[JimmXinu]

Well, I set out to make a simple way to include or exclude metadata values. But like most of my projects, it quickly spiraled into something considerably more complex than I'd first intended.

This is very much a test version because I'm not convinced this should even be done, let alone done this way.

And the explanation is crazy long:

Spoiler:

Let's start with some simple cases first.

UPDATE May 5, 2014 - Remove obsolete beta versions

'Include' in this case really means 'include ONLY these.' If a
metadata type has lines in include, only those values will be kept,
all others are discarded.

UPDATE May 5, 2014 - Remove obsolete beta versions

(Note that the separator is '==', which is different than in
replace_metadata.)

## in stories from site dramione.org, only use these 4 characters, all
## others will be omitted.  Because only characters are listed, only
## characters will be effected.
[dramione.org]
include_metadata_pre:
 characters==Draco Malfoy
 characters==Hermione Granger
 characters==Harry Potter
 characters==Ron Weasley

## in stories from site www.fimfiction.net, only keep these 2
## characters, all others will be omitted.  And only Comedy and
## Adventure genres will be used--all other genres will be omitted.
## All other metadata will be as usual.
[www.fimfiction.net]
include_metadata_pre:
 characters==Twilight Sparkle
 characters==Rainbow Dash
 genre==Comedy
 genre==Adventure

If, on the other hand, you want to keep most values, and want to
exclude only certain values you use 'exclude' instead. (The =~ will
be explained next.)

## in stories from site thequidditchpitch.org, exclude warnings 'Minor
## Fluff', AU and anything with 'Contains Spoiler' in it; and the genre
## PWP.  All other values will be kept.
[thequidditchpitch.org]
exclude_metadata_pre:
 warnings==Minor Fluff
 warnings==Alternate Universe
 warnings=~Contains Spoiler
 genre==PWP

In both include and exclude, you can use regular expressions(regex)
instead of simple strings by using '=~' for the separator.

## in stories from site buffynfaith.net, only include ships with Buffy
## in them, even if spelled with a lower case 'b'.
[buffynfaith.net]
include_metadata_pre:
 ships=~[Bb]uffy

## in stories from site www.fimfiction.net, only use these 2
## characters, all others will be omitted.  All other metadata will be
## as usual.
[www.fimfiction.net]
include_metadata_pre:
 characters=~^(Twilight Sparkle|Rainbow Dash)$

## exclude the Mane Six or Main 6 or variation.
exclude_metadata_pre:
 characters=~(Mane|Main) (Six|6)

But what happens when you're using a site that has more than one
category of story and you only want to affect one fandom at a time?
You can use conditionals similar to replace_metadata. And in
include/exclude, conditionals can be either exact string(==) or
regex(=~) too.

While an include line for say 'characters' without a conditional means
only characters explicitly matched by include lines will be kept, an
include line with a conditional only effects stories that meet the
conditional.

## in stories from site archiveofourown.org, when category contains
## 'The Hobbit', only include these three characters.  All other
## stories will continue to have full characters.
[archiveofourown.org]
include_metadata_pre:
 characters==Bilbo&&category==The Hobbit
 characters==Samwise&&category==The Hobbit
 characters==Gandalf&&category==The Hobbit

## still on archiveofourown.org, exclude any character with Bucky in
## it, but only for Marvel, Captain America & Avengers
exclude_metadata_pre:
 characters=~Bucky&&category=~(Marvel|Captain America|Avengers)

Note that include is applied first, then exclude.

## in stories from site buffynfaith.net, only include ships with Buffy
## in them, even if spelled with a lower case 'b'.
[buffynfaith.net]
include_metadata_pre:
 ships=~[Bb]uffy

## But exclude any Buffy/Dawn.
exclude_metadata_pre:
 ships=~[Bb]uffy/Dawn

You may have noticed that all the examples so far ended in '_pre'.
That's because all of these were applied *before* replace_metadata is
applied. You can also use include_metadata_post and
exclude_metadata_post to filter *after* replace_metadata is applied.

[default]
replace_metadata:
 ... tons of code to tweak metadata to your exacting standards
 ... and normalize all the character names juuuust right

## Now make sure that only characters that start with your corrected
## formatting are included.
include_metadata_post:
 characters=~^(Books|Anime|Movies)\.

Now one last twist. In addition to == and =~ to match exact strings
and regex, you can also use != and !~ to *negate* the match. Much of
what you can do with negated matches can be done by include/exclude,
but some things can't. Don't go crazy with negated matches--Figuring
out which to use when and why can be quite complicated.

[www.fimfiction.net]
## These two on their own are functionally equivalent: exclude
## 'Twilight Sparkle' in characters
include_metadata_pre:
 characters!=Twilight Sparkle

exclude_metadata_pre:
 characters==Twilight Sparkle

## But these two are *not*:

## excludes these two as expected.
exclude_metadata_pre:
 characters==Twilight Sparkle
 characters==Rainbow Dash

## includes all characters because Rainbow Dash matches != Twilight
## Sparkle and Twilight Sparkle matches != Rainbow Dash.  So both
## match an include line and are kept.
include_metadata_pre:
 characters!=Twilight Sparkle
 characters!=Rainbow Dash

Realistically, I expect negated matches to be more useful in the
conditionals.

[fanfiction.net]
## Exclude Harry Porter, Harry Pearson, etc from other fandoms.
exclude_metadata_pre:
 characters==Harry P.&&category!=Harry Potter

And finally, if you need a trailing space in a string or regex, you can use \s and
FFDL will convert it to a space.

Everybody, but Jade & FireDancer especially, let me know what you think.