Module:parameters
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- The following documentation is located at Module:parameters/doc.[edit]
- Useful links: subpage list • links • transclusions • testcases • sandbox
local export = {}
local m_str_utils = require("Module:string utilities")
local families_module = "Module:families"
local labels_module = "Module:labels"
local languages_module = "Module:languages"
local parse_utilities_module = "Module:parse utilities"
local references_module = "Module:references"
local scripts_module = "Module:scripts"
local wikimedia_languages_module = "Module:wikimedia languages"
local require_when_needed = require("Module:utilities/require when needed")
local dump = mw.dumpObject
local floor = math.floor
local gsplit = mw.text.gsplit
local gsub = string.gsub
local huge = math.huge
local insert = table.insert
local list_to_set = require("Module:table").listToSet
local list_to_text = mw.text.listToText
local match = string.match
local max = math.max
local pairs = pairs
local pattern_escape = m_str_utils.pattern_escape
local remove_holes = require_when_needed("Module:parameters/remove holes")
local rsplit = m_str_utils.split
local scribunto_param_key = m_str_utils.scribunto_param_key
local sort = table.sort
local trim = mw.text.trim
local type = type
local yesno = require_when_needed("Module:yesno")
--[==[ intro:
This module is used to standardize template argument processing and checking. A typical workflow is as follows (based
on [[Module:translations]]):
{
...
local parent_args = frame:getParent().args
local params = {
[1] = {required = true, type = "language", default = "und"},
[2] = {},
[3] = {list = true},
["alt"] = {},
["id"] = {},
["sc"] = {type = "script"},
["tr"] = {},
["ts"] = {},
["lit"] = {},
}
local args = require("Module:parameters").process(parent_args, params)
-- Do further processing of the parsed arguments in `args`.
...
}
The `params` table should have the parameter names as the keys, and a (possibly empty) table of parameter tags as the
value. An empty table as the value merely states that the parameter exists, but should not receive any special
treatment. Possible parameter tags are listed below:
; {required = true}
: The parameter is required; an error is shown if it is not present. The template's page itself is an exception; no
error is shown there.
; {default =}
: Specifies a default input value for the parameter, if it is absent or empty. This will be processed as though it were
the input instead, so (for example) {default = "und"} with the type {"language"} will return a language object for
[[:Category:Undetermined language|Undetermined language]] if no language code is provided. When used on list
parameters, this specifies a default value for the first item in the list only. Note that it is not possible to
generate a default that depends on the value of other parameters. If used together with {required = true}, the default
applies only to template pages (see the following entry), as a side effect of the fact that "required" parameters
aren't actually required on template pages. This can be used to show an example of the template in action when the
template page is visited; however, it is preferred to use `template_default` for this purpose, for clarity.
; {template_default =}
: Specifies a default input value for absent or empty parameters only on template pages. Template pages are any page in
the template space (beginning with `Template:`) except for documentation pages (those ending in `.../documentation`).
This can be used to provide an example value for a non-required parameter when the template page is visited, without
interfering with other uses of the template. Both `template_default` and `default` can be specified for the same
parameter. If this is done, `template_default` applies on template pages, and `default` on other pages. As an example,
{{tl|cs-IPA}} uses the equivalent of {[1] = {default = "+", template_default = "příklad"}} to supply a default of
{"+"} for mainspace and documentation pages (which tells the module to use the value of the {{para|pagename}}
parameter, falling back to the actual pagename), but {"příklad"} (which means "example"), on [[Template:cs-IPA]].
; {alias_of =}
: Treat the parameter as an alias of another. When arguments are specified for this parameter, they will automatically
be renamed and stored under the alias name. This allows for parameters with multiple alternative names, while still
treating them as if they had only one name. The conversion-related properties of an aliased parameter (e.g. `type`,
`set`, `convert`, `sublist`) are taken from the aliasee, and the corrresponding properties set on the alias itself
are ignored; but other properties on the alias are taken from the alias's spec and not from the aliasee's spec. This
means, for example, that if you create an alias of a list parameter, the alias must also specify the `list` property
or it is not a list. (In such a case, a value specified for the alias goes into the first item of the aliasee's list.
You cannot make a list alias of a non-list parameter; this causes an error to be thrown.) Similarly, if you specify
`separate_no_index` on an aliasee but not on the alias, uses of the unindexed aliasee parameter are stored into the
`.default` key, but uses of the unindexed alias are stored into the first numbered key of the aliasee's list.
Aliases cannot be required, as this prevents the other name or names of the parameter from being used. Parameters
that are aliases and required at the same time cause an error to be thrown.
; {allow_empty = true}
: If the argument is an empty string value, it is not converted to {nil}, but kept as-is.
; {allow_whitespace = true}
: Spacing characters such as spaces and newlines at the beginning and end of a positional parameter are not removed.
(MediaWiki itself automatically trims spaces and newlines at the edge of named parameters.)
; {type =}
: Specifies what value type to convert the argument into. The default is to leave it as a text string. Alternatives are:
:; {type = "boolean"}
:: The value is treated as a boolean value, either true or false. No value, the empty string, and the strings {"0"},
{"no"}, {"n"} and {"false"} are treated as {false}, all other values are considered {true}.
:; {type = "number"}
:: The value is converted into a number, or {nil} if the value is not parsable as a number.
:; {type = "language"}
:: The value is interpreted as a full or [[Wiktionary:Languages#Etymology-only languages|etymology-only language]] code
language code (or name, if {method = "name"}) and converted into the corresponding object (see [[Module:languages]]).
If the code or name is invalid, then an error is thrown. The additional setting {family = true} can be given to allow
[[Wiktionary:Language families|language family codes]] to be considered valid and the corresponding object returned.
Note that to distinguish an etymology-only language object from a full language object, use
{object:hasType("language", "etymology-only")}.
:; {type = "full language"}
:: The value is interpreted as a full language code (or name, if {method = "name"}) and converted into the corresponding
object (see [[Module:languages]]). If the code or name is invalid, then an error is thrown. Etymology-only languages
are not allowed. The additional setting {family = true} can be given to allow
[[Wiktionary:Language families|language family codes]] to be considered valid and the corresponding object returned.
:; {type = "wikimedia language"}
:: The value is interpreted as a code and converted into a wikimedia language object. If the code is invalid, then an
error is thrown. If {method = "fallback"} is specified, conventional language codes which are different from their
Wikimedia equivalent will also be accepted as a fallback.
:; {type = "family"}
:: The value is interpreted as a language family code (or name, if {method = "name"}) and converted into the
corresponding object (see [[Module:families]]). If the code or name is invalid, then an error is thrown.
:; {type = "script"}
:: The value is interpreted as a script code (or name, if {method = "name"}) and converted into the corresponding object
(see [[Module:scripts]]). If the code or name is invalid, then an error is thrown.
:; {type = "qualifier"}
:: The value is interpreted as a qualifier and converted into the correct format for passing into `format_qualifiers()`
in [[Module:qualifiers]] (which currently just means converting it to a one-item list).
:; {type = "labels"}
:: The value is interpreted as a comma-separated list of labels and converted into the correct format for passing into
`show_labels()` in [[Module:labels]] (which is currently a list of strings). Splitting is done on commas not followed
by whitespace, except that commas inside of double angle brackets do not count even if not followed by whitespace.
This type should be used by for normal labels (typically specified using {{para|l}} or {{para|ll}}) and accent
qualifiers (typically specified using {{para|a}} and {{para|aa}}).
:; {type = "references"}
:: The value is interpreted as one or more references, in the format prescribed by `parse_references()` in
[[Module:references]], and converted into a list of objects of the form accepted by `format_references()` in the same
module. If a syntax error is found in the reference format, an error is thrown.
; {list =}
: Treat the parameter as a list of values, each having its own parameter name, rather than a single value. The
parameters will have a number at the end, except optionally for the first (but see also {require_index = true}). For
example, {list = true} on a parameter named "head" will include the parameters {{para|head}} (or {{para|head1}}),
{{para|head2}}, {{para|head3}} and so on. If the parameter name is a number, another number doesn't get appended, but
the counting simply continues, e.g. for parameter {3} the sequence is {{para|3}}, {{para|4}}, {{para|5}} etc. List
parameters are returned as numbered lists, so for a template that is given the parameters `|head=a|head2=b|head3=c`,
the processed value of the parameter {"head"} will be { { "a", "b", "c" }}}.
: The value for {list =} can also be a string. This tells the module that parameters other than the first should have a
different name, which is useful when the first parameter in a list is a number, but the remainder is named. An example
would be for genders: {list = "g"} on a parameter named {1} would have parameters {{para|1}}, {{para|g2}}, {{para|g3}}
etc.
: If the number is not located at the end, it can be specified by putting {"\1"} at the number position. For example,
parameters {{para|f1accel}}, {{para|f2accel}}, ... can be captured by using the parameter name {"f\1accel"}, as is
done in [[Module:headword/templates]].
; {set =}
: Require that the value of the parameter be one of the specified list of values (or omitted, if {required = true} isn't
given). The values in the specified list should be strings corresponding to the raw parameter values except when
{type = "number"}, in which case they should be numbers. The use of `set` is disallowed if {type = "boolean"} and
causes an error to be thrown.
; {sublist =}
: The value of the parameter is a delimiter-separated list of individual raw values. The resulting field in `args` will
be a Lua list (i.e. a table with numeric indices) of the converted values. If {sublist = true} is given, the values
will be split on comma (possibly with whitespace on one or both sides of the comma, which is ignored). Otherwise, the
value of `sublist` should be either a Lua pattern specifying the delimiter(s) to split on or a function to do the
splitting, which is passed two values (the value to split and a function to signal an error) and should return a list
of the split values. A function `split_on_comma_without_whitespace()` is provided in [[Module:parameters]] to split on
commas not followed by whitespace, while considering commas followed by whitespace part of the argument.
; {convert =}
: If given, this specifies a function to convert the raw parameter value into the Lua object used during further
processing. The function is passed two arguments, the raw parameter value itself and a function used to signal an
error during parsing or conversion, and should return one value, the converted parameter. The error-signaling function
contains the name and raw value of the parameter embedded into the message it generates, so these do not need to
specified in the message passed into it. If `type` is specified in conjunction with `convert`, the processing by
`type` happens first. If `sublist` is given in conjunction with `convert`, the raw parameter value will be split
appropriately and `convert` called on each resulting item.
; {family = true}
: When used in conjunction with {type = "language"}, allows [[Wiktionary:Language families|language family codes]] to be
returned. To check if a given object refers to a language family, use {object:hasType("family")}.
; {method = "name"}
: When used in conjunction with {type = "language"}, {type = "family"} or {type = "script"}, checks for and parses a
language, family or script name instead of a code.
; {allow_holes = true}
: This is used in conjunction with list-type parameters. By default, the values are tightly packed in the resulting
list. This means that if, for example, an entry specified `head=a|head3=c` but not {{para|head2}}, the returned list
will be { {"a", "c"}}}, with the values stored at the indices {1} and {2}, not {1} and {3}. If it is desirable to keep
the numbering intact, for example if the numbers of several list parameters correlate with each other (like those of
{{tl|affix}}), then this tag should be specified.
: If {allow_holes = true} is given, there may be {nil} values in between two real values, which makes many of Lua's
table processing functions no longer work, like {#} or {ipairs()}. To remedy this, the resulting table will contain an
additional named value, `maxindex`, which tells you the highest numeric index that is present in the table. In the
example above, the resulting table will now be { { "a", nil, "c", maxindex = 3}}}. That way, you can iterate over the
values from {1} to `maxindex`, while skipping {nil} values in between.
; {disallow_holes = true}
: This is used in conjunction with list-type parameters. As mentioned above, normally if there is a hole in the source
arguments, e.g. `head=a|head3=c` but not {{para|head2}}, it will be removed in the returned list. If
{disallow_holes = true} is specified, however, an error is thrown in such a case. This should be used whenever there
are multiple list-type parameters that need to line up (e.g. both {{para|head}} and {{para|tr}} are available and
{{para|head3}} lines up with {{para|tr3}}), unless {allow_holes = true} is given and you are prepared to handle the
holes in the returned lists.
; {require_index = true}
: This is used in conjunction with list-type parameters. By default, the first parameter can have its index omitted.
For example, a list parameter named `head` can have its first parameter specified as either {{para|head}} or
{{para|head1}}. If {require_index = true} is specified, however, only {{para|head1}} is recognized, and {{para|head}}
will be treated as an unknown parameter. {{tl|affixusex}} (and variants {{tl|suffixusex}}, {{tl|prefixusex}}) use
this, for example, on all list parameters.
; {separate_no_index = true}
: This is used to distinguish between {{para|head}} and {{para|head1}} as different parameters. For example, in
{{tl|affixusex}}, to distinguish between {{para|sc}} (a script code for all elements in the usex's language) and
{{para|sc1}} (the script code of the first element, used when the first element is prefixed with a language code to
indicate that it is in a different language). When this is used, the resulting table will contain an additional named
value, `default`, which contains the value for the indexless argument.
]==]
-------------------------------------- Some splitting functions -----------------------------
--[==[
Split an argument on comma, but not comma followed by whitespace. Can be used e.g. as the value of the `sublist` field
in the `params` structure.
]==]
function export.split_on_comma_without_whitespace(val)
if val:find(",%s") or val:find("\\") then
return require(parse_utilities_module).split_on_comma(val)
else
return rsplit(val, ",")
end
end
-------------------------------------- Value conversion -----------------------------
-- For a list parameter `name` and corresponding value `list_name` of the `list` field (which should have the same value
-- as `name` if `list = true` was given), generate a pattern to match parameters of the list and store the pattern as a
-- key in `patterns`, with corresponding value set to `name`. For example, if `list_name` is "tr", the pattern will
-- match "tr" as well as "tr1", "tr2", ..., "tr10", "tr11", etc. If the `list_name` contains a \1 in it, the numeric
-- portion goes in place of the \1. For example, if `list_name` is "f\1accel", the pattern will match "faccel",
-- "f1accel", "f2accel", etc. Any \1 in `name` is removed before storing into `patterns`.
local function save_pattern(name, list_name, patterns)
name = type(name) == "string" and gsub(name, "\1", "") or name
if match(list_name, "\1") then
patterns["^" .. gsub(pattern_escape(list_name), "\1", "([1-9]%%d*)") .. "$"] = name
else
patterns["^" .. pattern_escape(list_name) .. "([1-9]%d*)$"] = name
end
end
-- Convert a list in `list` to a string, separating the final element from the preceding one(s) by `conjunction`. If
-- `dump_vals` is given, pass all values in `list` through mw.dumpObject() (WARNING: this destructively modifies
-- `list`). This is similar to serialCommaJoin() in [[Module:table]] when used with the `dontTag = true` option, but
-- internally uses mw.text.listToText().
local function concat_list(list, conjunction, dump_vals)
if dump_vals then
for i = 1, #list do
list[i] = dump(list[i])
end
end
return list_to_text(list, nil, conjunction)
end
-- Helper function for use with convert_val_error(). Format a list of possible choices using `concat_list` and
-- conjunction "or", displaying "either " before the choices if there's more than one.
local function format_choice_list(typ)
return (#typ > 1 and "either " or "") .. concat_list(typ, " or ")
end
-- Signal an error for a value `val` that is not of the right typ `typ` (which is either a string specifying a type or
-- a list of possible values, in the case where `set` was used). `name` is the name of the parameter and can be a
-- function to signal an error (which is assumed to automatically display the parameter's name and value). `seetext` is
-- an optional additional explanatory link to display (e.g. [[WT:LOL]], the list of possible languages and codes).
local function convert_val_error(val, name, typ, seetext)
if type(name) == "function" then
if type(typ) == "table" then
typ = "choice, must be " .. format_choice_list(typ)
end
name(("Invalid %s; the value %s is not valid%s"):format(typ, val, seetext and "; see " .. seetext or ""))
else
if type(typ) == "table" then
typ = "must be " .. format_choice_list(typ)
else
typ = "should be a valid " .. typ
end
error(("Parameter %s %s; the value %s is not valid.%s"):format(dump(name), typ, dump(val),
seetext and " See " .. seetext .. "." or ""))
end
end
-- Convert a value that is not a string or number to a string using mw.dumpObject(), for debugging purposes.
local function dump_if_unusual(val)
return (type(val) == "string" or type(val) == "number") and val or dump(val)
end
-- A helper function for use with generating error-signaling functions in the presence of raw value conversion. Format a
-- message `msg`, including the processed value `processed` if it is different from the raw value `rawval`; otherwise,
-- just return `msg`.
local function msg_with_processed(msg, rawval, processed)
if rawval == processed then
return msg
else
return ("%s (processed value %s)"):format(msg, dump_if_unusual(processed))
end
end
-- Generate the appropriate error-signaling function given parameter value `val` and name `name`. If `name` is already
-- a function, it is just returned; otherwise a function is generated and returned that displays the passed-in messaeg
-- along with the parameter's name and value.
local function make_parse_err(val, name)
if type(name) == "function" then
return name
else
return function(msg)
error(("%s: parameter %s=%s"):format(msg, name, val))
end
end
end
-- A reimplementation of ipairs() for use in a single-variable for-loop (like with gsplit()) instead of a two-variable
-- for-loop (like with ipairs()). If we changed the return statement below to `return index, list[index]`, we'd get
-- ipairs() directly.
local function iterate_over_list(list)
local index, len = 0, #list
return function()
index = index + 1
if index <= len then
return list[index]
end
end
end
-- A helper function for use with `sublist`. It is an iterator function for use in a for-loop that returns split
-- elements of `val` using `sublist` (a Lua split pattern; boolean `true` to split on commas optionally surrounded by
-- whitespace; or a function to do the splitting, which is passed two values, the value to split and a function to
-- signal an error, and should return a list of the split elements). `name` is the parameter name or error-signaling
-- function passed into convert_val().
local function split_sublist(val, name, sublist)
sublist = sublist == true and "%s*,%s*" or sublist
if type(sublist) == "string" then
return gsplit(val, sublist)
elseif type(sublist) == "function" then
local retval = sublist(val, make_parse_err(val, name))
return iterate_over_list(retval)
else
error(('Internal error: Expected `sublist` to be of type "string" or "function" or boolean `true`, but saw %s'):
format(dump(sublist)))
end
end
-- For parameter named `name` with value `val` and param spec `param`, if the `set` field is specified, verify that the
-- value is one of the one specified in `set`, and throw an error otherwise. `name` is taken directly from the
-- corresponding parameter passed into convert_val() and may be a function to signal an error. Optional `typ` is a
-- string specifying the conversion type of `val` and is used for special-casing: If `typ` is "boolean", an internal
-- error is thrown (since `set` cannot be used in conjunction with booleans) and if `typ` is "number", no checking
-- happens because in this case `set` contains numbers and is checked inside the number conversion function itself,
-- after converting `val` to a number.
local function check_set(val, name, param, typ)
if typ == "boolean" then
error(('Internal error: Cannot use `set` with `type = "%s"`'):format(typ))
end
if typ == "number" then
-- Needs to be special cased because the check happens after conversion to numbers.
return
end
if not param.set[val] then
local list = {}
for k in pairs(param.set) do
insert(list, dump(k))
end
sort(list)
-- If the parameter is not required then put "or empty" at the end of the list, to avoid implying the parameter is actually required.
if not param.required then
insert(list, "empty")
end
convert_val_error(val, name, list)
end
end
local function convert_language(val, name, param, allow_etym)
local lang = require(languages_module)[param.method == "name" and "getByCanonicalName" or "getByCode"](val, nil, allow_etym, param.family)
if lang then
return lang
end
local list = {"language"}
local links = {"[[WT:LOL]]"}
if allow_etym then
insert(list, "etymology language")
insert(links, "[[WT:LOL/E]]")
end
if param.family then
insert(list, "family")
insert(links, "[[WT:LOF]]")
end
convert_val_error(val, name, concat_list(list, " or ") .. " " .. (param.method == "name" and "name" or "code"),
concat_list(links, " and "))
end
--[==[ func: export.convert_val(val, name, param)
Convert a parameter value according to the associated specs listed in the `params` table passed to
[[Module:parameters]]. `val` is the value to convert for a parameter whose name is `name` (used only in error messages).
`param` is the spec (the value part of the `params` table for the parameter). In place of passing in the parameter name,
`name` can be a function that throws an error, displaying the specified message along with the parameter name and value.
This function processes all the conversion-related fields in `param`, including `type`, `set`, `sublist`, `convert`,
etc. It returns the converted value.
]==]
local convert_val = setmetatable({
["boolean"] = function(val)
return yesno(val, true)
end,
["family"] = function(val, name, param)
return require(families_module)[param.method == "name" and "getByCanonicalName" or "getByCode"](val) or
convert_val_error(val, name, "family " .. (param.method == "name" and "name" or "code"), "[[WT:LOF]]")
end,
["labels"] = function(val, name, param)
-- FIXME: Should be able to pass in a parse_err function.
return require(labels_module).split_labels_on_comma(val)
end,
["references"] = function(val, name, param)
return require(references_module).parse_references(val, make_parse_err(val, name))
end,
["qualifier"] = function(val, name, param)
return {val}
end,
["language"] = function(val, name, param)
return convert_language(val, name, param, true)
end,
["full language"] = function(val, name, param)
return convert_language(val, name, param, false)
end,
["number"] = function(val, name, param)
if type(val) == "number" then
return val
end
-- Avoid converting inputs like "nan" or "inf".
val = tonumber(val:match("^[+%-]?%d+%.?%d*")) or convert_val_error(val, name, "number")
if param.set then
-- Don't pass in "number" here; otherwise no checking will happen.
check_set(val, name, param)
end
return val
end,
["script"] = function(val, name, param)
return require(scripts_module)[param.method == "name" and "getByCanonicalName" or "getByCode"](val) or
convert_val_error(val, name, "script " .. (param.method == "name" and "name" or "code"), "[[WT:LOS]]")
end,
["string"] = function(val, name, param)
return val
end,
["wikimedia language"] = function(val, name, param)
local fallback = param.method == "fallback"
local lang = require(wikimedia_languages_module)[fallback and "getByCodeWithFallback" or "getByCode"](val)
if lang then
return lang
end
local list = {"wikimedia language"}
if fallback then
insert(list, "language")
end
convert_val_error(val, name, concat_list(list, " or ") .. " code")
end,
}, {
__call = function(self, val, name, param)
local typ = param.type or "string"
local func, sublist = self[typ], param.sublist
if not func then
error("Internal error: " .. dump(typ) .. " is not a recognized parameter type.")
elseif sublist then
local retlist = {}
if type(val) ~= "string" then
error("Internal error: " .. dump(val) .. " is not a string.")
end
if param.convert then
local thisval, insval
local thisindex = 0
local parse_err
if type(name) == "function" then
-- We assume the passed-in error function in `name` already shows the parameter name and raw value.
parse_err = function(msg)
name(("%s: item #%s=%s"):format(msg_with_processed(msg, thisval, insval), thisindex,
thisval))
end
else
parse_err = function(msg)
error(("%s: item #%s=%s of parameter %s=%s"):format(msg_with_processed(msg, thisval, insval),
thisindex, thisval, name, val))
end
end
for v in split_sublist(val, name, sublist) do
thisval = v
thisindex = thisindex + 1
if param.set then
check_set(v, name, param, typ)
end
insval = func(v, name, param)
insert(retlist, param.convert(insval, parse_err))
end
else
for v in split_sublist(val, name, sublist) do
if param.set then
check_set(v, name, param, typ)
end
insert(retlist, func(v, name, param))
end
end
return retlist
else
if param.set then
check_set(val, name, param, typ)
end
local retval = func(val, name, param)
if param.convert then
local parse_err
if type(name) == "function" then
-- We assume the passed-in error function in `name` already shows the parameter name and raw value.
if retval == val then
-- This is an optimization to avoid creating a closure. The second arm works correctly even
-- when retval == val.
parse_err = name
else
parse_err = function(msg)
name(msg_with_processed(msg, val, retval))
end
end
else
parse_err = function(msg)
error(("%s: parameter %s=%s"):format(msg_with_processed(msg, val, retval), name, val))
end
end
retval = param.convert(retval, parse_err)
end
return retval
end
end
})
export.convert_val = convert_val -- used by [[Module:parameter utilities]]
local function process_error(fmt, ...)
local args = {...}
for i, val in ipairs(args) do
args[i] = dump(val)
end
if type(fmt) == "table" then
-- hacky signal that we're called from internal_process_error(), and not to omit stack frames
return error(fmt[1]:format(unpack(args)))
else
return error(fmt:format(unpack(args)), 3)
end
end
local function internal_process_error(fmt, ...)
fmt = "Internal error in `params` table: " .. fmt
process_error({fmt}, ...)
end
--[==[
Process arguments with a given list of parameters. Return a table containing the processed arguments. The `args`
parameter specifies the arguments to be processed; they are the arguments you might retrieve from
{frame:getParent().args} (the template arguments) or in some cases {frame.args} (the invocation arguments). The `params`
parameter specifies a list of valid parameters, and consists of a table. If an argument is encountered that is not in
the parameter table, an error is thrown.
The structure of the `params` table is as described above in the intro comment.
'''WARNING:''' The `params` table is destructively modified to save memory. Nonetheless, different keys can share the
same value objects in memory without causing problems.
The `return_unknown` parameter, if set to {true}, prevents the function from triggering an error when it comes across an
argument with a name that it doesn't recognise. Instead, the return value is a pair of values: the first is the
processed arguments as usual, while the second contains all the unrecognised arguments that were left unprocessed. This
allows you to do multi-stage processing, where the entire set of arguments that a template should accept is not known at
once. For example, an inflection-table might do some generic processing on some arguments, but then defer processing of
the remainder to the function that handles a specific inflectional type.
]==]
function export.process(args, params, return_unknown)
-- Process parameters for specific properties
local args_new = {}
local required = {}
local seen = {}
local patterns = {}
local names_with_equal_sign = {}
local list_from_index
for name, param in pairs(params) do
-- Populate required table, and make sure aliases aren't set to required.
if param.required then
if param.alias_of then
internal_process_error(
"Parameter %s is an alias of %s, but is also set as a required parameter. Only %s should be set as required.",
name, param.alias_of, name)
end
required[name] = true
end
-- Convert param.set from a list into a set.
-- `seen` prevents double-conversion if multiple parameter keys share the same param table.
local set = param.set
if set and not seen[param] then
param.set = list_to_set(set)
seen[param] = true
end
local alias = param.alias_of
if alias then
-- Check that the alias_of is set to a valid parameter.
if not params[alias] then
internal_process_error("Parameter %s is an alias of an invalid parameter.", name)
end
-- Check that all the parameters in params are in the form Scribunto normalizes input argument keys into (e.g. 1 not "1", "foo" not " foo "). Otherwise, this function won't be able to normalize the input arguments in the expected way.
local normalized = scribunto_param_key(alias)
if alias ~= normalized then
internal_process_error(
"Parameter %s (a " .. type(alias) .. ") given in the alias_of field of parameter %s is not a normalized Scribunto parameter. Should be %s (a " .. type(normalized) .. ").",
alias, name, normalized)
-- Aliases can't be lists unless the canonical parameter is also a list.
elseif param.list and not params[alias].list then
internal_process_error(
"The list parameter %s is set as an alias of %s, which is not a list parameter.", name, alias)
-- Aliases can't be aliases of other aliases.
elseif params[alias].alias_of then
internal_process_error(
"Alias_of cannot be set to another alias: parameter %s is set as an alias of %s, which is in turn an alias of %s. Set alias_of for %s to %s.",
name, alias, params[alias].alias_of, name, params[alias].alias_of)
end
end
local normalized = scribunto_param_key(name)
if name ~= normalized then
internal_process_error(
"Parameter %s (a " .. type(name) .. ") is not a normalized Scribunto parameter. Should be %s (a " ..
type(normalized) .. ").",
name, normalized)
end
if param.list then
if not param.alias_of then
local key = name
if type(name) == "string" then
key = gsub(name, "\1", "")
end
-- _list is used as a temporary flag.
args_new[key] = {maxindex = 0, _list = param.list}
end
if type(param.list) == "string" then
-- If the list property is a string, then it represents the name
-- to be used as the prefix for list items. This is for use with lists
-- where the first item is a numbered parameter and the
-- subsequent ones are named, such as 1, pl2, pl3.
save_pattern(name, param.list, patterns)
elseif type(name) == "number" then
if list_from_index then
internal_process_error(
"Only one numeric parameter can be a list, unless the list property is a string.")
end
-- If the name is a number, then all indexed parameters from
-- this number onwards go in the list.
list_from_index = name
else
save_pattern(name, name, patterns)
end
if match(name, "\1") then
insert(names_with_equal_sign, name)
end
end
end
--Process required changes to `params`.
for i = 1, #names_with_equal_sign do
local name = names_with_equal_sign[i]
params[gsub(name, "\1", "")] = params[name]
params[name] = nil
end
-- Process the arguments
local args_unknown = {}
local max_index
for name, val in pairs(args) do
local orig_name, raw_type, index, normalized = name, type(name)
if raw_type == "number" then
if list_from_index ~= nil and name >= list_from_index then
index = name - list_from_index + 1
name = list_from_index
end
else
-- Does this argument name match a pattern?
for pattern, pname in pairs(patterns) do
index = match(name, pattern)
-- It matches, so store the parameter name and the
-- numeric index extracted from the argument name.
if index then
index = tonumber(index)
name = pname
break
end
end
end
local param = params[name]
if param and param.require_index then
-- Disallow require_index for numeric parameter names, as this doesn't make sense.
if raw_type == "number" then
internal_process_error("Cannot set require_index for numeric parameter %s.", name)
-- If a parameter without the trailing index was found, and
-- require_index is set on the param, set the param to nil to treat it
-- as if it isn't recognized.
elseif not index then
param = nil
end
end
-- If the argument is not in the list of parameters, trigger an error.
-- return_unknown suppresses the error, and stores it in a separate list instead.
if not param then
if return_unknown then
args_unknown[name] = val
else
process_error("Parameter %s is not used by this template.", name)
end
else
-- Check that separate_no_index is not being used with a numeric parameter.
if param.separate_no_index then
if raw_type == "number" then
internal_process_error("Cannot set separate_no_index for numeric parameter %s.", name)
elseif type(param.alias_of) == "number" then
internal_process_error(
"Cannot set separate_no_index for parameter %s, as it is an alias of numeric parameter %s.",
name, param.alias_of)
end
end
-- If no index was found, use 1 as the default index.
-- This makes list parameters like g, g2, g3 put g at index 1.
-- If `separate_no_index` is set, then use 0 as the default instead.
if param.list then
index = index or param.separate_no_index and 0 or 1
end
-- Normalize to the canonical parameter name. If it's a list, but the alias is not, then determine the index.
local raw_name = param.alias_of
if param.alias_of then
raw_type = type(raw_name)
if raw_type == "number" then
if params[raw_name].list then
index = index or param.separate_no_index and 0 or 1
normalized = raw_name + index - 1
else
normalized = raw_name
end
name = raw_name
else
name = gsub(raw_name, "\1", "")
if params[name].list then
index = index or param.separate_no_index and 0 or 1
end
if not index or index == 0 then
normalized = name
elseif name == raw_name then
normalized = name .. index
else
normalized = gsub(raw_name, "\1", index)
end
end
else
normalized = orig_name
end
-- Remove leading and trailing whitespace unless allow_whitespace is true.
if not param.allow_whitespace then
val = trim(val)
end
-- Empty string is equivalent to nil unless allow_empty is true.
if val == "" and not param.allow_empty then
val = nil
-- Track empty parameters, unless (1) allow_empty is set or (2) they're numbered parameters where a higher numbered parameter is also in use (e.g. track {{l|en|term|}}, but not {{l|en||term}}).
if raw_type == "number" and not max_index then
-- Find the highest numbered parameter that's in use/an empty string, as we don't want parameters like 500= to mean we can't track any empty parameters with a lower index than 500.
local n = 0
while args[n + 1] do
n = n + 1
end
max_index = 0
for n = n, 1, -1 do
if args[n] ~= "" then
max_index = n
break
end
end
end
if raw_type ~= "number" or name > max_index then
-- Disable this for now as it causes slowdowns on large pages like [[a]].
-- track("empty parameter")
end
end
-- Can't use "if val" alone, because val may be a boolean false.
if val ~= nil then
-- Convert to proper type if necessary.
val = convert_val(val, orig_name, params[raw_name] or param)
-- Mark it as no longer required, as it is present.
required[name] = nil
-- Store the argument value.
if index then
-- If the parameter is duplicated, throw an error.
if args_new[name][index] ~= nil then
process_error(
"Parameter %s has been entered more than once. This is probably because a list parameter has been entered without an index and with index 1 at the same time, or because a parameter alias has been used.",
normalized)
end
args_new[name][index] = val
-- Store the highest index we find.
args_new[name].maxindex = max(index, args_new[name].maxindex)
if args_new[name][0] ~= nil then
args_new[name].default = args_new[name][0]
if args_new[name].maxindex == 0 then
args_new[name].maxindex = 1
end
args_new[name][0] = nil
end
if params[name].list then
-- Don't store index 0, as it's a proxy for the default.
if index > 0 then
args_new[name][index] = val
-- Store the highest index we find.
args_new[name].maxindex = max(index, args_new[name].maxindex)
end
else
args_new[name] = val
end
else
-- If the parameter is duplicated, throw an error.
if args_new[name] ~= nil then
process_error(
"Parameter %s has been entered more than once. This is probably because a parameter alias has been used.",
normalized)
end
if not param.alias_of then
args_new[name] = val
else
if params[param.alias_of].list then
args_new[param.alias_of][1] = val
-- Store the highest index we find.
args_new[param.alias_of].maxindex = max(1, args_new[param.alias_of].maxindex)
else
args_new[param.alias_of] = val
end
end
end
end
end
end
-- Remove holes in any list parameters if needed.
for name, val in pairs(args_new) do
if type(val) == "table" then
local listname = val._list
if listname then
if params[name].disallow_holes then
local highest = 0
for num, _ in pairs(val) do
if type(num) == "number" and num > 0 and num < huge and floor(num) == num then
highest = max(highest, num)
end
end
for i = 1, highest do
if val[i] == nil then
if type(listname) == "string" then
listname = dump(listname)
elseif type(name) == "number" then
i = i + name - 1 -- Absolute index.
listname = "numeric"
else
listname = dump(name)
end
process_error(
"Item %s in the list of " .. listname .. " parameters cannot be empty, because the list must be contiguous.",
i)
end
end
-- Some code depends on only numeric params being present
-- when no holes are allowed (e.g. by checking for the
-- presence of arguments using next()), so remove
-- `maxindex`.
val.maxindex = nil
elseif not params[name].allow_holes then
args_new[name] = remove_holes(val)
end
end
end
end
-- Determine whether this is a template page. For these pages, normally required params aren't required, and the
-- `template_default` key supplies the default value only for these pages. Template documentation pages don't count
-- because we want template invocations on those pages to behave like mainspace template invocations.
local title_obj = mw.title.getCurrentTitle()
local is_template_page = title_obj.namespace == 10 and not title_obj.text:find("/documentation$")
-- Handle defaults.
for name, param in pairs(params) do
local default_val
-- If both `template_default` and `default` are given, `template_default` takes precedence, but only on
-- template pages. This lets you specify a different default as the template page example.
if is_template_page then
default_val = param.template_default
end
if default_val == nil then
default_val = param.default
end
if default_val ~= nil then
local arg_new = args_new[name]
if type(arg_new) == "table" and arg_new._list then
if arg_new[1] == nil then
arg_new[1] = convert_val(default_val, name, param)
end
if arg_new.maxindex == 0 then
arg_new.maxindex = 1
end
arg_new._list = nil
elseif arg_new == nil then
args_new[name] = convert_val(default_val, name, param)
end
end
end
-- The required table should now be empty.
-- If any entry remains, trigger an error, unless we're on a template page.
if not is_template_page then
local list = {}
for name in pairs(required) do
insert(list, dump(name))
end
local n = #list
if n > 0 then
process_error("Parameter" .. (
n == 1 and (" " .. list[1] .. " is") or
("s " .. concat_list(list, " and ", true) .. " are")
) .. " required.")
end
end
-- Remove the temporary _list flag.
for _, arg_new in pairs(args_new) do
if type(arg_new) == "table" then
arg_new._list = nil
end
end
if return_unknown then
return args_new, args_unknown
else
return args_new
end
end
return export