-- <nowiki>
--------------------------------------------------------------------------------
-- An inexpensive alternative to {{#ifexist}} which looks for a given module,
-- and returns one of two values depending on whether it was found.
--
-- Syntax:
-- {{#invoke:Existsmod|main|<module-name>|<value-if-found>|<value-if-missing>}}
--------------------------------------------------------------------------------
local p = {}

local checkType = require("libraryUtil").checkType
local normalize = require("Dev:NormalizeModuleName")
local getArgs = require("Dev:Arguments").getArgs

function p.module_exists(name, foundVal, missingVal)
    checkType("Dev:Existsmod", 1, name, "string", true)

    if name then
        name = table.concat{normalize(name)}

        -- if package.loaded[name] then
        --     return foundVal
        -- else
            local _, val = pcall(package.loaders[2], name)

            if type(val) == "function" or type(val) == "string" then
                return foundVal 
            end
        -- end
    end

    return missingVal
end

function p.main(frame)
    local args = getArgs(frame)

    return p.module_exists(args[1], args[2], args[3])
end

return p
 
-- </nowiki>
-- (Add categories here.)