Re: [xsl] How do I pass the mode as a string?

["Kerry, Richard richard.kerry@xxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

Ok,
Thanks all for the explanations.  I'll look at the alternatives.
If this was C++, which is what I use most of the time (XSL is infrequent, just
when I want to manipulate some XML) I would use some kind of polymorphism to
achieve this.  I'd define a couple of one-line functions with the different
variables, or calls, and pass the appropriate one to the outer function so
they could be run on its results (somewhat garbled, abbreviated explanation,
sorry).  I'm not aware of anything in XSL that looks like polymorphism, but I
would be interested to know if there was a construct that might be similar, or
usable for cases like this one.
Granted I can't construct variable names dynamically, but I can have a number
of variables existing simultaneously and select one and pass it around by
address if I need to.  I don't see an analogous construct in XSL, except to
use choose/when to select a line of code based on an actual variable.

I could send my examples if that would be best, but I think that would provide
a lot of unnecessary code just to show a small bit of context.
What I am actually trying to do is to get a number of XML files processed.
The files are in similar folders, called 'input' and 'output'.  The files'
names follow a couple of name patterns, acq_(\d{4}) and out_(\d{4}). There is
identical code to scan through the folders and identify the files I want to
process (and extract the numbers from the filenames).  They are then passed to
apply-templates with the different modes as mentioned.
So the file scanning, while not especially complicated, is not entirely
trivial and I'd like to have it written just once.  And then, because the
contents of the files differs in structure, they are handled by different
templates, with different modes.




[Blue line]
Richard Kerry
BNCS Engineer, SI SOL Telco & Media Vertical Practice
M: +44 (0)7812 325518
2nd Floor, MidCity Place, 71 High Holborn, London, WC1V 6EA
richard.kerry@xxxxxxxx<https://webmail.siemens-it-solutions.com/owa/redir.asp
x?C=9fb20d019e3e4cb99344d708709a3177&URL=mailto%3arichard.kerry%40atos.net>



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________________________________
From: Michael Kay mike@xxxxxxxxxxxx <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>
Sent: 03 March 2020 11:48
To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx <xsl-list@xxxxxxxxxxxxxxxxxxxxxx>
Subject: Re: [xsl] How do I pass the mode as a string?

Section '6.6.2 in the XSLT 3.0 spec states:


The
xsl:apply-templates<https://eur01.safelinks.protection.outlook.com/?url=https
%3A%2F%2Fwww.w3.org%2FTR%2Fxslt-30%2F%23element-apply-templates&data=02%7C01%
7Crichard.kerry%40atos.net%7Cf54e291885cc4d7f604408d7bf68dcd8%7C33440fc6b7c74
12cbb730e70b0198d5a%7C0%7C0%7C637188329424694875&sdata=eSQdcCjN4EO8jORS463Gpc
DU2L9K0dGwwHP6wU9zJ3o%3D&reserved=0> element also has an optional mode
attribute. The value of this attribute must be one of the following:

  *
an
EQName<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.
w3.org%2FTR%2Fxslt-30%2F%23dt-eqname&data=02%7C01%7Crichard.kerry%40atos.net%
7Cf54e291885cc4d7f604408d7bf68dcd8%7C33440fc6b7c7412cbb730e70b0198d5a%7C0%7C0
%7C637188329424694875&sdata=Fk%2FK%2FfJKIe1TdwQmwpizrP8xMug12fJUDBRGLfJG17g%3
D&reserved=0>, which is expanded as described in 5.1.1 Qualified
Names<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.w
3.org%2FTR%2Fxslt-30%2F%23qname&data=02%7C01%7Crichard.kerry%40atos.net%7Cf54
e291885cc4d7f604408d7bf68dcd8%7C33440fc6b7c7412cbb730e70b0198d5a%7C0%7C0%7C63
7188329424704871&sdata=J9K12tJfdfAz4JxbQAcj9II%2FfTDTxabxPgUUSo5aHv0%3D&reser
ved=0> to define the name of a mode
  *
the token #default, to indicate that the default mode for the stylesheet
module<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.
w3.org%2FTR%2Fxslt-30%2F%23dt-stylesheet-module&data=02%7C01%7Crichard.kerry%
40atos.net%7Cf54e291885cc4d7f604408d7bf68dcd8%7C33440fc6b7c7412cbb730e70b0198
d5a%7C0%7C0%7C637188329424704871&sdata=a6iW12SrGH06RlMcl2h9b8dJI3REzfkYOrO5Au
8g9z4%3D&reserved=0> is to be used
  *
the token #unnamed, to indicate that the unnamed
mode<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.w3
.org%2FTR%2Fxslt-30%2F%23dt-unnamed-mode&data=02%7C01%7Crichard.kerry%40atos.
net%7Cf54e291885cc4d7f604408d7bf68dcd8%7C33440fc6b7c7412cbb730e70b0198d5a%7C0
%7C0%7C637188329424714867&sdata=i6lQizANc28QMchUjq6CdLldwmM57L1PNleISc%2F%2BD
Ho%3D&reserved=0> is to be used
  *
the token #current, to indicate that the current
mode<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.w3
.org%2FTR%2Fxslt-30%2F%23dt-current-mode&data=02%7C01%7Crichard.kerry%40atos.
net%7Cf54e291885cc4d7f604408d7bf68dcd8%7C33440fc6b7c7412cbb730e70b0198d5a%7C0
%7C0%7C637188329424714867&sdata=%2FSSYYInob%2BrZ3Jj5CQK2mqWdJgtpzkoGFsBxM%2FD
ihKs%3D&reserved=0> is to be used

It does not allow an expression, and it does not allow an attribute value
template.

It's similar to trying to refer to a variable by name: you can't construct
variable names dynamically either, however much you feel it would make your
life easier.

You haven't described your problem so it's difficult to suggest a different
approach to solving it. Higher-order functions might be the right way.

Michael Kay
Saxonica