Class: Infoboxer::Tree::Template

Inherits:
Compound show all
Includes:
Linkable
Defined in:
lib/infoboxer/tree/template.rb

Overview

Represents MediaWiki template.

Template is basically a thing with name, some variables and their values. When pages are displayed in browser, templates are rendered in something different by wiki engine; yet, when extracting information with Infoboxer, you are working with original templates.

It requires some mastering and understanding, yet allows to do very poweful things. There are many kinds of them, from pure formatting-related (which are typically not more than small bells and whistles for page outlook, and should be rendered as a text) to very information-heavy ones, like infoboxes, from which Infoboxer borrows its name!

Basically, for information extraction from template you'll list its #variables, and then use #fetch method (and its variants: #fetch_hash/##fetch_date) to extract their values.

On variables naming

MediaWiki templates can contain named and unnamed variables. Example:

{{birth date and age|1953|2|19|df=y}}

This is template with name "birth date and age", three unnamed variables with values "1953", "2" and "19", and one named variable with name "df" and value "y".

For consistency, Infoboxer treats unnamed variables exactly the same way MediaWiki does: they considered to have numeric names, which are started from 1 and stored as a strings. So, for template shown above, the following is correct:

template.fetch('1').text == '1953'
template.fetch('2').text == '2'
template.fetch('3').text == '19'
template.fetch('df').text == 'y'

Note also, that named variables with simple text values are duplicated as a template node Node#params, so, the following is correct also:

template.params['df'] == 'y'
template.params.has_key?('1') == false

For more advanced topics, like subclassing templates by names and converting them to inline text, please read Infoboxer::Templates module's documentation.

Direct Known Subclasses

Infoboxer::Templates::Base

Instance Attribute Summary collapse

Attributes inherited from Compound

#children

Attributes inherited from Node

#params, #parent

Instance Method Summary collapse

Methods included from Linkable

#url

Methods inherited from Compound

#index_of, #text

Methods inherited from Node

#==, #children, coder, def_readers, #index, #inspect, #next_siblings, #prev_siblings, #siblings, #text, #text_, #to_s

Methods included from Navigation::Sections::Node

#in_sections

Methods included from Navigation::Shortcuts::Node

#bold?, #categories, #external_links, #heading?, #headings, #images, #infoboxes, #italic?, #lists, #paragraphs, #tables, #templates, #wikilinks

Methods included from Navigation::Lookup::Node

#_lookup, #_lookup_children, #_lookup_next_siblings, #_lookup_parents, #_lookup_prev_siblings, #_lookup_siblings, #_matches?, #has_parent?, #lookup, #lookup_children, #lookup_next_siblings, #lookup_parents, #lookup_prev_siblings, #lookup_siblings, #matches?

Constructor Details

#initialize(name, variables = Nodes[]) ⇒ Template

Returns a new instance of Template.



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# File 'lib/infoboxer/tree/template.rb', line 108

def initialize(name, variables = Nodes[])
  super(Nodes[], extract_params(variables))
  @name  = name 
  @variables = Nodes[*variables].each{|v| v.parent = self}
end

Instance Attribute Details

#name ⇒ String (readonly)

Template name, designating its contents structure.

See also #url, which you can navigate to read template's definition (and, in Wikipedia and many other projects, its documentation).

Returns:

  • (String) 


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# File 'lib/infoboxer/tree/template.rb', line 99

def name
  @name
end

#variables ⇒ Nodes<Var> (readonly)

Template variables list.

See Var class to understand what you can do with them.

Returns:



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# File 'lib/infoboxer/tree/template.rb', line 106

def variables
  @variables
end

Instance Method Details

#fetch(*patterns) ⇒ Nodes<Var>

Fetches template variable(s) by name(s) or patterns.

Usage:

argentina.infobox.fetch('leader_title_1')   # => one Var node
argentina.infobox.fetch('leader_title_1',
                        'leader_name_1')    # => two Var nodes
argentina.infobox.fetch(/leader_title_\d+/) # => several Var nodes

Returns:



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# File 'lib/infoboxer/tree/template.rb', line 141

def fetch(*patterns)
  Nodes[*patterns.map{|p| variables.find(name: p)}.flatten]
end

#fetch_date(*patterns) ⇒ Date

Fetches date by list of variable names containing date components.

(Experimental, subject to change or enchance.)

Explanation: if you have template like

{{birth date and age|1953|2|19|df=y}}

...there is a short way to obtain date from it:

template.fetch_date('1', '2', '3') # => Date.new(1953,2,19)

Returns:

  • (Date) 


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# File 'lib/infoboxer/tree/template.rb', line 166

def fetch_date(*patterns)
  components = fetch(*patterns)
  components.pop while components.last.nil? && !components.empty?
  
  if components.empty?
    nil
  else
    Date.new(*components.map{|v| v.to_s.to_i})
  end
end

#fetch_hash(*patterns) ⇒ Hash<String => Var>

Fetches hash {name => variable}, by same patterns as #fetch.

Returns:

  • (Hash<String => Var>) 


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# File 'lib/infoboxer/tree/template.rb', line 148

def fetch_hash(*patterns)
  fetch(*patterns).map{|v| [v.name, v]}.to_h
end

#follow ⇒ MediaWiki::Page

Extracts template source and returns it parsed (or nil, if template not found).

NB: Infoboxer does NO variable substitution or other template evaluation actions. Moreover, it will almost certainly NOT parse template definitions correctly. You should use this method ONLY for "transclusion" templates (parts of content, which are included into other pages "as is").

Look for example at this page's source: each subtable about some region is just a transclusion of template. This can be processed like:

Infoboxer.wp.get('Tropical and subtropical coniferous forests').
  templates(name: /forests^/).
  follow.tables #.and_so_on

See also Linkable#follow for general notes on the following links.

Returns:




# File 'lib/infoboxer/tree/template.rb', line 179

#link ⇒ Object

Wikilink name of this template's source.



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# File 'lib/infoboxer/tree/template.rb', line 205

def link
  # FIXME: super-naive for now, doesn't thinks about subpages and stuff.
  "Template:#{name}"
end

#to_tree(level = 0) ⇒ Object

See Node#to_tree



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# File 'lib/infoboxer/tree/template.rb', line 115

def to_tree(level = 0)
  '  ' * level + "<#{descr}>\n" +
    variables.map{|var| var.to_tree(level+1)}.join
end

#unnamed_variables ⇒ Nodes<Var>

Returns list of template variables with numeric names (which are treated as "unnamed" variables by MediaWiki templates, see class docs for explanation).

Returns:



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# File 'lib/infoboxer/tree/template.rb', line 125

def unnamed_variables
  variables.find(name: /^\d+$/)
end