Wikidata/Archive/Describing wikidata structures

Depending on how the Wikidata proposal is implemented, there may be a need for a format to describe the structure of wikidata tables. This page proposes a format that uses the pipe syntax wikicode. Obviously, the wikidata implementation would ignore attributes (like border="1"), table headings (beginning with |+), and row/column headings (beginning with !).

Examples

Movie

This mock-up shows what editing an instance of the structure on the left might look like

Year	year
Tagline	line
Plot summary	multiline
Cast	substructure-array	Actor line autolink Character line autolink
Runtime	number	minute
Country	line	autolink
Color	enumeration	Technicolor B&W

Element

Symbol	line
Atomic number	number
Chemical series	enumeration	Alkali metals Alkaline earth metals Lanthanides Actinides Transition metals Poor metals Metalloids Nonmetals Halogens Noble gases
Atomic mass	number	g/mol
Electron configuration	line
Electrons per shell	number
Phase	enumeration	Solid Liquid Gas
Density at 0°C	number	g/L
Melting point (at 2.5 MPa)	number	K
Boiling point (at 2.5 MPa)	number	K
Heat of fusion	number	kl/mol
Heat of vaporization	number	kl/mol
Heat capacity (at 25 °C)	number	J/(mol·K)
Crystal structure	enumeration	triclinic monoclinic orthorhombic hexagonal rhombohedral tetragonal cubic
Atomic radius	number	pm
Covalent radius	number	pm
Van der Waals radius	number	pm
Unstable isotopes	substructure-array	Atomic mass number g/mol Natural abundance number Half life number y Decay mode enumeration alpha decay β− decay β+ decay electron capture proton emission spontaneous fission Decay energy number MeV Decay product line

Software

Developer	line
Latest version	line
Release date of latest version	date
OS	enumeration-other	Cross-platform Linux FreeBSD NetBSD OpenBSD Mac OS 8/9 Mac OS X Windows
Genre	enumeration-other	Antivirus Audio editor Automation CD copying software Database management system Emulation
License	enumeration-other	BSD License GPL LGPL Sun Public License Zope Public License
Website	url

Star

Mass	number	kg
Radius	number	km
Luminosity	number	L☉
Surface temperature	number	K
Age	number	y
Notable features	multiline
Spectral type	enumeration	O B A F G K M

Type keywords

The middle column in the examples above contains a keyword that describe the datatype of the field.

Table of keywords

Keyword	Meaning
number	The third column of the structure description contains the units of this number, if applicable.
year	Like a number, except it's autolinked and has no unit information
line	The field should be edited with an <input type="text">. If the third column contains autolink, then when the field is automatically linked. Otherwise the third column should be empty.
url	Like the line type, but it is automatically linked as an external link.
multiline	The field should be edited with a <textarea>...</textarea>
enumeration	The third column of the structure description is a sub-table where each row is a possible value for the enumeration. When editing an instance of this structure, the user is presented with a combo-box of the possible values.
enumeration-other	Like an enumeration, except there's an Other option in the combo box, and a text field next to the combo box for entering something that isn't in the enumeration.
substructure-array	The third column is a nested structure description. The only restrictions on the structure description are that it can't have fields of type multiline or substructure-array, and it can't have more than 10 fields. Consider the example of the Movie datastructure. It has a field called cast that is of type substructure-array. The substructure has two fields--Actor and Character--both of type line. This can store a mapping of actors to characters.
boolean	A check box is used to edit this field.
date	A day/month/year, but not a time

PHP Functions

Table Parser

This function takes a string containing wikicode as an argument, and returns a 2-dimensional array of strings representing the first table found in the wikicode.

function wikidata_parse_table($code) {
       $lines = preg_split('/\\r?\\n/', $code);
       $level = 0;
       $array = array();
       $row = 0;
       $col = -1;
       foreach ($lines as $line) {
               if (preg_match('/^{\\|/', $line)) {
                       $level++;
                       if ($level > 1 && $col > -1) {
                               $array[$row][$col] .= "\n" . $line;
                       }
               } else if (preg_match('/^\\|-/', $line)) {
                       if ($level == 1) {
                               $row++;
                               $col = -1;
                       } else if ($level > 1 && $col > -1) {
                               $array[$row][$col] .= "\n" . $line;
                       }
               } else if (preg_match('/^\\|}/', $line)) {
                       if ($level > 1 && $col > -1) {
                               $array[$row][$col] .= "\n" . $line;
                       }
                       $level--;
                       if ($level == 0) {
                               return $array;
                       }
               } else if ($level == 1
                       && preg_match('/^\\|(.*)$/', $line, $matches)) {
                       $columns = explode("||", $matches[1]);
                       foreach ($columns as $column) {
                               $col++;
                               $array[$row][$col] = $column;
                       }
               } else if ($level > 1 && $col > -1) {
                       $array[$row][$col] .= "\n" . $line;
               }
       }
       return NULL;
}