumed to be "#unnamed" and "#unnamed" mode must be @visibility="hidden".
> Consequently if we want declare templates in a library package as public, we
must declare mode explicitly as following:
> <xsl:package name="urn:package:a" default-mode="MODE_NORMAL" version="3.0">
>  <xsl:mode name="MODE_NORMAL" visibility="public"/>
>  <xsk:template match="v">b&</xsl:template>
>  <xsk:template match="w">b&</xsl:template>
> </xsl:package>
> <xsl:package name="urn:package:b" default-mode="MODE_NORMAL" version="3.0">
>  <xsl:mode name="MODE_NORMAL" visibility="public"/>
>  <xsk:template match="x">b&</xsl:template>
>  <xsk:template match="y">b&</xsl:template>
> </xsl:package>
> The first package:
>  <xsl:use-package name="urn:package:a"/>
>  <xsl:use-package name="urn:package:b"/>
> However XSLT 3.0 specification says that mode name should be unique between
library packages.
> "The components which can be declared in one package and referenced in
another are: functions, named templates, attribute sets, modes, and global
variables and parameters."
> "[Definition: Two components are said to be homonymous if they have the same
symbolic identifier.]"
> "[ERR XTSE3050] It is a static error if the xsl:use-package elements in a
package manifest cause two or more homonymous components to be accepted with a
visibility other than hidden."
> According to the specification, I found it is not useful to apply
xsl:package for the XSLT 2.0 modules that have default mode templates. Is my
understanding accurate?
> --
> /*--------------------------------------------------
> Toshihiko Makita
> Development Group. Antenna House, Inc. Ina Branch
> Web site:
> --------------------------------------------------*/

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