View source for Module:Adjacent stations/doc

{{High-use}}
{{Lua|Module:Yesno|Module:Arguments|Module:Color contrast|Module:Trim quotes}}
{{Module rating|protected}}
{{Sidebar Adjacent stations}}

This module implements {{tl|Adjacent stations}}, {{tl|Rail icon}}, {{tl|Rail color box}}, {{tl|Line link}}, {{tl|Station link}} and {{tl|Rail color}}. Please see those templates' pages for documentation on how to use those templates. (Instructions for the <code>convert</code> function of this module are in the {{tl|Adjacent stations}} documentation.)

The aforementioned templates rely on data stored in subpages for this module ([[Special:PrefixIndex/Module:Adjacent_stations/|list]]). For example, {{tl2|Rail icon|MTR}} generates {{Rail icon|MTR}} using [[Module:Adjacent stations/MTR]].

It is possible to create and edit data by following existing examples, but having some knowledge of Lua helps prevent mistakes. If you have programmed or used Lua before, you may like to skip the next subsection.

== Terms ==
{{for|a more comprehensive overview of Lua|:mw:Extension:Scribunto/Lua reference manual}}

* Lua has ''data types''. The ones relevant here are ''boolean'', ''string'', ''number'', and ''table''.
** A ''[[Boolean data type|boolean]]'' is either <code>true</code> or <code>false</code>.
** A ''string'' is text, stored as a list of characters. While Lua has several ways of indicating strings within code, in the Lua examples here, strings are indicated by enclosing text in double quotes (e.g. <code>"This is a string"</code>).
** A ''number'' is a numerical value, like <code>0.5</code> or <code>42</code>.
** A ''table'' is a structure that can contain other objects, including other tables.
*** An empty table looks like <code>{}</code> in the code.
*** Tables have ''keys'' and ''values'', which are typically of the structure <code>["<var>key</var>"] = <var>value</var></code>; each key–value pair is separated by a comma. All keys used here are strings or numbers.
*** <code>{"text", "more text"}</code> is equivalent to <code>{[1] = "text", [2] = "more text"}</code>.
* A ''variable'' can be defined using <code>local <var>variable_name</var> = <var>"value"</var>.</code>
* ''Whitespace'' is any tab, line break or other space. Whitespace doesn't matter in Lua, but all examples here except for those inline with text are neatly indented for readability, with separate table keys on separate lines.
* A ''return statement'' (e.g. <code>return <var>variable_name</var></code>) causes a function to exit and reports the value of <code><var>variable_name</var></code>. The "function" here is the code in the main module calling the subpage, and the <code><var>variable_name</var></code> should be the data table.

== Basic structure ==
Two modules are demonstrated below:
{| class="wikitable"
|-
| [[Module:Adjacent stations/blank|Blank]] || {{syntaxhighlight|lang=lua|{{Module:Adjacent stations/blank}}}}
|-
| [[Module:Adjacent stations/Kaohsiung Rapid Transit|Example]] || {{syntaxhighlight|lang=lua|{{Module:Adjacent stations/Kaohsiung Rapid Transit}}}}
|}
The example module is [[Module:Adjacent stations/Kaohsiung Rapid Transit]].
* The two required table entries are "station format" and "lines". The former is a table with data to form links to station articles, and the latter is a table containing a table for each line.
* "system title" is the text in the middle cell of the table header row.
* "station format" defines the default name format for station articles and exceptions. The first variable ("%1 metro station") is the default. Exceptions are listed as key–value pairs (e.g. "Zuoying"–"Zuoying HSR station"), where the key is the input name. The module displays the input name and links to the article with the formatted name, replacing "%1" with the input. Alternatively, the full wikilink and be entered. This can be used to have the display be different from the input.
* "lines" is where the lines are listed. The names here are used internally and not displayed, so choose a concise one.
* "line title" is the text displayed in the middle of each row indicating the line; "left terminus" is the default station name for the left side terminus, and "right terminus" is the default station name for the right side terminus.
* Each "color" entry is the colour of the line.

Below is [[Module:Adjacent stations/Taiwan High Speed Rail]]:
{{syntaxhighlight|lang=lua|{{Module:Adjacent stations/Taiwan High Speed Rail}}}}
* <var>x</var> (defined in the first line) is a string used for formatting the station name. The variable <var>x</var> is used inside the "station format" table for the three articles where the title ends in "station" instead of "HSR station". This practice is optional but helpful when many articles fit a second pattern.
* The module recognises a virtual line named <code>["_default"]</code>. The title and colour of this line is used for all lines unless overridden. Parameters are used in the absence of a specified <code>line=</code> in transclusion.

== Hierarchy and list of parameters ==
# The first layer of the table is data for the entire system, as well as output options.
# Under the system table is the list of lines.
# The third layer is data for a given line.
# Each line can have 'types'. This can be either types of services or branches of the line.
# The fifth layer is data for a given type.

If not specified, all keys and values are strings.

=== Main layer (1) ===
{| class="wikitable"
|+
!Parameter
!Type
!Used in {{Tl|Adjacent stations}}
!Description
|-
|<code>["lang"]</code>
|String
|{{Yes}}
|Values are <code>"en-US"</code> and <code>"en-GB"</code>. If not set, <code>"en-GB"</code> is assumed.
|-
|<code>["system title"]</code>
|String
|{{Yes}}
|Text in the middle cell of the header.
|-
|<code>["system icon"]</code>
|String
|{{Yes}}
|Image used in the middle cell of the {{tl|Adjacent stations}} header and by {{tl|Rail icon}}.
|-
|<code>["system icon format"]</code>
|String
|{{No}}
|Icon type, used by {{tl|Rail icon}}. If specified and not <code>"image"</code>, the value is passed to the function that implements {{tl|Rail color box}}.
|-
|<code>["system color"]</code>
|String
|{{No}}
|RGB hex triplet (three or six characters, like <code>"BE2D2C"</code> or <code>"039"</code>). Can be called by using only one parameter in {{tl|Rail color}}.
|-
|<code>["header stop noun"]</code>
|String
|{{Yes}}
|The noun after 'preceding' and 'following' in the left and right header cells. Default value is <code>"station"</code>.
|-
|<code>["name format"]</code>
|String
|{{No}}
|CSS for the header of {{tl|Infobox station}} and anything else using the <code>style</code> function with {{para|1|header}}. Values can be strings or nested tables, with the first level being for the line (whatever's in {{para|style2}} of {{tl|Infobox station}}). The second level is currently unused. The first entry in a nested table with no key (i.e. with key <code>1</code>) is the default.
|-
|<code>["header background color"]</code>
|String
|{{No}}
|RGB hex triplet for {{tl|Infobox station}} subheaders and anything else using the <code>style</code> function with {{para|1|subheader}}. By default, it is a light gray. Values can be strings or nested tables, like those for <code>"name format"</code>.
|-
|<code>["header text color"]</code>
|String
|{{No}}
|RGB hex triplet for {{tl|Infobox station}} subheaders and anything else using the <code>style</code> function with {{para|1|subheader}}. By default, it is calculated based on the header background color. Values can be strings or nested tables, like those for <code>["name format"]</code>.
|-
|<code>["station format"]</code>
|Table or string
|{{Yes}}
|Table containing station format strings. The first entry without a specified key (i.e. with the key being the number <code>1</code>) is the default, and all other entries must have keys corresponding to the input. Format strings without wikilink brackets are converted to links, with the input (usually the station name) used as the displayed text. Tables can be nested within this table to indicate options based on the line and line type passed to this template.

<code>%1</code>, <code>%2</code> and <code>%3</code> can be used in all strings regardless of the level of nesting to be replaced respectively by the station input, the line input (after alias replacement) and the type input (after alias replacement).
|-
|<code>["lines"]</code>
|Table
|{{Yes}}
|Data table containing line tables.
|-
|<code>["aliases"]</code>
|Table
|{{Yes}}
|Table containing aliases (as table keys) for lines (as values). All keys are lowercase, as the input is treated as case-insensitive by being lower-cased.
|}

=== Station format table (2) ===
{| class="wikitable"
|+
!Parameter
!Type
!Used in {{Tl|Adjacent stations}}
!Description
|-
|<code>[1]</code>
|String
|{{Yes}}
|Default format.
|-
|<code>["''non-default station name''"]</code>
|String or table
|{{Yes}}
|Format for a non-default station, or line-specific format table.
|}

=== Line-specific format table (3) ===
{| class="wikitable"
|+
!Parameter
!Type
!Used in {{Tl|Adjacent stations}}
!Description
|-
|<code>[1]</code>
|String
|{{Yes}}
|Default format.
|-
|<code>["''line name''"]</code>
|String or table
|{{Yes}}
|Format for a non-default station, or type-specific format table.
|}

=== Type-specific format table (4) ===
{| class="wikitable"
|+
!Parameter
!Type
!Used in {{Tl|Adjacent stations}}
!Description
|-
|<code>[1]</code>
|String
|{{Yes}}
|Default format.
|-
|<code>["''type name''"]</code>
|String
|{{Yes}}
|Format for a non-default station.
|}

=== Line table (3) ===
A virtual line named <code>["_default"]</code> can be added to set default values for all lines. Currently, this is available for three parameters.
{| class="wikitable"
!Parameter
!Type
!Used in {{Tl|Adjacent stations}}
!Description
|-
|<code>["title"]</code>
|String
|{{Yes}}
|The text displayed in the middle cell, typically a link to the line's article. If not specified, then the data in <code>["_default"]</code> is used (<code>%1</code> in the default value is replaced by the input after alias replacement).
|-
|<code>["short name"]</code>
|String
|{{No}}
|Abbreviated line name used by {{tl|Rail color box}}.
|-
|<code>["icon"]</code>
|String
|{{No}}
|Image used by {{tl|Rail icon}}. If not specified, then the data in <code>["_default"]</code> is used (<code>%1</code> in the default value is replaced by the input after alias replacement).
|-
|<code>["icon format"]</code>
|String
|{{No}}
|Icon type used by {{tl|Rail icon}}. If specified and not <code>"image"</code>, the value is passed to the function that implements {{tl|Rail color box}}.
|-
|<code>["color"]</code>
|String
|{{Yes}}
|RGB hex triplet. Lines fall back to the <code>["_default"]</code> colour (if any) or the system's colour if they themselves do not have one; types fall back to the line's colour (if any), to the <code>["_default"]</code> colour (if any) or to the system's colour. This colour is used in the second and fourth columns of {{tl|Adjacent stations}}, and by {{tl|Rail color box}} and {{tl|Rail icon}} as the emphasised colour. By default, if a type and its line both have a colour, then the line's colour will be treated as the background colour (see next section) for the line name in the middle cell. This can be turned off by setting the type's background colour to <code>""</code> or <code>"transparent"</code>.
|-
|<code>["background color"]</code> 
|String
|{{Yes}}
|RGB hex triplet (three or six characters). This colour is optional and is only displayed behind the line name in the middle cell. The module adds transparency so that all text displayed over the background is legible.
|-
|<code>["border color"]</code>
|String
|{{No}}
|RGB hex triplet used by {{tl|Rail color box}}.
|-
|<code>["text color"]</code>
|String
|{{No}}
|RGB hex triplet used by {{tl|Rail color box}}.
|-
|<code>["left terminus"]</code>
|String
|{{Yes}}
|The station which is usually the left terminus of the line. If there are multiple stations by default, the value should be a table containing numbered values (e.g. <code>["left terminus"] = {"Chesham", "Amersham"}</code>). The key <code>["via"]</code> in that table can be used to append 'via' and the value's station link.
|-
|<code>["right terminus"]</code>
|String
|{{Yes}}
|The station which is usually the right terminus of the line; behaves like <code>["left terminus"]</code>.
|-
|<code>["note-mid"]</code>
|String
|{{Yes}}
|Default small text below line and type names. Overridden by {{para|note-mid}} in transclusion.
|-
|<code>["circular"]</code>
|Boolean
|{{Yes}}
|If the value is <code>true</code> then the termini will display without 'toward'/'towards'. May be overridden by type.
|-
|<code>["oneway-left"]</code> 
|Boolean
|{{Yes}}
|If the value is <code>true</code> then 'One-way operation' will display instead of the left terminus. 
|-
|<code>["oneway-right"]</code>
|Boolean
|{{Yes}}
|Right counterpart of oneway-left.
|-
|<code>["types"]</code>
|Table
|{{Yes}}
|Table containing the line type tables.
|}

=== Type table (5) ===
{| class="wikitable"
!Parameter
!Type
!Used in {{Tl|Adjacent stations}}
!Description
|-
|<code>["title"]</code>
|String
|{{Yes}}
|The name of the line type. In {{tl|Adjacent stations}}, this is displayed as normal-sized text below the line name in the middle cell; in {{tl|Rail color box}}, for some options this is displayed after the line name, separated from it by a spaced [[en dash]] (this is also used for the nonstop text). To avoid displaying a type name, set this to <code>""</code>.
|-
|<code>["short name"]</code>
|String
|{{No}}
|Abbreviated line name used by {{tl|Rail color box}}.
|-
|<code>["icon"]</code>
|String
|{{No}}
|Image used by {{tl|Rail icon}}.
|-
|<code>["icon format"]</code>
|String
|{{No}}
|Icon type used by {{tl|Rail icon}}. If specified and not <code>"image"</code>, the value is passed to the function that implements {{tl|Rail color box}}.
|-
|<code>["color"]</code>
|String
|{{Yes}}
|RGB hex triplet. Lines fall back to the <code>["_default"]</code> colour (if any) or the system's colour if they themselves do not have one; types fall back to the line's colour (if any), to the <code>["_default"]</code> colour (if any) or to the system's colour. This colour is used in the second and fourth columns of {{tl|Adjacent stations}}, and by {{tl|Rail color box}} and {{tl|Rail icon}} as the emphasised colour. By default, if a type and its line both have a colour, then the line's colour will be treated as the background colour (see next section) for the line name in the middle cell. This can be turned off by setting the type's background colour to <code>""</code> or <code>"transparent"</code>.
|-
|<code>["background color"]</code> 
|String
|{{Yes}}
|RGB hex triplet (three or six characters). This colour is optional and is only displayed behind the line name in the middle cell. The module adds transparency so that all text displayed over the background is legible.
|-
|<code>["border color"]</code>
|String
|{{No}}
|RGB hex triplet used by {{tl|Rail color box}}.
|-
|<code>["text color"]</code>
|String
|{{No}}
|RGB hex triplet used by {{tl|Rail color box}}.
|-
|<code>["left terminus"]</code>
|String
|{{Yes}}
|The station which is usually the left terminus of the line. Overrides line terminus. If there are multiple stations by default, the value should be a table containing numbered values (e.g. <code>["left terminus"] = {"Chesham", "Amersham"}</code>). The key <code>["via"]</code> in that table can be used to append 'via' and the value's station link.
|-
|<code>["right terminus"]</code>
|String
|{{Yes}}
|The station which is usually the right terminus of the line; behaves like <code>["left terminus"]</code>.
|-
|<code>["note-mid"]</code>
|String
|{{Yes}}
|Default small text below line and type names. Overridden by {{para|note-mid}} in transclusion.
|-
|<code>["circular"]</code>
|Boolean
|{{Yes}}
|If the value is <code>true</code> then the termini will display without 'toward'/'towards'.
<!-- Types currently do not have these parameters. However, it could make sense to add them if the need arises.
|-
|<code>["oneway-left"]</code> 
|Boolean
|{{Yes}}
|If the value is <code>true</code> then 'One-way operation' will display instead of the left terminus. 
|-
|<code>["oneway-right"]</code>
|Boolean
|{{Yes}}
|Right counterpart of oneway-left.
-->
|}

== For editors ==
=== Disambiguating stations ===
Station links are generated using the <code>station format</code> part of the data module. Each data module defines a default case and then exceptions, if necessary. <code>Station format</code> is an array, similar to a switch with cases. Take [[Module:Adjacent stations/Incheon Subway]], shown below:

{{syntaxhighlight|lang=lua|{{Module:Adjacent stations/Incheon Subway}}}}

The default case is <code>"%1 station"</code>, listed first. The "%1" expands to whatever the passed name of the station is. "Bakchon" becomes [[Bakchon station]]. There are several exceptions. The two usual reasons for exceptions are disambiguation or presenting a name in a non-standard way. In this case, the [[Incheon Subway]] serves three stations whose names are disambiguated: [[Arts Center station (Incheon)]], [[Central Park station (Incheon)]], and [[Mansu station (Incheon)]]. This is handled by specifying a key for each station and supplying a different format. Since all three are disambiguated the same way, you can define a local variable at the top of the module:

{{syntaxhighlight|lang=lua|code=local incheon = "%1 station (Incheon)"}}

This can then be used with the exceptions:

{{syntaxhighlight|lang=lua|code=["Arts Center"] = incheon,}}

Were it written out, it would look like this:

{{syntaxhighlight|lang=lua|code=["Arts Center"] = "%1 station (Incheon)"}}

== For developers ==
Suggestions are welcomed on the talk page.

=== To-do list ===
* Convert more systems from {{tl|S-line}}, {{tl|rail line}}, {{tl|J-rserv}} and {{tl|J-route}}
* Make [[Module:Adjacent stations/example|an example module]] which contains all of the module's features, to avoid excessive examples in the documentation (maybe based on {{tl|Rdt demo}})
* Allow direct replacement of {{tl|Rail line}}?
* Before translation: figure out how to handle grammatical gender and inflection in various languages with the i18n table (e.g. [https://translate.google.com/#en/fi/towards%20Edgware%2C%20High%20Barnet%20or%20Mill%20Hill%20East%0Atowards%20Edgware%20via%20Charing%20Cross%0Atowards%20High%20Barnet%20via%20Charing%20Cross%0Athrough%20to%20the%20Piccadilly%20line%0Athrough%20to%20the%20route%20Q42%0Athrough%20to%20the%20Waterfront%20line%0AThe%20red%20route%20does%20not%20stop%20here%0AThe%20blue%20line%20does%20not%20stop%20here%0ALine%2014%20does%20not%20stop%20here%0AService%2014%20does%20not%20stop%20here%0ARed%20line%20does%20not%20stop%20here%0ABlue%20route%20does%20not%20stop%20here these phrases])
* Allow inline sources to be added
* Figure out Wikidata integration (require sources on Wikidata end) : 
*:should be doable with P197, P5051, P1192 and P81. [[User:Bouzinac|Bouzinac]] ([[User talk:Bouzinac|talk]]) 09:17, 3 December 2021 (UTC)
* Add a short list of changes from {{tl|S-line}}, for the convenience of the many editors who have used it in the last 11 years
** changes in function (new structure, data inside module, circular and branch functionality changed, replacement of manual cell merging…)
** parameter name changes (-left and -right, mostly – search {{tl|S-line}} for {{(((}}, maybe with the TemplateData generator, to make a list)

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