Module:Cartesian with comma

This module computes and returns the cartesian product of multiple input sets (i.e., lists of strings), and then formats and combines the results into a single output string. Because this module was original developed to deal with locations, if a value in the first set contains a comma, a comma will be added to the end of that value before it is combined with a value from the second set.

Example

It is called by {{Combine categories}} to create category names from a list of locations and a list of topics.

{{#invoke:Cartesian categories|combine
    | {{{location}}}
    | {{lc:{{{locality_subjects}}}}}
    | format = [[Category:%s %s]]
}}

Input:

{{Combine categories
|location=Bucks County, Pennsylvania;Chester County, Pennsylvania;Pennsylvania
|locality_subjects=Court records;Probate records;Vital records
}}

Output:

[[Category:Pennsylvania court records]]
[[Category:Pennsylvania probate records]]
[[Category:Pennsylvania vital records]]
[[Category:Bucks County, Pennsylvania, court records]]
[[Category:Bucks County, Pennsylvania, probate records]]
[[Category:Bucks County, Pennsylvania, vital records]]
[[Category:Chester County, Pennsylvania, court records]]
[[Category:Chester County, Pennsylvania, probate records]]
[[Category:Chester County, Pennsylvania, vital records]]

Acknowledgements

Original code provided by Alexander Mashin.

local remove, insert, concat = table.remove, table.insert, table.concat
local split, trim = mw.text.split, mw.text.trim
local clone = mw.clone

local function cartesian (sets)
    local product = {}
    local set = remove (sets)
    if #sets == 0 then
        for _, item in ipairs (set) do
            insert (product, { item })
        end
        return product
    end
    for __, first in ipairs (cartesian (sets)) do
        for _, second in ipairs (set) do
            insert (product, clone (first))
            insert (product [#product], second)
        end
    end
    return product
end

local function format_array (array, format, separator)
    local formatted = {}
    for _, combination in ipairs (array) do
        insert (formatted, format:format (unpack (combination)))
    end
    return concat (formatted, separator)
end
        
return {
combine = function (frame)
    local sets = {}
    local delimiter = frame.args.delimiter or ';'
    local splitter = '%s*' .. delimiter .. '%s*'
    local default_format = {}
    for i, list in ipairs (frame.args) do
        local items = split (trim (list), splitter)
        -- If this is the first set, add a comma to items that contain a comma
        if i == 1 then
            for j, item in ipairs(items) do
                if item:find(',') then
                    items[j] = item .. ','
                end
            end
        end
        sets[#sets + 1] = items
        insert (default_format, '%s')
    end
    local format = frame.args.format or concat (default_format, ', ')
    local separator = frame.args.separator or '\n'
    return format_array (cartesian (sets), format, separator)
end
}

Example

See also

Acknowledgements