Re: [Wikitech-l] A question about templates parsing and caching
2011/4/11 Daniel Friesen li...@nadir-seen-fire.com
Side thought... why a #switch library? What happened to the old
{{Foo/{{{1}}}|...}} trick?
Simply, {{Foo/{{{1}}}|...}} links to different pages, while
{{Foo|{{{1}}}|...}} points to the same page. I had been frustrated when I
tried to use Labeled Section Transclusion to build template libraries :-),
that would be an excellent way to build collection of objects into a wiki
page, both of methods and attributes... ... but #lst doesn't parse raw
wiki code from scratch. If it would (t.i.: if #lst would read wiki code
as it is, before any parsing of it, ignoring at all the code outside
labelled section: t.i. ignoring noinclude, html comment tags... anything)
interesting scenarios would raise.
But, if there's no performance gain with {{Foo|{{{1}}}|...}} trick, I'll use
{{Foo/{{{1}}}|...}} for sure. KISS is always a good guide line. :-)
Alex
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Re: [Wikitech-l] A question about templates parsing and caching
On 11-04-11 12:05 AM, Alex Brollo wrote:
2011/4/11 Daniel Friesenli...@nadir-seen-fire.com
Side thought... why a #switch library? What happened to the old
{{Foo/{{{1}}}|...}} trick?
Simply, {{Foo/{{{1}}}|...}} links to different pages, while
{{Foo|{{{1}}}|...}} points to the same page. I had been frustrated when I
tried to use Labeled Section Transclusion to build template libraries :-),
that would be an excellent way to build collection of objects into a wiki
page, both of methods and attributes... ... but #lst doesn't parse raw
wiki code from scratch. If it would (t.i.: if #lst would read wiki code
as it is, before any parsing of it, ignoring at all the code outside
labelled section: t.i. ignoring noinclude, html comment tags... anything)
interesting scenarios would raise.
But, if there's no performance gain with {{Foo|{{{1}}}|...}} trick, I'll use
{{Foo/{{{1}}}|...}} for sure. KISS is always a good guide line. :-)
Alex
Pointing to different pages is essentially the point of the trick.
[[Template:Library]] =
{{#ifexist:Library/{{{1}}}|{{Library/{{{1}}}|...}}|There is no library
function by the name {{{1}}}.}}
[[Template:Library/a]] = Do a
[[Template:Library/b]] = Do b
{{library|a}} = Do a
{{library|b}} = Do b
It essentially works the same as:
[[Template:Library]] = {{#switch:{{{1}}}|a=Do a|b=Do b|There is no
library function by the name {{{1}}}.}}
Except you don't create an obscenely large preprocessed hierarchy which
is cloned in it's entirety to multiple places and expanded multiple
times just to get access to multiple pieces of the library.
Though, when we're talking about stuff this complex... that line about
using a REAL programming language comes into play...
Would be nice if there was some implemented-in-php language script
language we could use that would work on any wiki. I had a project
playing around with that idea but it's dead.
~Daniel Friesen (Dantman, Nadir-Seen-Fire) [http://daniel.friesen.name]
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Re: [Wikitech-l] A question about templates parsing and caching
2011/4/11 Daniel Friesen li...@nadir-seen-fire.com
Though, when we're talking about stuff this complex... that line about
using a REAL programming language comes into play...
Would be nice if there was some implemented-in-php language script
language we could use that would work on any wiki. I had a project
playing around with that idea but it's dead.
~Daniel Friesen (Dantman, Nadir-Seen-Fire) [http://daniel.friesen.name]
Are you a wikisource contributor? If you are, I guess that you considered
too this syntax, pointing to what I wrote into my last message:
{{#section:Foo|{{{1} but... it refuses to run, if section {{{1}}} of
page Foo is a method (while its runs obviuosly if section is an
attribute). :-)
Alex
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Re: [Wikitech-l] A question about templates parsing and caching
On 11/04/11 02:51, Daniel Friesen wrote:
On 11-04-10 06:13 PM, Tim Starling wrote:
[...]
I think it's fair to constrain parser functions to require that they
return the same result for the same arguments, during a single parse
operation. That's all you need to do to have an effective expand() cache.
[...]
-- Tim Starling
That /might/ work nicely for #ask.
However Counter, ArrayExtension, Variables, Random, etc... won't play
nicely with that.
Perhaps a way for parser functions to opt-in or opt-out. So we can
exclude functions that .
Side thought... why a #switch library? What happened to the old
{{Foo/{{{1}}}|...}} trick?
~Daniel Friesen (Dantman, Nadir-Seen-Fire) [http://daniel.friesen.name]
I would have thought this could be done automatically, by designating
templates as being pure or impure (in the sense of pure and impure
functions) -- something which could be done recursively all the way down
to basic parser functions, magic words, etc., which would have to be
designated pure or impure by hand as part of the software implementation.
-- Neil
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Re: [Wikitech-l] A question about templates parsing and caching
On 11/04/11 06:32, Platonides wrote:
Roan Kattouw wrote:
2011/4/9 Platonidesplatoni...@gmail.com:
Yes. Calling a template twice will only fetch the text once, won't
increase the 'used templates' counter...
Preprocessing of wikitext over a threshold is cached serialized (it's
easier to reprocess if it's too small).
To clarify: there's an in-process cache, like Brion said, so a
template that is used twice on the same page is only fetched and
preprocessed once. However, this only applies to templates called with
no parameters. If the template is passed parameters, this in-process
cache won't be used, even if the same set of parameters is used twice.
I don't think so. The preprocess-to-tree is always the same, regardless
of the parameters, and it is always used. It is the expansion where
parameter change. I don't see that cache for parameterless templates,
maybe it's the mTplExpandCache?
The stages are basically preprocessToObj() - expand() - internalParse().
preprocessToObj() is the parsing stage of the preprocessor. It is fast
and easily cachable. It produces an object-based representation of the
parse tree of the text of single article or template. This object
representation is stored in a cache ($wgParser-mTplDomCache) which
exists for the duration of a single article parse operation. It
depends only on a single input string, it does not expand templates.
There is a persistent cache which stores the result of
preprocessToObj() across multiple requests, however this provides only
a small benefit.
expand() is slow. Its function is to take the parse tree of an
article, and to expand the template invocations and parser functions
that it sees to produce preprocessed wikitext.
There is a cache of the expand() step which persists for the duration
of a single parse operation ($wgParser-mTplExpandCache), but it only
operates on template invocations with no arguments, like {{!}}. It's
possible in theory to cache the expand() results for templates with
arguments, but I didn't do it because it looked like it would be
difficult to efficiently hash the parse tree of the arguments in order
to retrieve the correct entry from the cache. This would be a good
project for future development work.
I think it's fair to constrain parser functions to require that they
return the same result for the same arguments, during a single parse
operation. That's all you need to do to have an effective expand() cache.
However, the benefit would be limited due to the dominance of
infoboxes and navboxes which appear only once in each article. It's
not guaranteed that the result of expand() will be the same when done
at different times or in different articles.
internalParse() takes preprocessed wikitext and produces HTML. The
final output is cached by the parser cache.
-- Tim Starling
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Re: [Wikitech-l] A question about templates parsing and caching
On 11-04-10 06:13 PM, Tim Starling wrote:
[...]
I think it's fair to constrain parser functions to require that they
return the same result for the same arguments, during a single parse
operation. That's all you need to do to have an effective expand() cache.
[...]
-- Tim Starling
That /might/ work nicely for #ask.
However Counter, ArrayExtension, Variables, Random, etc... won't play
nicely with that.
Perhaps a way for parser functions to opt-in or opt-out. So we can
exclude functions that .
Side thought... why a #switch library? What happened to the old
{{Foo/{{{1}}}|...}} trick?
~Daniel Friesen (Dantman, Nadir-Seen-Fire) [http://daniel.friesen.name]
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