The module offers elegant shortcuts to non variadic templates as well. Outside templates it has virtually no applications; hence, if you plan to make experiments, make sure to do them from within a template, or you will not be able to see much (you can use {{Template sandbox}} for that). Under ./testcases you can find helper templates that can be specifically used for testing the module's capabilities in flexible ways. Finally, under ./doc/examples you can find some of the examples shown in this documentation page.

 Note: In case your template uses {{#invoke:params}}, please add {{lua|Module:Params}} to its documentation page, so that if breaking changes will be introduced in the future the template will be easily traceable without performing an “in source” search.

Please, do not edit this module without having done extensive testing in the module's sandbox first.

Among the possibilities that the module offers there is that of performing a series of actions after novel arguments have been concatenated to templates' incoming parameters. As this makes it necessary to keep the argument slots clean from interference, instead of named arguments in order to specify options this module uses piping functions (i.e. functions that expect to be piped instead of returning to the caller), or modifiers. This creates a syntax similar to the following example:

{{#invoke:params|[modifier]|[...]|[modifier]|[...]|function|[...]}}

For instance, as the name suggests, the list function lists the parameters wherewith a template was called. By default it does not add delimiters, but returns an indistinct blob of text in which keys and values are sticked to each other. However, by using the setting modifier, we are able to declare a key-value delimiter (p) and an iteration delimiter (i). And so, if we imagined a template named {{example template}} containing the following wikitext,

{{#invoke:params|setting|i/p|<br />|: |list}}

and such template were called with the following arguments,

the following result would be produced:

Beast of Bodmin: A large feline inhabiting Bodmin Moor
Morgawr: A sea serpent
Owlman: A giant owl-like creature

We can also do more sophisticated things; for instance, by exploiting the possibility to set a header (h) and a footer (f), we can transform the previous code into a generator of definition lists,

{{#invoke:params|setting|h/p/i/f|<dl><dt>|</dt><dd>|</dd><dt>|</dd></dl>|list}}

thus yielding:

Beast of Bodmin

A large feline inhabiting Bodmin Moor

Morgawr

A sea serpent

Owlman

A giant owl-like creature

By placing the with_name_matching modifier before the list function we will be able to filter some parameters out – such as, for instance, all parameter names that do not end with an “n”:

{{#invoke:params|with_name_matching|n$|setting|h/p/i/f|<dl><dt>|</dt><dd>|</dd><dt>|</dd></dl>|list}}

Thus, the previous code will produce:

Beast of Bodmin

A large feline inhabiting Bodmin Moor

Owlman

A giant owl-like creature

This mechanism has the intrinsic advantage that it allows concatenating infinite modifiers. And so, in order to get the accurate result that we want to obtain we could write:

{{#invoke:params|non-sequential|with_name_matching|^B|with_name_matching|n$|with_value_matching|feline|setting|h/p/i/f|<dl><dt>|</dt><dd>|</dd><dt>|</dd></dl>|list}}

The two modifiers sequential and non-sequential refer to a technical jargon used in wikitext: given a parameter list, the subgroup of sequential parameters is constituted by the largest group of consecutive numerical parameters starting from 1= – this is known as the parameters' “sequence”. A parameter list that does not have a first parameter specified does not possess a sequence.

Here follows the list of functions. You might want to see also § Modifiers.

Brief

Return the name of the current template

Syntax

{{#invoke:params|self}}

This argumentless function guarantees that the name of the template invoking this module is shown, regardless if this is transcluded or not.

As a possible example, if a Wikipedia page named Page X contained only a transclusion of a template named {{foobar}}, and the latter contained the following wikitext,

{{#invoke:params|self}}

{{FULLPAGENAME}}

if we visited Template:Foobar we would see,

Template:Foobar

Template:Foobar

whereas if we visited Page X we would see:

Template:Foobar

Page X

Therefore by writing

{{#ifeq:{{#invoke:params|self}}|{{FULLPAGENAME}}
	|Page is not being transcluded
	|Page is being transcluded
}}

it is possible to understand whether a page is being transcluded or not. For most cases the <includeonly>...</includeonly> and <noinclude>...</noinclude> will offer a simpler solution, however there can be cases in which this becomes the way to go.

If Page X transcluded {{foobar 2}} and the latter were a redirect to {{foobar}}, we would still see

Template:Foobar

Page X

A typical use case of this function is that of providing stable links for editing transcluded templates. E.g.:

{{edit|{{#invoke:params|self}}|edit this template}}

Another possible use case is that of transcluding a subtemplate. E.g.:

{{{{#invoke:params|self}}/my subtemplate|foo|bar}}

Brief

Count the number of parameters wherewith a template was called

Syntax

{{#invoke:params|count}}

This function does not take arguments.

The number that this function yields depends on the modifiers that precede it. For instance, in a template that is called with both named and unnamed arguments,

{{#invoke:params|count}}

and

{{#invoke:params|sequential|count}}

will return different results.

Brief

Prepend positive numerical arguments to the current parameters, or impose non-numerical or negative numerical arguments, then propagate everything to a custom template

Syntax

{{#invoke:params|concat_and_call|template name|[prepend 1]|[prepend 2]|[...]|[prepend n]|[named item 1=value 1]|[...]|[named item n=value n]|[...]}}

For example, if our {{example template}} had the following code,

{{#invoke:params|concat_and_call|foobar|elbow|earth|room|7=classy|hello=not today}}

and were called with,

the following call to the {{foobar}} template would be performed:

By using the cutting modifier it is possible to impose numerical positive parameters instead of prepending them. For instance, the following code echoes all incoming parameters to {{my template}}, with the exception of |3=, which is replaced with hello world:

{{#invoke:params|cutting|3|0|concat_and_call|my template|{{{1|}}}|{{{2|}}}|hello world}}

If the numerical parameters to replace are a limited number, as in the example above, a better alternative might be that of using imposing.

If no other argument besides the template name are provided this function simply echoes the current parameters to another template.

 Note: All arguments passed to this function except the template name will not be trimmed of their leading and trailing spaces. The concat_and_call function name itself, however, will be trimmed of its surrounding spaces.

Brief

Prepend positive numerical arguments to the current parameters, or impose non-numerical or negative numerical arguments, then propagate everything to a custom module

Syntax

{{#invoke:params|concat_and_invoke|module name|function name|[prepend 1]|[prepend 2]|[...]|[prepend n]|[named item 1=value 1]|[...]|[named item n=value n]|[...]}}

Exactly like concat_and_call, but invokes a module instead of calling a template.

 Note: All arguments passed to this function except the module name and the function name will not be trimmed of their leading and trailing spaces. The concat_and_invoke function name itself, however, will be trimmed of its surrounding spaces.

Brief

Prepend positive numerical arguments to the current parameters, or impose non-numerical or negative numerical arguments, then propagate everything to a custom parser function

Syntax

{{#invoke:params|concat_and_magic|parser function|[prepend 1]|[prepend 2]|[...]|[prepend n]|[named item 1=value 1]|[...]|[named item n=value n]|[...]}}

Exactly like concat_and_call, but calls a parser function instead of a template.

 Note: All arguments passed to this function except the magic word will not be trimmed of their leading and trailing spaces. The concat_and_magic function name itself, however, will be trimmed of its surrounding spaces.

Brief

Get the value of a single parameter

Syntax

{{#invoke:params|value_of|parameter name}}

Without modifiers this function is similar to writing {{{parameter name|}}}. With modifiers, however, it allows reaching parameters that would be unreachable without knowing their number in advance. For instance, writing

{{#invoke:params|cutting|-2|0|value_of|1}}

will expand to the value of the second-last sequential parameter, independently of how many parameters the template was called with. If no matching parameter is found this function expands to nothing. A header (h), a footer (f), and a fallback text (n) can be declared via the setting modifier – the strings assigned to the key-value pair delimiter (p), the iteration delimiter (i) and the last iteration delimiter (l) will be ignored.

For instance, the {{If then show}} template could be rewritten as

{{#invoke:params|with_value_not_matching|^%s*$|setting|h/f/n|{{{3|}}}|{{{4|}}}|{{{2|}}}|value_of|1}}

Simplifying, the following wikitext expands to the first parameter that is not empty:

{{#invoke:params|with_value_not_matching||strict|squeezing|value_of|1}}

Whereas the following wikitext expands to the first parameter that is not blank (i.e. neither empty nor containing only whitespaces)

{{#invoke:params|with_value_not_matching|^%s*$|squeezing|value_of|1}}

Brief

List the template parameters (both their names and their values)

Syntax

{{#invoke:params|list}}

This function does not take arguments.

If the setting modifier was not placed earlier, this function will not add delimiters, but will return an indistinct blob of text in which keys and values are sticked to each other. A header (h), a key-value pair delimiter (p), an iteration delimiter (i), a last iteration delimiter (l), a footer (f), and a fallback text (n) can be declared via setting.

For example, the following code

{{#invoke:params|setting|h/i/p/f/n|'''Parameters passed:''' |); | (|)|'''No parameters were passed'''|list}}

will generate an output similar to the following.

Parameters passed: Owlman (A giant owl-like creature); Beast of Bodmin (A large feline inhabiting Bodmin Moor); Morgawr (A sea serpent)

Brief

List the values of the incoming parameters

Syntax

{{#invoke:params|list_values}}

This function does not take arguments.

The sequential modifier often accompanies this function. If the setting modifier was not placed earlier, this function will not add delimiters, but will return an indistinct blob of text in which values are sticked to each other. A header (h), an iteration delimiter (i), a last iteration delimiter (l), a footer (f), and a fallback text (n) can be declared via setting – the string assigned to the key-value pair delimiter (p) will be ignored.

For example, the following code

{{#invoke:params|setting|h/i/p/f/n|'''Parameters passed:''' |); | (|)|'''No parameters were passed'''|list_values}}

will generate an output similar to the following.

Values of parameters passed: A giant owl-like creature; A large feline inhabiting Bodmin Moor; A sea serpent.

Brief

For each parameter passed to the current template, call a custom template with at least two parameters (key and value)

Syntax

{{#invoke:params|call_for_each|template name|[append 1]|[append 2]|[...]|[append n]|[named param 1=value 1]|[...]|[named param n=value n]|[...] }}

Some functions are like shortcuts. The X_for_each|F functions are similar to mapping_by_X(ing)|F|(names_and_values|)list_values. The latter syntax (i.e. the modifier version) allows a values_and_names flag to invert the order from key-value to value-key.

All unnamed arguments following the template name will be placed after the key-value pair. Named arguments will be passed verbatim. A header (h), an iteration delimiter (i), a last iteration delimiter (l), a footer (f), and a fallback text (n) can be declared via the setting modifier – the string assigned to the key-value pair delimiter (p) will be ignored.

Calling a template for each key-value pair with

{{#invoke:params|sequential|call_for_each|foobar}}

will be different from writing

{{#invoke:params|sequential|for_each|{{foobar|$#|$@}}}}

In the first example each key-value pair will be passed to the {{foobar}} template, while in the second example the $# and $@ tokens will be expanded after the {{foobar}} template has been called. In most cases this will make no difference, however there are several situations where it will lead to nonsensical results.

 Note: All arguments passed to this function except the template name will not be trimmed of their leading and trailing spaces. The call_for_each function name itself, however, will be trimmed of its surrounding spaces.

Brief

For each parameter passed to the current template, invoke a custom module function with at least two arguments (key and value)

Syntax

{{#invoke:params|invoke_for_each|module name|module function|[append 1]|[append 2]|[...]|[append n]|[named param 1=value 1]|[...]|[named param n=value n]|[...]}}

Exactly like call_for_each, but invokes a module instead of calling a template.

Invoking a module function for each key-value pair with

{{#invoke:params|sequential|invoke_for_each|foobar|main}}

will be different from writing

{{#invoke:params|sequential|for_each|{{#invoke:foobar|main|$#|$@}}}}

In the first example each key-value pair will be passed to the {{#invoke:foobar|main}} module function, while in the second example the $# and $@ tokens will be expanded after the module function has been invoked. There might be cases in which this will make no difference, however there are several situations where it will lead to nonsensical results.

 Note: All arguments passed to this function except the module name and the function name will not be trimmed of their leading and trailing spaces. The invoke_for_each function name itself, however, will be trimmed of its surrounding spaces.

Brief

For each parameter passed to the current template, call a magic word with at least two arguments (key and value)

Syntax

{{#invoke:params|magic_for_each|parser function|[append 1]|[append 2]|[...]|[append n]|[named param 1=value 1]|[...]|[named param n=value n]|[...]}}

Exactly like call_for_each, but calls a parser function instead of a template.

 Note: All arguments passed to this function except the magic word will not be trimmed of their leading and trailing spaces. The magic_for_each function name itself, however, will be trimmed of its surrounding spaces.

Brief

For each parameter passed to the current template, call a custom template with at least one parameter (i.e. the parameter's value)

Syntax

{{#invoke:params|call_for_each_value|template name|[append 1]|[append 2]|[...]|[append n]|[named param 1=value 1]|[...]|[named param n=value n]|[...]}}

The sequential modifier often accompanies this function. All unnamed arguments following the template name will be appended after the value parameter. Named arguments will be passed verbatim. A header (h), an iteration delimiter (i), a last iteration delimiter (l), a footer (f), and a fallback text (n) can be declared via the setting modifier – the string assigned to the key-value pair delimiter (p) will be ignored.

For example, calling {{tl}} with each parameter can be done by writing

{{#invoke:params|sequential|setting|i|, |call_for_each_value|tl}}

This will be different from writing

{{#invoke:params|sequential|setting|i|, |for_each|{{tl|$@}}}}

In the first example each value will be passed to the {{tl}} template, while in the second example the $@ token will be expanded after the {{tl}} template has been called. Here this will make no difference, however there are several situations where it will lead to nonsensical results.

 Note: All arguments passed to this function except the template name will not be trimmed of their leading and trailing spaces. The call_for_each_value function name itself, however, will be trimmed of its surrounding spaces.

Brief

For each parameter passed to the current template, invoke a custom module function with at least one argument (i.e. the parameter's value)

Syntax

{{#invoke:params|invoke_for_each_value|module name|module function|[append 1]|[append 2]|[...]|[append n]|[named param 1=value 1]|[...]|[named param n=value n]|[...]}}

Exactly like call_for_each_value, but invokes a module instead of calling a template.

Invoking a module function for each value with

{{#invoke:params|sequential|invoke_for_each_value|foobar|main}}

will be different from writing

{{#invoke:params|sequential|for_each|{{#invoke:foobar|main|$@}}}}

In the first example each value will be passed to the {{#invoke:foobar|main}} module function, while in the second example the $@ token will be expanded after the module function has been invoked. There might be cases in which this will make no difference, however there are several situations where it will lead to nonsensical results.

 Note: All arguments passed to this function except the module name and the function name will not be trimmed of their leading and trailing spaces. The invoke_for_each_value function name itself, however, will be trimmed of its surrounding spaces.

Brief

For each parameter passed to the current template, call a magic word with at least one argument (i.e. the parameter's value)

Syntax

{{#invoke:params|magic_for_each_value|parser function|[append 1]|[append 2]|[...]|[append n]|[named param 1=value 1]|[...]|[named param n=value n]|[...]}}

Exactly like call_for_each_value, but calls a parser function instead of a template.

For example, if a template had the following code,

{{#invoke:params|sequential|setting|ih|&preloadparams%5b%5d{{=}}|magic_for_each_value|urlencode|QUERY}}

and were transcluded as {{example template|hello world|àèìòù|foobar}}, the {{urlencode:...|QUERY}} parser function would be called for each incoming parameter as first argument and with QUERY as second argument, and finally the returned text would be prefixed with &preloadparams%5b%5d=. This would generate,

&preloadparams%5b%5d=hello+world&preloadparams%5b%5d=%C3%A0%C3%A8%C3%AC%C3%B2%C3%B9&preloadparams%5b%5d=foo+bar

which can be used to allow the creation of pages with preloaded text and parameters.

 Note: All arguments passed to this function except the magic word will not be trimmed of their leading and trailing spaces. The magic_for_each_value function name itself, however, will be trimmed of its surrounding spaces.

Brief

Call a custom template for each group of parameters that have the same numerical suffix

Syntax

{{#invoke:params|call_for_each_value|template name|[append 1]|[append 2]|[...]|[append n]|[named param 1=value 1]|[...]|[named param n=value n]|[...] }}

The custom template will be repeatedly called with the numerical id of the group (i.e. the numerical suffix) as argument zero (i.e. {{{0}}}). This will be an empty string for the group of incoming parameters that do not have a numerical suffix. A hyphen before the numerical suffix will be interpreted as a minus sign (and therefore the group id will be treated as a negative number). Numerical incoming parameters will be treated as if their prefix is an empty string (these can be captured using {{{}}} or {{{|fallback text}}} in the callback template). Spaces between the prefix and the numerical suffix will be ignored (therefore writing |foobar123= will be identical to writing |foobar 123= – in case of collisions one of the two values will be discarded). In the unlikely scenario that the prefix is itself a number (e.g. |1 1=, |2 1=, etc.), if this is 0 or a negative number it will be decreased by one unit in order to leave the parameter zero undisturbed (so 0 will become -1, -1 will become -2, and so on – if needed, you can use ...|purging|0{1|... in the callback template to renormalize these numbers).

All unnamed arguments that follow the template name in the invocation of this module will appear as sequential parameters in each call. Named arguments will be passed verbatim. Both named and unnamed arguments passed to this function will be given precedence in case of collisions. Numerical argument names below 1 will be decreased by one unit (i.e. ...|call_for_each_group|example template|0=Hello world|... will become |-1=Hello world in the callback template – see above).

A header (h), an iteration delimiter (i), a last iteration delimiter (l), a footer (f), and a fallback text (n) can be declared via the setting modifier – the string assigned to the key-value pair delimiter (p) will be ignored.

If you are a module writer, you might recognize some distant similarities between this function and TableTools.affixNums.

For example, if a template named {{foobar}} contained the following code,

{{#invoke:params|reassorted|call_for_each_group|example template|hello|world|foo=bar}}

writing

{{foobar
	| 1 = Lorem
	| 2 = ipsum
	| bicycle-1 = dolor
	| bicycle1 = sit
	| boat1 = amet
	| car2 = consectetur
	| bicycle2 = adipiscing
	| other = elit
	| sunscreen = vestibulum
	| = ultricies
	| foo1 = neque nisl
}}

will be equivalent to writing

{{example template
	| 0 =
	| 1 = hello
	| 2 = world
	| = ultricies
	| foo = bar
	| other = elit
	| sunscreen = vestibulum
}}{{example template
	| 0 = -1
	| 1 = hello
	| 2 = world
	| bicycle = dolor
	| foo = bar
}}{{example template
	| 0 = 1
	| 1 = hello
	| 2 = world
	| = Lorem
	| bicycle = sit
	| boat = amet
	| foo = bar
}}{{example template
	| 0 = 2
	| 1 = hello
	| 2 = world
	| = ipsum
	| bicycle = adipiscing
	| car = consectetur
	| foo = bar
}}

The modifiers sequential, non-sequential, all_sorted and reassorted will affect what groups of parameters will be iterated, not what parameters will be grouped. Before calling this function you will likely want to reduce the list of parameters via one of the with_*_matching group of modifiers (for instance ...|with_name_matching|.%-%d+$|or|[^%-]%d+$|call_for_each_group|... leaves only the parameters in which both the prefix and the numerical suffix are not empty strings). The reassorted modifier often accompanies this function.

 Warning In writing templates, there is often the habit of signaling multilevel substitutions using the {{{|safesubst:}}} notation. This is a dangerous practice, because {{{|safesubst:}}} means “write the parameter with an empty name, otherwise write safesubst:”. Due to the fact that call_for_each_group can pass parameters with an empty name, a callback template should never use {{{|safesubst:}}} to notate multilevel substitutions, but should use instead safesubst:<noinclude />. Not following this advice can lead to bugs that are hard to debug.

At {{./doc/examples/list of authors}} you can find an example of how to use this function to list authors the same way {{Cite book}} does. For instance, writing

{{module:params/doc/examples/list of authors
	| last1 = Playfair
	| first1 = I. S. O.
	| author-link1 = Ian Stanley Ord Playfair
	| last2 = Stitt
	| first2 = G. M. S.
	| last3 = Molony
	| first3 = C. J. C.
	| last4 = Toomer
	| first4 = S. E.
}}

will generate

Playfair, I. S. O.; Stitt, G. M. S.; Molony, C. J. C. & Toomer, S. E.

See also {{./doc/examples/tablebox}} for ane example on how to exploit this function to create infoboxes.

 Note: All arguments passed to this function except the template name will not be trimmed of their leading and trailing spaces. The call_for_each_group function name itself, however, will be trimmed of its surrounding spaces.

Brief

For each parameter passed to the current template, expand all occurrences of $# and $@ within a given text as key and value respectively

Syntax

{{#invoke:params|for_each|wikitext}}

Example:

{{#invoke:params|for_each|Arg name: $#, Arg value: $@}}

The text returned by this function is not expanded further (currently this module does not offer an expand_for_each function). If you need wikitext expansion, use concat_and_call to propagate the incoming parameters altogether to the {{for nowiki}} template. Example:

{{#invoke:params|sequential|concat_and_call|for nowiki|[separator]|<nowiki>{{{i}}} is {{urlencode:{{{1}}}|QUERY}}</nowiki>}}

 Note: The argument passed to this function will not be trimmed of its leading and trailing spaces. The for_each function name itself, however, will be trimmed of its surrounding spaces.

The following are modifiers, i.e. functions that expect to be piped instead of returning to the caller. Each of them can be followed by either another modifier or a non-piping function. The actions that modifiers do are done sequentially, in the same order chosen during the invocation of this module. Some modifiers, however, after signaling their presence to the modifiers that might follow, add their action to the queue of actions that will be done last (e.g. sequential, non-sequential, all_sorted, reassorted).

Brief

(IN FUNCTIONS ONLY, DOES NOT AFFECT MODIFIERS) Reduce the parameter list to the subgroup of consecutive parameters that follow 1=

Syntax

{{#invoke:params|sequential|pipe function name}}

Example:

{{#invoke:params|sequential|count}}

This modifier does not take arguments besides the name of the function that will follow.

Using sequential together with non-sequential will generate an error.

 Note: Like non-sequential, the sequential modifier permanently marks a query. For instance, writing {{#invoke:params|sequential|with_name_not_matching|1|...}} will first mark the query as “sequential”, then will discard the first element from the sequence (leaving all the others intact). And so, no matter how many other parameters will be present, nothing will be shown.

Brief

(IN FUNCTIONS ONLY, DOES NOT AFFECT MODIFIERS) Reduce the parameter list by discarding the subgroup of consecutive parameters that follow 1=

Syntax

{{#invoke:params|non-sequential|pipe function name}}

Example:

{{#invoke:params|non-sequential|setting|ih/p|{{!}}|{{=}}|list}}

This modifier does not take arguments besides the name of the function that will follow.

Using non-sequential together with sequential will generate an error.

 Note: Like sequential, the non-sequential modifier permanently marks a query, and no matter what transformations will follow (see squeezing) the parameters' “sequence” will not be shown.

Brief

(IN FUNCTIONS ONLY, DOES NOT AFFECT MODIFIERS) When the time will come, all parameters will be dispatched sorted: first the numerical ones in ascending order, then the rest in natural order

Syntax

{{#invoke:params|all_sorted|pipe function name}}

 Note: This modifier sorts the way functions iterate across all parameters based on their names. If you want to sort sequential parameters based on their values, see sorting_sequential_values.

Example:

{{#invoke:params|all_sorted|setting|ih/p|{{!}}|{{=}}|list}}

This modifier does not take arguments besides the name of the function that will follow.

Normally only sequential parameters are dispatched sorted, whereas non-sequential ones are dispatched randomly. The all_sorted modifier ensures that nothing is left out of (natural) order. Attention must be paid to the fact that parameters whose name is a negative number will appear first. To avoid this the squeezing modifier can be used.

The all_sorted modifier only affects the way parameters are shown, but has no effects on functions that do not iterate or cannot impose an order, such as:

• count
• value_of
• concat_and_call
• concat_and_invoke
• concat_and_magic

 Note: The all_sorted modifier cannot be used with functions that propagate several parameters together in a single call, like concat_and_call, concat_and_invoke, and concat_and_magic, because during a call the order of arguments is always lost. For the same reason, it is not possible to guess the order of named parameters a template was transcluded with.

Brief

(IN FUNCTIONS ONLY, DOES NOT AFFECT MODIFIERS) When the time will come, all parameters will be dispatched sorted: first non numerical ones in natural order, then the numerical ones in ascending order

Syntax

{{#invoke:params|reassorted|pipe function name}}

This modifier is identical to all_sorted, but numbers are iterated last (as in “bar, foo, hello, zebra, 1, 2, 3, …”).

 Note: The reassorted modifier cannot be used with functions that propagate several parameters together in a single call, like concat_and_call, concat_and_invoke, and concat_and_magic, because during a call the order of arguments is always lost. For the same reason, it is not possible to guess the order of named parameters a template was transcluded with.

Brief

Define glue strings

Syntax

{{#invoke:params|setting|directives|...|pipe function name}}

This modifier allows some internal variables to be set and later be used by functions. It takes a variable number of arguments, relying on the first argument to understand how many other arguments to read. A few examples will introduce it better than words:

• {{#invoke:params|setting|i|{{!}}|list_values}}

  ↳ Set the value of iteration delimiter to |, then list all values

• {{#invoke:params|setting|ih|{{!}}|list_values}}

  ↳ Set the value of both header text and iteration delimiter to |, then list all values

• {{#invoke:params|setting|ih/p|{{!}}|{{=}}|list}}

  ↳ Set the value of both header text and iteration delimiter to |, set key-value pair delimiter to =, then list all parameters

• {{#invoke:params|setting|ih/p/n|{{!}}|{{=}}|No parameters were passed|list}}

  ↳ Set the value of both header text and iteration delimiter to |, set key-value pair delimiter to =, set fallback text to No parameters were passed, then list all parameters

The first argument is a slash-separated list of lists of slots to assign; one slot is referred by exactly one character and each list of slots maps exactly one argument. A slot indicates which internal variable to set. If more than one slot is aggregated within the same slash-separated list the same text will be assigned to more than one variable.

The slots available are the following:

All space characters in the directives arguments are discarded. Therefore writing {{#invoke:params|setting|ih/p|...}} will be equivalent to writing

{{#invoke:params|setting| i
	h	/ p |...}}

In theory, instead of assigning different slots at once (i.e. {{...|setting|ih/p|{{!}}|{{=}}|...}}), it is possible to write separate invocations of setting for each variable, as in {{...|setting|ih|{{!}}|setting|p|{{=}}...}}. This method however will be slightly less efficient.

Sometimes it might be necessary to make the values assigned depend on conditional expressions. For instance, the following imaginary {{Foobar see also}} template uses the #ifexpr parser function to properly show the “and” conjunction and possibly an Oxford comma when more than two page names are provided:

{{Hatnote|{{{altphrase|Foobar see also}}}: {{#if:{{{1|}}}
	|{{#invoke:params|sequential|squeezing|setting|i/l|, |{{#ifexpr:{{#invoke:params|sequential|squeezing|count}} > 2|,}} and |trimming_values|for_each|[[$@]]}}
	|{{Error|{{tl|Foobar see also}} requires at least one page name}}
}}}}

You can find this example at {{./doc/examples/Oxford comma}}. For instance, {{module:params/doc/examples/Oxford comma|Latin|English|German|Italian}} will generate

 Note: The setting modifier will be trimmed of its surrounding spaces. The directives argument will be stripped of all space characters, including internal spaces. All the other arguments passed to this modifier will be parsed verbatim (i.e. leading and trailing spaces will not be removed).

Brief

Rearrange all parameters that have numerical names to form a compact sequence starting from 1, keeping the same order

Syntax

{{#invoke:params|squeezing|pipe function name}}

Example:

{{#invoke:params|squeezing|sequential|setting|i/p|<br />|: |list}}

This modifier does not take arguments besides the name of the function that will follow.

The following three concatenations will lead to the same result of discarding all parameters with numerical names:

1. {{...|non-sequential|squeezing|...}}
2. {{...|squeezing|non-sequential|...}}
3. {{...|with_name_not_matching|^%-?%d+$|...}}

Brief

Assign an empty string to all undefined numerical parameters between 1 or the lowest numerical parameter name provided and the maximum numerical parameter provided

Syntax

{{#invoke:params|filling_the_gaps|pipe function name}}

Example:

{{#invoke:params|filling_the_gaps|sequential|setting|i/p|<br />|: |list}}

This modifier does not take arguments besides the name of the function that will follow.

Note that when all numerical parameters are lower than 1, the gap between 1 and the maximum numerical parameter will not be filled. The following table provides some examples.

 Note: There is a safety limit of at most 1024 undefined parameters that can be filled using this modifier.

Brief

Remove all numerical parameters that are not in the sequence

Syntax

{{#invoke:params|clearing|pipe function name}}

This modifier does not take arguments besides the name of the function that will follow.

Unlike sequential – which affects only the way parameters are shown – this modifier actually removes all non-sequential numerical parameters, albeit leaves non-numerical parameters intact.

Example:

{{#invoke:params|clearing|setting|i/p|<br />|: |list}}

If you want to remove also non-numerical parameters, add the with_name_matching modifier:

{{#invoke:params|clearing|with_name_matching|^%d+$|setting|i/p|<br />|: |list}}

If you want instead to remove sequential parameters and leave the rest, use {{...|cutting|-1|1|...}}:

{{#invoke:params|cutting|-1|1|setting|i/p|<br />|: |list}}

Brief

Remove zero or more parameters from the beginning and the end of the parameters' sequence

Syntax

{{#invoke:params|cutting|left trim|right trim|pipe function name}}

The first argument indicates how many sequential parameters must be removed from the beginning of the parameter sequence, the second argument indicates how many sequential parameters must be removed from the end of the parameter list. If any of the two arguments contains a negative number its absolute value indicates what must be left on the opposite side – i.e. {{#invoke:params|cutting|-3|0|list}} indicates that the last three arguments must not be discarded.

Example:

{{#invoke:params|cutting|0|2|sequential|call_for_each_value|example template}}

If the absolute value of the sum of the two arguments (left and right cut) is greater than the number of sequential parameters available, the behavior will be the same as if the sum had been equal to the number of sequential parameters available, both when this is a positive value and when it is a negative value (with opposite results). After the desired sequential parameters have been discarded, all numerical parameters will be shifted accordingly.

In some cases it might be necessary to concatenate more than one invocation of the cutting modifier. For instance, the following code prints the last unnamed parameter passed, but only if at least two parameters were passed:

{{#invoke:params|sequential|cutting|1|0|cutting|-1|0|list_values}}

 Suggestion: Although {{#invoke:params|cutting|-1|1|...}} de facto gets rid of all sequential parameters, in most cases it is clearer and more idiomatic to write {{#invoke:params|non-sequential|...}} to obtain the same effect. The last method however cannot be used when it is important that sequential parameters are removed before a particular modifier is called, because non-sequential does not take effect until the final function is invoked. Writing instead {{#invoke:params|sequential|cutting|-1|1|...}} will leave zero arguments to show.

Brief

Remove zero or more parameters from the beginning and the end of the list of numerical parameters (not only the sequential ones)

Syntax

{{#invoke:params|cropping|left crop|right crop|pipe function name}}

This modifier is very similar to cutting, but instead of removing arguments from the extremities of the parameters' sequence, arguments will be removed counting from the first and the last numerical arguments given (i.e. |-1000=... and |1000=... in the case of {{foobar|-1000=hello|1=my|1000=darling}}). If any of the two arguments contains a negative number its absolute value indicates what must be left on the opposite side.

Example:

{{#invoke:params|cropping|2|1|sequential|call_for_each_value|example template}}

For instance, when a template transcluded as {{example template|-2=minus two|0=zero|1=one|2=two|3=three|19=nineteen|20=twenty}} uses the cutting modifier with 2 and 1 as arguments, as in the example above, the following parameters will be left:

-2: minus two

0: zero

16: nineteen

17: twenty]

If instead the template uses the cropping modifier with 2 and 1 as arguments, the following parameters will be left:

0: zero

1: one

2: two

3: three

19: nineteen

If the absolute value of the sum of the two arguments (left and right crop) is greater than the difference between the largest and the lowest numerical parameters available, the behavior will be the same as if the sum had been equal to the number of numerical parameters available, both when this is a positive value and when it is a negative value (with opposite results). When sequential parameters are present among the discarded parameters, all the remaining numerical parameters greater than zero will be shifted accordingly.

Brief

Remove zero or more parameters from any point of the list of numerical parameters, shifting everything accordingly

Syntax

{{#invoke:params|purging|start offset|length|pipe function name}}

The first argument indicates at which point in the parameter list the removal must begin, the second argument indicates how many parameters must be discarded among it and what lies on the right side. If the second argument contains zero or a negative number its absolute value indicates what must be left at the end of the right side of the list of numerical parameters – i.e. {{#invoke:params|purging|5|0|list}} indicates that every numerical argument whose numerical name is greater than 4 must be removed.

Example:

{{#invoke:params|purging|2|1|call_for_each_value|example template}}

Brief

Remove zero or more parameters from any point of the list of numerical parameters, moving backwards and shifting everything accordingly

Syntax

{{#invoke:params|backpurging|start offset|length|pipe function name}}

The first argument indicates at which point in the parameter list the removal must begin, the second argument indicates how many parameters must be discarded among it and what lies on the left side. If the second argument contains zero or a negative number its absolute value indicates what must be left at the end of the left side of the list of numerical parameters – i.e. {{#invoke:params|purging|5|0|list}} indicates that every numerical argument whose numerical name is less than 6 must be removed.

Example:

{{#invoke:params|backpurging|3|1|call_for_each_value|example template}}

The following code removes all parameters with negative and zero numerical names, then lists the rest:

{{#invoke:params|backpurging|0|0|for_each|[$#: $@]}}

Brief

Reverse the order of all numerical parameters (not only sequential ones), making sure that the largest numerical parameter and |1= are swapped

Syntax

{{#invoke:params|rotating|pipe function name}}

This modifier does not take arguments besides the name of the function that will follow.

Example:

{{#invoke:params|rotating|for_each|[$#: $@]}}

Brief

Sort the order of sequential values

Syntax

{{#invoke:params|sorting_sequential_values|[criterion]|pipe function name}}

 Note: This modifier sorts sequential parameters based on their values. If you want to sort the way functions iterate across all parameters based on their names, see all_sorted.

This modifier optionally supports one argument to specify the sorting criterion. If this is omitted it is assumed that sequential values must be ordered alphabetically. Currently the only other possible criterion is naturally, for ordering sequential values in natural sort order.

Example (alphabetical sort order):

{{#invoke:params|sorting_sequential_values|for_each|[$#: $@]}}

Example (natural sort order):

{{#invoke:params|sorting_sequential_values|naturally|for_each|[$#: $@]}}

Brief

Impose a new value to a parameter

Syntax

{{#invoke:params|imposing|name|value|pipe function name}}

Example:

{{#invoke:params|imposing|foo|bar|imposing|hello|world|for_each|[$#: $@]}}

 Note: The value assigned will not be trimmed of its leading and trailing spaces. The name of the parameter and the imposing modifier name itself, however, will be trimmed of their surrounding spaces.

Brief

Assign a new value to a parameter, but only when missing

Syntax

{{#invoke:params|providing|name|value|pipe function name}}

Example:

{{#invoke:params|providing|foo|bar|providing|hello|world|for_each|[$#: $@]}}

 Note: The value assigned will not be trimmed of its leading and trailing spaces. The name of the parameter and the providing modifier name itself, however, will be trimmed of their surrounding spaces.

Brief

Discard one or more numerical parameters or one non-numerical parameter

Syntax

{{#invoke:params|discarding|name|[how many]|pipe function name}}

If, and only if, the name of the parameter is numerical, it is possible to add a second argument to indicate how many contiguous parameters must be discarded starting from the first argument. If the discarded parameters is part of the parameters' sequence one or more holes will be created. To avoid creating holes, use purging or backpurging.

Example #1 (discard the parameter named |hello=):

{{#invoke:params|discarding|hello|for_each|[$#: $@]}}

Example #2 (discard the parameter named |5=):

{{#invoke:params|discarding|5|for_each|[$#: $@]}}

Example #3 (discard the parameters named |1=, |2=, |3= and |4=):

{{#invoke:params|discarding|1|4|for_each|[$#: $@]}}

It is possible to use this modifier to check for unknown parameters:

{{#ifexpr:{{#invoke:params|discarding|hello|discarding|wind|count}} > 0
	|{{Error|Error: The only parameters accepted are {{para|hello}} and {{para|wind}}.}}
	|Everything is good: do something
}}

You can find this example at {{./doc/examples/check for unknown parameters}}. For instance, {{module:params/doc/examples/check for unknown parameters|hello=world|wind=surfing}} will generate

Everything is good: do something

For simple cases like this, however, specialized modules are available; you might want to have a look at:

• {{#invoke:Check for unknown parameters|check}}
• {{#invoke:Check for deprecated parameters|check}}
• {{#invoke:Check for clobbered parameters|check}}
• {{#invoke:Parameter validation|validateparams}}
• {{#invoke:TemplatePar|valid}}

When used to discard single parameters, this modifier is equivalent to writing ...|with_name_not_matching|parameter name|strict|.... However, due to the fact that with_name_not_matching needs to cross-check for the possible presence of or keywords, using discarding will be slightly more efficient.

 Note: All arguments passed to this modifier and the discarding modifier name itself will be trimmed of their surrounding spaces.

Brief

Discard all parameters whose name does not match any of the given patterns

Syntax

{{#invoke:params|with_name_matching|target 1|[plain flag 1]|[or]|[target 2]|[plain flag 2]|[or]|[...]|[target N]|[plain flag N]|pipe function name}}

Internally this modifier uses Lua's string.find() function to find whether parameter names match against given patterns; therefore, unless a plain flag is set, please use the same syntax of Lua patterns. The plain flag can be either plain or strict or omitted. When omitted it is assumed that the target string is a Lua pattern. The difference between plain and strict is that the latter also requires that the lengths match (this happens only when the two strings are 100% identical). In order to facilitate wikitext scripting in the plain flag argument, the pattern keyword is available too, equivalent to omitting the argument.

To express a logical OR the or keyword is available. To express a logical AND instead, concatenate more invocations of with_name_matching.

For the sake of argument we will imagine that we are invoking with_name_matching from within the {{Infobox artery}} template, and this is being called with the following parameters:

Test cases:

• List only the parameters whose names match against the ^Image pattern:

  ↳ {{#invoke:params|setting|ih/p|{{!}}|{{=}}|with_name_matching|^Image|list}}

  ↳ |Image={{Heart diagram 250px}}|Image2=Alveoli diagram.png

• List the parameters whose names match against both patterns ^Image and %d+$:

  ↳ {{#invoke:params|setting|ih/p|{{!}}|{{=}}|with_name_matching|^Image|with_name_matching|%d+$|list}}

  ↳ |Image2=Alveoli diagram.png

• List the parameters whose names match against either the ^Name or the ^Latin$ pattern:

  ↳ {{#invoke:params|setting|ih/p|{{!}}|{{=}}|with_name_matching|^Name$|or|^Latin$|list}}

  ↳ |Latin=truncus pulmonalis, arteria pulmonalis|Name=Pulmonary artery

• List the parameters whose names match against either the ma plain string or the me$ pattern:

  ↳ {{#invoke:params|setting|ih/p|{{!}}|{{=}}|with_name_matching|ma|plain|or|me$|list}}

  ↳ |Image={{Heart diagram 250px}}|Name=Pulmonary artery|Image2=Alveoli diagram.png

Using with_name_matching it is easy to emulate the behaviour of Module:Enumerate (or similar modules). For instance, the following examples creates a bullet list of all the parameters passed of type |foobar1, |foobar2 … |foobarN:

{{#invoke:params|all_sorted|with_name_matching|^foobar%d+$|setting|ih|
* |list_values}}

It is possible to see this example live at {{./doc/examples/enumerate}}.

 Note: The target arguments passed to this modifier will not be trimmed of their leading and trailing spaces. The or, plain, strict and pattern keywords, and the with_name_matching modifier name itself, however, will be trimmed of their surrounding spaces.

Brief

Discard all parameters whose name matches all the given patterns

Syntax

{{#invoke:params|with_name_not_matching|target 1|[plain flag 1]|[and]|[target 2]|[plain flag 2]|[and]|[...]|[target N]|[plain flag N]|pipe function name}}

Internally this modifier uses Lua's string.find() function to find whether parameter names match against given patterns; therefore, unless a plain flag is set, please use the same syntax of Lua patterns. The plain flag can be either plain or strict or omitted. When omitted it is assumed that the target string is a Lua pattern. The difference between plain and strict is that the latter also requires that the lengths match (this happens only when the two strings are 100% identical). In order to facilitate wikitext scripting in the plain flag argument, the pattern keyword is available too, equivalent to omitting the argument.

To express a logical OR the or keyword is available. To express a logical AND instead, concatenate more invocations of with_name_not_matching.

For the sake of argument we will imagine that we are invoking with_name_not_matching from within the {{Infobox artery}} template, and this is being transcluded using the same parameters that we had imagined in the previous example at with_name_matching:

• List only the parameters whose names do not match against the a pattern:

  {{#invoke:params|setting|ih/p|{{!}}|{{=}}|with_name_not_matching|a|list}}

  ↳ |Precursor=truncus arteriosus|Supplies=|Vein=pulmonary vein

• List the parameters whose names do not match against the a plain string and do not match against the l plain string either:

  {{#invoke:params|setting|ih/p|{{!}}|{{=}}|with_name_not_matching|a|plain|with_name_not_matching|l|plain|list}}

  ↳ |Precursor=truncus arteriosus|Vein=pulmonary vein

• List the parameters whose names do not match against either the a plain string or the n plain string:

  {{#invoke:params|setting|ih/p|{{!}}|{{=}}|with_name_not_matching|a|plain|or|n|plain|list}}

  ↳ |Precursor=truncus arteriosus|Supplies=|Image={{Heart diagram 250px}}|Name=Pulmonary artery|Image2=Alveoli diagram.png|Vein=pulmonary vein

* For the sake of efficiency, please don't use this modifier with the strict flag, use discarding instead!

 Note: The target arguments passed to this modifier will not be trimmed of their leading and trailing spaces. The or, plain, strict and pattern keywords, and the with_name_not_matching modifier name itself, however, will be trimmed of their surrounding spaces.

Brief

Discard all parameters whose value does not match any of the given patterns

Syntax

{{#invoke:params|with_value_matching|target 1|[plain flag 1]|[or]|[target 2]|[plain flag 2]|[or]|[...]|[target N]|[plain flag N]|pipe function name}}

Exactly like with_name_matching, but applied to parameter values instead of names.

Internally this modifier uses Lua's string.find() function to find whether parameter names match against given patterns; therefore, unless a plain flag is set, please use the same syntax of Lua patterns. The plain flag can be either plain or strict or omitted. When omitted it is assumed that the target string is a Lua pattern. The difference between plain and strict is that the latter also requires that the lengths match (this happens only when the two strings are 100% identical). In order to facilitate wikitext scripting in the plain flag argument, the pattern keyword is available too, equivalent to omitting the argument.

Example:

{{#invoke:params|with_value_matching|banana|count}}

 Note: The target arguments passed to this modifier will not be trimmed of their leading and trailing spaces. The or, plain, strict and pattern keywords, and the with_value_matching modifier name itself, however, will be trimmed of their surrounding spaces.

Brief

Discard all parameters whose value matches all the given patterns

Syntax

{{#invoke:params|with_value_not_matching|target 1|[plain flag 1]|[and]|[target 2]|[plain flag 2]|[and]|[...]|[target N]|[plain flag N]|pipe function name}}

Exactly like with_name_not_matching, but applied to parameter values instead of names.

Internally this modifier uses Lua's string.find() function to find whether parameter names match against given patterns; therefore, unless a plain flag is set, please use the same syntax of Lua patterns. The plain flag can be either plain or strict or omitted. When omitted it is assumed that the target string is a Lua pattern. The difference between plain and strict is that the latter also requires that the lengths match (this happens only when the two strings are 100% identical). In order to facilitate wikitext scripting in the plain flag argument, the pattern keyword is available too, equivalent to omitting the argument.

For instance, before calling list, the following code will get rid of all blank parameters (i.e. parameters whose values contain only zero or more spaces):

{{#invoke:params|with_value_not_matching|^%s*$|setting|hi/p|{{!}}|{{=}}|list}}

A typical use case of this modifier is that of purging all empty incoming parameters before calling another template, especially when this distinguishes between empty and undefined parameters.

{{#invoke:params|with_value_not_matching|^%s*$|concat_and_call|my template}}

 Note: The target arguments passed to this modifier will not be trimmed of their leading and trailing spaces. The or, plain, strict and pattern keywords, and the with_value_not_matching modifier name itself, however, will be trimmed of their surrounding spaces.

Brief

Remove leading and trailing spaces from values

Syntax

{{#invoke:params|trimming_values|pipe function name}}

This modifier does not take arguments besides the name of the function that will follow.

Most modifiers are order-dependent, therefore placing trimming_values in different positions can generate different results. For instance, imagining our {{example template}} being called with the following spaced arguments: {{example template| wanna | be | my | friend | ? }}. If {{example template}} contained the following code,

{{#invoke:params|with_value_matching|%s+$|trimming_values|setting|i/p|{{!}}|{{=}}|list}}

the following text would be printed: 1=wanna|2=be|3=my|4=friend|5=?. But if instead it contained the following code,

{{#invoke:params|trimming_values|with_value_matching|%s+$|setting|i/p|{{!}}|{{=}}|list}}

no arguments would be shown.

Order affects also performance, and how many values will be trimmed of their leading and trailing spaces will depend on where trimming_values is placed. For instance, if a template were invoked with 50 parameters and its code contained {{#invoke:params|trimming_values|cutting|-1|0|list}}, first all its values would be trimmed of leading and trailing blank spaces and then its first 49 parameters would be discarded. On the other hand, writing {{#invoke:params|cutting|-1|0|trimming_values|list}} would first discard 49 parameters and then trim the only value left, resulting in a more efficient code. As a general rule, placing trimming_values as the last modifier is usually the best choice.

In most cases placing trimming_values together with non-sequential will result in an empty call with no effects, because non-sequential parameters are normally stripped of their leading and trailing spaces by default – this however depends on the caller, and if the current template is being called by a module it is in theory possible in specific conditions for named parameters to retain their leading and trailing spaces (namely in non-sequential numerical parameters).

Using trimming_values makes this module behave like many Wikipedia modules behave. For example, if we wanted to emulate {{#invoke:Separated entries|main}}, writing

{{#invoke:params|sequential|squeezing|trimming_values|setting|i|XXXX|list_values}}

will be equivalent to writing,

{{#invoke:separated entries|main|separator=XXXX}}

whereas writing

{{#invoke:params|sequential|squeezing|trimming_values|setting|i/l|XXXX|YYYY|list_values}}

will be equivalent to writing

{{#invoke:separated entries|main|separator=XXXX|conjunction=YYYY}}

The {{./doc/examples/trim and call}} example template shows how to call any arbitrary template trimming all parameters beforehand.

Brief

Map all parameter values, replacing their content with the expansion of a given template repeatedly called with one parameter (the parameter's value)

Syntax

{{#invoke:params|mapping_by_calling|template name|[call style]|[let]|[...]|[number of additional parameters]|[parameter 1]|[parameter 2]|[...]|[parameter N]|pipe function name}}

This modifier (temporarily) changes the content of the parameters the current template is being called with, replacing each of them with the text returned by another template. The latter will be repeatedly called with at least one parameter as first sequential parameter: the parameter's value.

It is possible to pass the parameter's value as a different parameter, or pass the parameter's name as well, by specifying a call style flag immediately after the template name (see below).

If the call style flag or (if omitted) the template name is followed by one or more groups of three arguments led by the let keyword (i.e. let|name|value), these will be passed to the mapping template.

If the last group of three arguments or (if omitted) the call style flag or (if omitted) the template name is followed by a number, this will be parsed as the amount of positional parameters to add. These will always follow the parameter's name and value if any of the latter has a numerical name greater than zero.

In case of collisions, the parameters assigned via the let keyword will be given precedence over everything else.

For instance, before listing all parameters,

{{#invoke:params|mapping_by_calling|foobar|setting|i/p|{{!}}|{{=}}|list}}

will replace each value with the expansion of {{foobar|VALUE}} (where VALUE indicates each different value).

On the other hand,

{{#invoke:params|mapping_by_calling|foobar|names_and_values|let|rice|nope|let|curry|lots!|2|hello|world|setting|i/p|{{!}}|{{=}}|list}}

will do the same, but using the expansion of {{foobar|NAME|VALUE|hello|world|rice=nope|curry=lots!}} (where NAME and VALUE indicate each different name and value).

Possible call style flags are:

If the call style flags argument is omitted it defaults to values_only.

 Note: All arguments passed to this modifier except the mapping_by_calling modifier name itself, the template name, the call style flag, the let keyword, the passed parameter names, and the number of additional parameters will not be trimmed of their leading and trailing spaces.

Brief

Map all parameter values, replacing their content with the text returned by a given module function repeatedly invoked with at least one argument (the parameter's value)

Syntax

{{#invoke:params|mapping_by_invoking|module name|function name|[call style]|[let]|[...]|[number of additional arguments]|[argument 1]|[argument 2]|[...]|[argument N]|pipe function name}}

This modifier (temporarily) changes the content of the parameters the current template is being called with, replacing each of them with the text returned by a custom module function. The latter will be repeatedly called with at least one argument as first sequential argument: the parameter's value.

It is possible to pass the parameter's value as a different argument, or pass the parameter's name as well, by specifying a call style flag immediately after the function name (see mapping_by_calling for the list of possible flags). If omitted, the call style flags argument defaults to values_only.

If the call style flag or (if omitted) the function name is followed by one or more groups of three arguments led by the let keyword (i.e. let|name|value), these will be passed to the mapping module function.

If the last group of three arguments or (if omitted) the call style flag or (if omitted) the function name is followed by a number, this will be parsed as the amount of positional parameters to add. These will always follow the parameter's name and value if any of the latter has a numerical name greater than zero.

In case of collisions, the arguments assigned via the let keyword will be given precedence over everything else.

For instance, before listing all parameters,

{{#invoke:params|mapping_by_invoking|foobar|main|setting|i/p|{{!}}|{{=}}|list}}

will replace each value with the expansion of {{#invoke:foobar|main|VALUE}} (where VALUE indicates each different value).

On the other hand,

{{#invoke:params|mapping_by_invoking|foobar|main|names_and_values|let|rice|nope|let|curry|lots!|2|hello|world|setting|i/p|{{!}}|{{=}}|list}}

will do the same, but using the expansion of {{#invoke:foobar|main|NAME|VALUE|hello|world|rice=nope|curry=lots!}} (where NAME and VALUE indicate each different name and value).

 Note: All arguments passed to this modifier except the mapping_by_invoking modifier name itself, the module name, the function name, the call style flag, the let keyword, the passed parameter names, and the number of additional arguments will not be trimmed of their leading and trailing spaces.

Brief

Map all parameter values, replacing their content with the expansion of a given parser function repeatedly called with at least one argument (the parameter's value)

Syntax

{{#invoke:params|mapping_by_magic|parser function|[call style]|[let]|[...]|[number of additional arguments]|[argument 1]|[argument 2]|[...]|[argument N]|pipe function name}}

This modifier (temporarily) changes the content of the parameters the current template is being called with, replacing each of them with the text returned by a parser function. The latter will be repeatedly called with at least one argument as first sequential argument: the parameter's value.

It is possible to pass the parameter's value as a different argument, or pass the parameter's name as well, by specifying a call style flag immediately after the parser function name (see mapping_by_calling for the list of possible flags). If omitted, the call style flags argument defaults to values_only.

If the call style flag or (if omitted) the template name is followed by one or more groups of three arguments led by the let keyword (i.e. let|name|value), these will be passed to the parser function.

If the last group of three arguments or (if omitted) the call style flag or (if omitted) the template name is followed by a number, this will be parsed as the amount of positional arguments to add. These will always follow the parameter's name and value if any of the latter has a numerical name greater than zero.

In case of collisions, the arguments assigned via the let keyword will be given precedence over everything else.

For instance, before listing all parameters,

{{#invoke:params|mapping_by_magic|uc|setting|i/p|{{!}}|{{=}}|list}}

will replace each value with the expansion of {{uc:VALUE}} (where VALUE indicates each different value).

On the other hand,

{{#invoke:params|mapping_by_magic|plural|names_and_values|1|They are many|setting|i/p|{{!}}|{{=}}|list}}

will do the same, but using the expansion of {{plural:NAME|VALUE|They are many}} (where NAME and VALUE indicate each different name and value).

 Note: All arguments passed to this modifier except the mapping_by_magic modifier name itself, the parser function's name, the call style flag, the let keyword, the passed parameter names, and the number of additional arguments will not be trimmed of their leading and trailing spaces.

Brief

Map all parameter values performing string substitutions

Syntax

{{#invoke:params|mapping_by_replacing|target|replace|[count]|[plain flag]|pipe function name}}

This modifier (temporarily) changes the content of the parameters the current template is being called with, replacing each of them with the result of a string substitution. Its syntax is very simlar to {{#invoke:string|replace}}.

Internally the modifier uses Lua's string.gsub() function to perform substitutions; therefore, unless a plain flag is set, please use the same syntax of Lua patterns. The plain flag can be either plain or strict or omitted. When omitted it is assumed that the target string is a Lua pattern. The difference between plain and strict is that the latter also requires that the lengths match (this happens only when the two strings are 100% identical). In strict mode the replace argument will not accept directives (e.g. %0, %1, etc.). In order to facilitate wikitext scripting in the plain flag argument, the pattern keyword is available too, equivalent to omitting the argument.

The count argument prescribes how many substitutions will be performed at most. If blank or omitted, all matches found will be substituted.

Almost everything this modifier can do can also be done via ...|mapping_by_invoking|string|replace|4|.... And so, writing

...|mapping_by_renaming|foo|bar|1|plain|...

will be equivalent to writing

...|mapping_by_invoking|string|replace|4|foo|bar|1|true|...

The first syntax however will less computationally expensive.

At {{./doc/examples/informal tablebox}} you can find an example on how to exploit this function to create “informal” infoboxes.

 Note: The target and replace arguments passed to this modifier will not be trimmed of their leading and trailing spaces. The or, plain, strict and pattern keywords, the count argument, and the mapping_by_replacing modifier name itself, however, will be trimmed of their surrounding spaces.

Brief

Rename all parameters, replacing their former names with the expansion of a given template repeatedly called with at least one parameter (the parameter's former name)

Syntax

{{#invoke:params|renaming_by_calling|template name|[call style]|[let]|[...]|[number of additional parameters]|[parameter 1]|[parameter 2]|[...]|[parameter N]|pipe function name}}

This modifier works similarly to mapping_by_calling, but instead of replacing parameters' values it renames the parameters themselves. Care must be used knowing that if a new name collides with another new name one of the two parameters will be removed without knowing which one. New names and old names do not create collisions. If a name is returned identical it will be considered as “unchanged” and in case of conflicts the renamed one will prevail. Possible leading and trailing spaces in the new names are always stripped. Here, if omitted, the call style flags argument defaults to names_only.

For instance, the following example uses {{2x}} to rename all incoming parameters by doubling their names:

{{#invoke:params|setting|h/i/p/f|[|][|: |]|renaming_by_calling|2x|list}}

Same, but adding a hyphen in between:

{{#invoke:params|setting|h/i/p/f|[|][|: |]|renaming_by_calling|2x|1|-|list}}

This modifier can be particularly useful for sanitizing parameter names (e.g. collapsing several spaces into single spaces, changing the letter case, and so on).

 Note: All arguments passed to this modifier except the renaming_by_calling modifier name itself, the template name, the call style flag, the let keyword, the passed parameter names, and the number of additional arguments will not be trimmed of their leading and trailing spaces.

Brief

Rename all parameters, replacing their former names with the text returned by a given module function repeatedly called with at least one argument (the parameter's former name)

Syntax

{{#invoke:params|renaming_by_invoking|module name|function name|[call style]|[let]|[...]|[number of additional arguments]|[argument 1]|[argument 2]|[...]|[argument N]|pipe function name}}

This modifier works similarly to mapping_by_invoking, but instead of replacing parameters' values it renames the parameters themselves. Care must be used knowing that if a new name collides with another new name one of the two parameters will be removed without knowing which one. New names and old names do not create collisions. If a name is returned identical it will be considered as “unchanged” and in case of conflicts the renamed one will prevail. Possible leading and trailing spaces in the new names are always stripped. Here, if omitted, the call style flags argument defaults to names_only.

For instance, the following example uses {{#invoke:string|replace}} to rename all parameters of type |arg1=, |arg2=, … |argN= into |1=, |2= … |N=, thus creating a novel sequence:

{{#invoke:params|sequential|setting|h/i/p/f|[|][|: |]|with_name_matching|^arg%d+$|renaming_by_invoking|string|replace|4|^arg(%d+)$|%1|1|false|list}}

This modifier can be particularly useful for sanitizing parameter names (e.g. collapsing several spaces into single spaces, changing the letter case, and so on).

 Note: All arguments passed to this modifier except the renaming_by_invoking modifier name itself, the module name, the function name, the call style flag, the let keyword, the passed parameter names, and the number of additional arguments will not be trimmed of their leading and trailing spaces.

Brief

Rename all parameters, replacing their former names with the text returned by a given parser function repeatedly called with at least one argument (the parameter's former name)

Syntax

{{#invoke:params|renaming_by_magic|parser function|[call style]|[let]|[...]|[number of additional arguments]|[argument 1]|[argument 2]|[...]|[argument N]|pipe function name}}

This modifier works similarly to mapping_by_magic, but instead of replacing parameters' values it renames the parameters themselves. Care must be used knowing that if a new name collides with another new name one of the two parameters will be removed without knowing which one. New names and old names do not create collisions. If a name is returned identical it will be considered as “unchanged” and in case of conflicts the renamed one will prevail. Possible leading and trailing spaces in the new names are always stripped. Here, if omitted, the call style flags argument defaults to names_only.

This modifier can be particularly useful for sanitizing parameter names (e.g. changing the letter case, or URL encoding/decoding, and so on).

For instance, the following example uses {{lc}} to sanitize all parameter names confining them to their lower case version:

{{#invoke:params|sequential|setting|h/i/p/f|[|][|: |]|renaming_by_magic|lc|list}}

 Note: All arguments passed to this modifier except the renaming_by_magic modifier name itself, the parser function name, the call style flag, the let keyword, the passed parameter names, and the number of additional arguments will not be trimmed of their leading and trailing spaces.

Brief

Rename all parameters, replacing their former names with the text returned by a string substitutions

Syntax

{{#invoke:params|renaming_by_replacing|target|replace|[count]|[plain flag]|pipe function name}}

This modifier works similarly to mapping_by_replacing, but instead of replacing parameters' values it renames the parameters themselves. Care must be used knowing that if a new name collides with another new name one of the two parameters will be removed without knowing which one. New names and old names do not create collisions. If a name is returned identical it will be considered as “unchanged” and in case of conflicts the renamed one will prevail. Possible leading and trailing spaces in the new names are always stripped.

For instance, the following example renames all parameters of type |arg1=, |arg2=, … |argN= into |1=, |2= … |N=, thus creating a novel sequence:

{{#invoke:params|sequential|setting|h/i/p/f|[|][|: |]|with_name_matching|^arg%d+$|renaming_by_replacing|^arg(%d+)$|%1|1|list}}

This modifier can be particularly useful for sanitizing parameter names (e.g. collapsing several spaces into single spaces, changing the letter case, and so on).

 Note: The target and replace arguments passed to this modifier will not be trimmed of their leading and trailing spaces. The or, plain, strict and pattern keywords, the count argument, and the mapping_by_replacing modifier name itself, however, will be trimmed of their surrounding spaces.

Brief

Group the parameters that have the same numerical suffix into novel parameters, whose names will be numbers and whose values will be decided by a custom template

Syntax

{{#invoke:params|grouping_by_calling|template name|[let]|[...]|[number of additional arguments]|[argument 1]|[argument 2]|[...]|[argument N]|pipe function name}}

This is the piping version of call_for_each_group. This means that after calling this modifier the old parameters will be (temporarily) gone and the only parameters left will be novel parameters whose names will be numbers (or an empty string if parameters without a numerical suffix were present) and whose content will be decided by a custom template.

Like other modifiers in the mapping_* and renaming_* family, it is possible to impose own parameters on the callback template by using the syntax ...|[let]|[...]|[number of additional arguments]|[argument 1]|[argument 2]|[...]|[argument N]|.... Unlike the other mapping_* and renaming_* modifiers, however (but like call_for_each_group), sequential parameters here will not be prepended, but will replace possible parsed parameters.

And so, writing

{{#invoke:params|...|grouping_by_calling|MY TEMPLATE|let|foo|bar|let|hello|world|3|one|two|three|list_values}}

is identical to writing

{{#invoke:params|...|call_for_each_group|MY TEMPLATE|foo=bar|hello=world|one|two|three}}

In the example above the main difference will be that the first solution will allow to pass the newly grouped parameters at once to another template or module (via concat_and_call or concat_and_invoke) or, if needed, perform further fine-tuning operations concerning the new parameters.

Please refer to the documentation of call_for_each_group for further information on the parameters passed to the callback template.

 Note: All arguments passed to this modifier except the grouping_by_calling modifier name itself, the template name, the let keyword, the passed parameter names, and the number of additional parameters will not be trimmed of their leading and trailing spaces.

• Module:Params/ChangeLog – Record of the most important changes in the module's code
• Module:Params/testcases – Testing the module's capabilities
• Module:Params/doc/examples – Some of the examples mentioned in this documentation

The complete list of subpages is available here.

• {{#invoke:TemplatePar}}
• {{#invoke:ParameterCount}}
• {{#invoke:Separated entries|main}}
• {{#invoke:Enumerate|main}}
• {{#invoke:Check for unknown parameters|check}}
• {{#invoke:Check for deprecated parameters|check}}
• {{#invoke:Check for clobbered parameters|check}}
• {{#invoke:Parameter validation}}
• {{#invoke:Expand wikitext|main}}
• {{#invoke:For loop|main}} and {{For loop}}
• {{#invoke:For nowiki|template}} and {{For nowiki}}
• Project:TemplateData