Module:Params

Documentation for this module may be created at Module:Params/doc

	---                                        ---
	---     LOCAL ENVIRONMENT                  ---
	---    ________________________________    ---
	---                                        ---


-- Special user-given keywords (functions and modifiers MUST avoid these names)
local mkeywords = {
--	['pattern'] = false,
	['plain'] = true,
	['or'] = 0
}


-- Memory slots
local memoryslots = {
	i = 'itersep',
	l = 'lastsep',
	p = 'pairsep',
	h = 'header',
	f = 'footer',
	n = 'ifngiven'
}


-- Directive that can only be invoked as first arguments
local firstposonly = {
	new = 'modifier',
	self = 'function',
}


-- The private table of functions
local library = {}


-- Return a copy or a reference to a table
local function copy_or_ref_table(src, refonly)
	if refonly then return src end
	newtab = {}
	for key, val in pairs(src) do newtab[key] = val end
	return newtab
end


-- Prepare the context
local function context_new(frame)
	local ctx = {}
	ctx.luaname = 'Module:Params'	--[[ or `frame:getTitle()` ]]--
	ctx.iterfunc = pairs
	ctx.frame = frame:getParent()
	return ctx
end


-- Prepare the context
local function context_init(frame, funcname, refpipe, refparams)
	local ctx = context_new(frame)
	ctx.pipe = copy_or_ref_table(frame.args, refpipe)
	ctx.params = copy_or_ref_table(ctx.frame.args, refparams)
	return funcname(ctx)
end


-- Move to the next action within the user-given list
local function context_iterate(ctx, n_forward)
	local nextfn
	if ctx.pipe[n_forward] ~= nil then
		nextfn = ctx.pipe[n_forward]:match'^%s*(.*%S)'
	end
	if nextfn == nil then
		error(ctx.luaname .. ': You must specify a function to call', 0)
	end
	if library[nextfn] == nil then
		if firstposonly[nextfn] == nil then
			error(ctx.luaname .. ': The function ‘' .. nextfn ..
				'’ does not exist', 0)
		else
			error(ctx.luaname .. ': The ‘' .. nextfn .. '’ ' ..
				firstposonly[nextfn] ..
				' can only be invoked in first position', 0)
		end
	end
	for idx = n_forward, 1, -1 do table.remove(ctx.pipe, idx) end
	return library[nextfn](ctx)
end


-- Concatenate the numerical keys from the table of parameters to the numerical
-- keys from the table of options; non-numerical keys from the table of options
-- will prevail over colliding non-numerical keys from the table of parameters
local function concat_params(ctx)
	local shift = table.maxn(ctx.pipe)
	local newargs = {}
	if ctx.subset == 1 then
		-- We need only the sequence
		for key, val in ipairs(ctx.params) do
			newargs[key + shift] = val
		end
	else
		if ctx.subset == -1 then
			for key, val in ipairs(ctx.params) do
				ctx.params[key] = nil
			end
		end
		for key, val in pairs(ctx.params) do
			if type(key) == 'number' then
				newargs[key + shift] = val
			else
				newargs[key] = val
			end
		end
	end
	for key, val in pairs(ctx.pipe) do newargs[key] = val end
	return newargs
end


-- Helper function for `string.gsub()` (for managing zero-padded numbers)
function zero_padded(str)
	return ("%03d%s"):format(#str, str)
end


-- Helper function for `table.sort()` (for natural sorting)
function natural_sort(var1, var2)
	return tostring(var1):gsub("%d+", zero_padded) <
		tostring(var2):gsub("%d+", zero_padded)
end


-- Flush the parameters by calling a custom function for each value (after this
-- function has been invoked `ctx.params` will no longer be usable)
local function flush_params(ctx, fn)
	local tbl = ctx.params
	if ctx.subset == 1 then
		for key, val in ipairs(tbl) do fn(key, val) end
		return
	end
	if ctx.subset == -1 then
		for key, val in ipairs(tbl) do tbl[key] = nil end
	end
	if ctx.dosort then
		local nums = {}
		local words = {}
		local nlen = 0
		local wlen = 0
		for key, val in pairs(tbl) do
			if type(key) == 'number' then
				nlen = nlen + 1
				nums[nlen] = key
			else
				wlen = wlen + 1
				words[wlen] = key
			end

		end
		table.sort(nums)
		table.sort(words, natural_sort)
		for idx = 1, nlen do fn(nums[idx], tbl[nums[idx]]) end
		for idx = 1, wlen do fn(words[idx], tbl[words[idx]]) end
		return
	end
	if ctx.subset ~= -1 then
		for key, val in ipairs(tbl) do
			fn(key, val)
			tbl[key] = nil
		end
	end
	for key, val in pairs(tbl) do fn(key, val) end
end


-- Parse the arguments of the `with_*_matching` class of modifiers
local function parse_match_args(opts, ptns, fname)
	local state = 0
	local cnt = 1
	local keyw
	local nptns = 0
	for _, val in ipairs(opts) do
		if state == 0 then
			nptns = nptns + 1
			ptns[nptns] = { val, false }
			state = -1
		else
			keyw = val:match'^%s*(.*%S)'
			if keyw == nil or mkeywords[keyw] == nil then break
			else
				state = mkeywords[keyw]
				if state ~= 0 then ptns[nptns][2] = state end
			end
		end
		cnt = cnt + 1
	end
	if state == 0 then error(ctx.luaname .. ', ‘' .. fname .. '’: No pattern was given', 0) end
	return cnt
end


-- Remove numerical arguments (not necessarily sequential ones)
function purge_args(tbl, offset, length)
	local cache = {}
	local pshift
	local nshift
	if offset > 0 then
		pshift = length
		nshift = 0
	elseif offset + length > 1 then
		pshift = offset + length - 1
		nshift = 1 - offset
	else
		pshift = 0
		nshift = length
	end
	for key, val in pairs(tbl) do
		if type(key) == 'number' then
			if key > 0 and key >= offset then
				if key >= offset + length then
					cache[key - pshift] = val
				end
				tbl[key] = nil
			elseif key < 1 and key < offset + length then
				if key < offset then
					cache[key + nshift] = val
				end
				tbl[key] = nil
			end
		end
	end
	for key, val in pairs(cache) do tbl[key] = val end
end



	--[[ Library's modifiers ]]--
	--------------------------------


-- See iface.sequential()
library.sequential = function(ctx)
	if ctx.subset == -1 then error(ctx.luaname .. ': The two directives ‘non-sequential’ and ‘sequential’ are in contradiction with each other', 0) end
	if ctx.dosort then error(ctx.luaname .. ': The ‘all_sorted’ directive is redundant when followed by ‘sequential’', 0) end
	ctx.iterfunc = ipairs
	ctx.subset = 1
	return context_iterate(ctx, 1)
end


-- See iface['non-sequential']()
library['non-sequential'] = function(ctx)
	if ctx.subset == 1 then error(ctx.luaname .. ': The two directives ‘sequential’ and ‘non-sequential’ are in contradiction with each other', 0) end
	ctx.iterfunc = pairs
	ctx.subset = -1
	return context_iterate(ctx, 1)
end


-- See iface.all_sorted()
library.all_sorted = function(ctx)
	if ctx.subset == 1 then error(ctx.luaname .. ': The ‘all_sorted’ directive is redundant after ‘sequential’', 0) end
	ctx.dosort = true
	return context_iterate(ctx, 1)
end


-- See iface.setting()
library.setting = function(ctx)
	local opts = ctx.pipe
	local cmd
	if opts[1] ~= nil then
		cmd = opts[1]:gsub('%s+', ''):gsub('/+', '/'):match'^/*(.*[^/])'
	end
	if cmd == nil then error(ctx.luaname .. ', ‘setting’: No directive was given', 0) end
	local sep = string.byte('/')
	local argc = 2
	local dest = {}
	local vname
	local chr
	for idx = 1, #cmd do
		chr = cmd:byte(idx)
		if chr == sep then
			for key, val in ipairs(dest) do
				ctx[val] = opts[argc]
				dest[key] = nil
			end
			argc = argc + 1
		else
			vname = memoryslots[string.char(chr)]
			if vname == nil then error(ctx.luaname .. ', ‘setting’: Unknown slot "' ..
				string.char(chr) .. '"', 0) end
			table.insert(dest, vname)
		end
	end
	for key, val in ipairs(dest) do ctx[val] = opts[argc] end
	return context_iterate(ctx, argc + 1)
end


-- See iface.squeezing()
library.squeezing = function(ctx)
	local tbl = ctx.params
	local store = {}
	local indices = {}
	local newlen = 0
	for key, val in pairs(tbl) do
		if type(key) == 'number' then
			newlen = newlen + 1
			indices[newlen] = key
			store[key] = val
			tbl[key] = nil
		end
	end
	table.sort(indices)
	for idx = 1, newlen do tbl[idx] = store[indices[idx]] end
	return context_iterate(ctx, 1)
end


-- See iface.cutting()
library.cutting = function(ctx)
	local lcut = tonumber(ctx.pipe[1])
	if lcut == nil then error(ctx.luaname .. ', ‘cutting’: Left cut must be a number', 0) end
	local rcut = tonumber(ctx.pipe[2])
	if rcut == nil then error(ctx.luaname .. ', ‘cutting’: Right cut must be a number', 0) end
	local tbl = ctx.params
	local len = #tbl
	if lcut < 0 then lcut = len + lcut end
	if rcut < 0 then rcut = len + rcut end
	local tot = lcut + rcut
	if tot > 0 then
		local cache = {}
		if tot >= len then
			for key in ipairs(tbl) do tbl[key] = nil end
			tot = len
		else
			for idx = len - rcut + 1, len, 1 do tbl[idx] = nil end
			for idx = 1, lcut, 1 do tbl[idx] = nil end
		end
		for key, val in pairs(tbl) do
			if type(key) == 'number' and key > 0 then
				if key > len then
					cache[key - tot] = val
				else
					cache[key - lcut] = val
				end
				tbl[key] = nil
			end
		end
		for key, val in pairs(cache) do tbl[key] = val end
	end
	return context_iterate(ctx, 3)
end


-- See iface.cropping()
library.cropping = function(ctx)
	local lcut = tonumber(ctx.pipe[1])
	if lcut == nil then error(ctx.luaname .. ', ‘cropping’: Left crop must be a number', 0) end
	local rcut = tonumber(ctx.pipe[2])
	if rcut == nil then error(ctx.luaname .. ', ‘cropping’: Right crop must be a number', 0) end
	local tbl = ctx.params
	local nmin
	local nmax
	for key in pairs(tbl) do
		if type(key) == 'number' then
			if nmin == nil then
				nmin = key
				nmax = key
			elseif key > nmax then nmax = key
			elseif key < nmin then nmin = key
			end
		end
	end
	if nmin ~= nil then
		local len = nmax - nmin + 1
		if lcut < 0 then lcut = len + lcut end
		if rcut < 0 then rcut = len + rcut end
		if lcut + rcut - len > -1 then
			for key in pairs(tbl) do
				if type(key) == 'number' then tbl[key] = nil end
			end
		elseif lcut + rcut > 0 then
			for idx = nmax - rcut + 1, nmax, 1 do tbl[idx] = nil end
			for idx = nmin, nmin + lcut - 1, 1 do tbl[idx] = nil end
			local lshift = nmin + lcut - 1
			if lshift > 0 then
				for idx = lshift + 1, nmax, 1 do
					tbl[idx - lshift] = tbl[idx]
					tbl[idx] = nil
				end
			end
		end
	end
	return context_iterate(ctx, 3)
end


-- See iface.purging()
library.purging = function(ctx)
	local first = tonumber(ctx.pipe[1])
	if first == nil then error(ctx.luaname .. ', ‘purging’: Start offset must be a number', 0) end
	local size = tonumber(ctx.pipe[2])
	if size == nil then error(ctx.luaname .. ', ‘purging’: Length must be a number', 0) end
	local tbl = ctx.params
	if size < 1 then
		size = size + table.maxn(tbl)
		if first > size then return context_iterate(ctx, 3) end
		size = size - first + 1
	end
	purge_args(tbl, first, size)
	return context_iterate(ctx, 3)
end


-- See iface.backpurging()
library.backpurging = function(ctx)
	local last = tonumber(ctx.pipe[1])
	if last == nil then error(ctx.luaname .. ', ‘backpurging’: Start offset must be a number', 0) end
	local size = tonumber(ctx.pipe[2])
	if size == nil then error(ctx.luaname .. ', ‘backpurging’: Length must be a number', 0) end
	local first
	local tbl = ctx.params
	if size > 0 then
		first = last - size + 1
	else
		for key in pairs(tbl) do
			if type(key) == 'number' and (first == nil or
				key < first) then first = key end
		end
		if first == nil then return context_iterate(ctx, 3) end
		first = first - size
		if last < first then return context_iterate(ctx, 3) end
		size = last - first + 1
	end
	purge_args(ctx.params, first, size)
	return context_iterate(ctx, 3)
end


-- See iface.reversing()
library.reversing = function(ctx)
	local tbl = ctx.params
	local reversed = {}
	local nmax
	local nmin
	for key, val in pairs(tbl) do
		if type(key) == 'number' then
			reversed[key] = val
			tbl[key] = nil
			if nmax == nil then
				nmax = key
				nmin = key
			elseif key > nmax then nmax = key
			elseif key < nmin then nmin = key
			end
		end
	end
	for key, val in pairs(reversed) do
		tbl[nmax + nmin - key] = val
	end
	return context_iterate(ctx, 1)
end


-- See iface.swapping()
--[[
library.swapping = function(ctx)
	local tbl = ctx.params
	local cache = {}
	local nsize = 0
	local tmp
	for key in pairs(tbl) do
		if type(key) == 'number' then
			nsize = nsize + 1
			cache[nsize] = key
		end
	end
	table.sort(cache)
	for idx = math.floor(nsize / 2), 1, -1 do
		tmp = tbl[cache[idx] ]
		tbl[cache[idx] ] = tbl[cache[nsize - idx + 1] ]
		tbl[cache[nsize - idx + 1] ] = tmp
	end
	return context_iterate(ctx, 1)
end
]]--


-- See iface.with_name_matching()
library.with_name_matching = function(ctx)
	local tbl = ctx.params
	local patterns = {}
	local argc = parse_match_args(ctx.pipe, patterns, 'with_name_matching')
	local nomatch
	for key in pairs(tbl) do
		nomatch = true
		for _, ptn in ipairs(patterns) do
			if string.find(key, ptn[1], 1, ptn[2]) then
				nomatch = false
				break
			end
		end
		if nomatch then tbl[key] = nil end
	end
	return context_iterate(ctx, argc)
end


-- See iface.with_name_not_matching()
library.with_name_not_matching = function(ctx)
	local tbl = ctx.params
	local patterns = {}
	local argc = parse_match_args(ctx.pipe, patterns,
		'with_name_not_matching')
	local yesmatch
	for key in pairs(tbl) do
		yesmatch = true
		for _, ptn in ipairs(patterns) do
			if not string.find(key, ptn[1], 1, ptn[2]) then
				yesmatch = false
				break
			end
		end
		if yesmatch then tbl[key] = nil end
	end
	return context_iterate(ctx, argc)
end


-- See iface.with_value_matching()
library.with_value_matching = function(ctx)
	local tbl = ctx.params
	local patterns = {}
	local argc = parse_match_args(ctx.pipe, patterns,
		'with_value_matching')
	local nomatch
	for key, val in pairs(tbl) do
		nomatch = true
		for _, ptn in ipairs(patterns) do
			if string.find(val, ptn[1], 1, ptn[2]) then
				nomatch = false
				break
			end
		end
		if nomatch then tbl[key] = nil end
	end
	return context_iterate(ctx, argc)
end


-- See iface.with_value_not_matching()
library.with_value_not_matching = function(ctx)
	local tbl = ctx.params
	local patterns = {}
	local argc = parse_match_args(ctx.pipe, patterns,
		'with_value_not_matching')
	local yesmatch
	for key, val in pairs(tbl) do
		yesmatch = true
		for _, ptn in ipairs(patterns) do
			if not string.find(val, ptn[1], 1, ptn[2]) then
				yesmatch = false
				break
			end
		end
		if yesmatch then tbl[key] = nil end
	end
	return context_iterate(ctx, argc)
end


-- See iface.trimming_values()
library.trimming_values = function(ctx)
	local tbl = ctx.params
	for key, val in pairs(tbl) do tbl[key] = val:match'^%s*(.-)%s*$' end
	return context_iterate(ctx, 1)
end


-- See iface.mapping_by_calling()
library.mapping_by_calling = function(ctx)
	local opts = ctx.pipe
	local tname
	if opts[1] ~= nil then tname = opts[1]:match'^%s*(.*%S)' end
	if tname == nil then error(ctx.luaname .. ', ‘mapping_by_calling’: No template name was provided', 0) end
	local nargs
	local margs = {}
	local tmp = tonumber(opts[2])
	if tmp == nil then
		nargs = 1
	elseif tmp < 1 then
		nargs = 2
	else
		nargs = tmp + 2
		for idx = 3, nargs do margs[idx] = opts[idx] end
	end
	local model = { title = tname, args = margs }
	local tbl = ctx.params
	for key, val in pairs(tbl) do
		margs[1] = key
		margs[2] = val
		tbl[key] = ctx.frame:expandTemplate(model)
	end
	return context_iterate(ctx, nargs + 1)
end


-- See iface.mapping_by_invoking()
library.mapping_by_invoking = function(ctx)
	local opts = ctx.pipe
	local mname
	local fname
	if opts[1] ~= nil then mname = opts[1]:match'^%s*(.*%S)' end
	if mname == nil then error(ctx.luaname .. ', ‘mapping_by_invoking’: No module name was provided', 0) end
	if opts[2] ~= nil then fname = opts[2]:match'^%s*(.*%S)' end
	if fname == nil then error(ctx.luaname .. ', ‘mapping_by_invoking’: No function name was provided', 0) end
	local nargs
	local margs = {}
	local tmp = tonumber(opts[3])
	if tmp == nil then
		nargs = 2
	elseif tmp < 1 then
		nargs = 3
	else
		nargs = tmp + 3
		for idx = 4, nargs do margs[idx - 1] = opts[idx] end
	end
	local model = { title = 'Module:' .. mname, args = margs }
	local mfunc = require(model.title)[fname]
	local tbl = ctx.params
	for key, val in pairs(tbl) do
		margs[1] = key
		margs[2] = val
		tbl[key] = mfunc(ctx.frame:newChild(model))
	end
	return context_iterate(ctx, nargs + 1)
end


-- See iface.mapping_blindly_by_calling()
library.mapping_blindly_by_calling = function(ctx)
	local opts = ctx.pipe
	local tname
	if opts[1] ~= nil then tname = opts[1]:match'^%s*(.*%S)' end
	if tname == nil then error(ctx.luaname .. ', ‘mapping_blindly_by_calling’: No template name was provided', 0) end
	local nargs
	local margs = {}
	local tmp = tonumber(opts[2])
	if tmp == nil then
		nargs = 1
	elseif tmp < 1 then
		nargs = 2
	else
		nargs = tmp + 2
		for idx = 3, nargs do margs[idx - 1] = opts[idx] end
	end
	local model = { title = tname, args = margs }
	local tbl = ctx.params
	for key, val in pairs(tbl) do
		margs[1] = val
		tbl[key] = ctx.frame:expandTemplate(model)
	end
	return context_iterate(ctx, nargs + 1)
end


-- See iface.mapping_blindly_by_invoking()
library.mapping_blindly_by_invoking = function(ctx)
	local opts = ctx.pipe
	local mname
	local fname
	if opts[1] ~= nil then mname = opts[1]:match'^%s*(.*%S)' end
	if mname == nil then error(ctx.luaname .. ', ‘mapping_blindly_by_invoking’: No module name was provided', 0) end
	if opts[2] ~= nil then fname = opts[2]:match'^%s*(.*%S)' end
	if fname == nil then error(ctx.luaname .. ', ‘mapping_blindly_by_invoking’: No function name was provided', 0) end
	local nargs
	local margs = {}
	local tmp = tonumber(opts[3])
	if tmp == nil then
		nargs = 2
	elseif tmp < 1 then
		nargs = 3
	else
		nargs = tmp + 3
		for idx = 4, nargs do margs[idx - 2] = opts[idx] end
	end
	local model = { title = 'Module:' .. mname, args = margs }
	local mfunc = require(model.title)[fname]
	local tbl = ctx.params
	for key, val in pairs(tbl) do
		margs[1] = val
		tbl[key] = mfunc(ctx.frame:newChild(model))
	end
	return context_iterate(ctx, nargs + 1)
end


-- See iface.renaming_blindly_by_calling()
library.renaming_blindly_by_calling = function(ctx)
	local opts = ctx.pipe
	local tname
	if opts[1] ~= nil then tname = opts[1]:match'^%s*(.*%S)' end
	if tname == nil then error(ctx.luaname .. ', ‘renaming_blindly_by_calling’: No template name was provided', 0) end
	local nargs
	local margs = {}
	local tmp = tonumber(opts[2])
	if tmp == nil then
		nargs = 1
	elseif tmp < 1 then
		nargs = 2
	else
		nargs = tmp + 2
		for idx = 3, nargs do margs[idx - 1] = opts[idx] end
	end
	local model = { title = tname, args = margs }
	local tbl = {}
	for key, val in pairs(ctx.params) do
		margs[1] = key
		tbl[ctx.frame:expandTemplate(model)] = val
	end
	ctx.params = tbl
	return context_iterate(ctx, nargs + 1)
end


-- See iface.renaming_blindly_by_invoking()
library.renaming_blindly_by_invoking = function(ctx)
	local opts = ctx.pipe
	local mname
	local fname
	if opts[1] ~= nil then mname = opts[1]:match'^%s*(.*%S)' end
	if mname == nil then error(ctx.luaname .. ', ‘renaming_blindly_by_invoking’: No module name was provided', 0) end
	if opts[2] ~= nil then fname = opts[2]:match'^%s*(.*%S)' end
	if fname == nil then error(ctx.luaname .. ', ‘renaming_blindly_by_invoking’: No function name was provided', 0) end
	local nargs
	local margs = {}
	local tmp = tonumber(opts[3])
	if tmp == nil then
		nargs = 2
	elseif tmp < 1 then
		nargs = 3
	else
		nargs = tmp + 3
		for idx = 4, nargs do margs[idx - 2] = opts[idx] end
	end
	local model = { title = 'Module:' .. mname, args = margs }
	local mfunc = require(model.title)[fname]
	local tbl = {}
	for key, val in pairs(ctx.params) do
		margs[1] = key
		tbl[mfunc(ctx.frame:newChild(model))] = val
	end
	ctx.params = tbl
	return context_iterate(ctx, nargs + 1)
end



	--[[ Library's functions ]]--
	------------------------------------


-- See iface.count()
library.count = function(ctx)
	local count = 0
	for _ in ctx.iterfunc(ctx.params) do count = count + 1 end
	if ctx.subset == -1 then count = count - #ctx.params end
	return count
end


-- See iface.concat_and_call()
library.concat_and_call = function(ctx)
	local opts = ctx.pipe
	local tname
	if opts[1] ~= nil then tname = opts[1]:match'^%s*(.*%S)' end
	if tname == nil then error(ctx.luaname .. ', ‘concat_and_call’: No template name was provided', 0) end
	table.remove(opts, 1)
	return ctx.frame:expandTemplate{
		title = tname,
		args = concat_params(ctx)
	}
end


-- See iface.concat_and_invoke()
library.concat_and_invoke = function(ctx)
	local opts = ctx.pipe
	local mname
	local fname
	if opts[1] ~= nil then mname = opts[1]:match'^%s*(.*%S)' end
	if mname == nil then error(ctx.luaname .. ', ‘concat_and_invoke’: No module name was provided', 0) end
	if opts[2] ~= nil then fname = opts[2]:match'^%s*(.*%S)' end
	if fname == nil then error(ctx.luaname .. ', ‘concat_and_invoke’: No function name was provided', 0) end
	table.remove(opts, 2)
	table.remove(opts, 1)
	return require('Module:' .. mname)[fname](ctx.frame:newChild{
		title = 'Module:' .. fname,
		args = concat_params(ctx)
	})
end


-- See iface.concat_and_magic()
library.concat_and_magic = function(ctx)
	local opts = ctx.pipe
	local magic
	if opts[1] ~= nil then magic = opts[1]:match'^%s*(.*%S)' end
	if magic == nil then error(ctx.luaname .. ', ‘concat_and_magic’: No parser function was provided', 0) end
	table.remove(opts, 1)
	return ctx.frame:callParserFunction(magic, concat_params(ctx))
end


-- See iface.value_of()
library.value_of = function(ctx)
	local opts = ctx.pipe
	local keystr
	if opts[1] ~= nil then keystr = opts[1]:match'^%s*(.*%S)' end
	if keystr == nil then error(ctx.luaname .. ', ‘value_of’: No parameter name was provided', 0) end
	local keynum = tonumber(keystr)
	local len = #ctx.params
	if (
		ctx.subset == -1 and keynum ~= nil and len >= keynum
	) or (
		ctx.subset == 1 and (keynum == nil or len < keynum)
	) then return (ctx.ifngiven or '') end
	local val = ctx.params[keynum or keystr]
	if val == nil then return (ctx.ifngiven or '') end
	return (ctx.header or '') .. val .. (ctx.footer or '')
end


-- See iface.list()
library.list = function(ctx)
	local kvs = ctx.pairsep or ''
	local pps = ctx.itersep or ''
	local ret = {}
	local nss = 0
	flush_params(
		ctx,
		function(key, val)
			ret[nss + 1] = pps
			ret[nss + 2] = key
			ret[nss + 3] = kvs
			ret[nss + 4] = val
			nss = nss + 4
		end
	)
	if nss > 0 then
		if nss > 4 and ctx.lastsep ~= nil then
			ret[nss - 3] = ctx.lastsep
		end
		ret[1] = ctx.header or ''
		if ctx.footer ~= nil then ret[nss + 1] = ctx.footer end
		return table.concat(ret)
	end
	return ctx.ifngiven or ''
end


-- See iface.list_values()
library.list_values = function(ctx)
	local pps = ctx.itersep or ''
	local ret = {}
	local nss = 0
	flush_params(
		ctx,
		function(key, val)
			ret[nss + 1] = pps
			ret[nss + 2] = val
			nss = nss + 2
		end
	)
	if nss > 0 then
		if nss > 2 and ctx.lastsep ~= nil then
			ret[nss - 1] = ctx.lastsep
		end
		ret[1] = ctx.header or ''
		if ctx.footer ~= nil then ret[nss + 1] = ctx.footer end
		return table.concat(ret)
	end
	return ctx.ifngiven or ''
end


-- See iface.for_each()
library.for_each = function(ctx)
	local txt = ctx.pipe[1] or ''
	local pps = ctx.itersep or ''
	local ret = {}
	local nss = 0
	flush_params(
		ctx,
		function(key, val)
			ret[nss + 1] = pps
			ret[nss + 2] = txt:gsub('%$#', key):gsub('%$@', val)
			nss = nss + 2
		end
	)
	if nss > 0 then
		if nss > 2 and ctx.lastsep ~= nil then
			ret[nss - 1] = ctx.lastsep
		end
		ret[1] = ctx.header or ''
		if ctx.footer ~= nil then ret[nss + 1] = ctx.footer end
		return table.concat(ret)
	end
	return ctx.ifngiven or ''
end


-- See iface.call_for_each()
library.call_for_each = function(ctx)
	local opts = ctx.pipe
	local tname
	if opts[1] ~= nil then tname = opts[1]:match'^%s*(.*%S)' end
	if tname == nil then error(ctx.luaname .. ', ‘call_for_each’: No template name was provided', 0) end
	local model = { title = tname, args = opts }
	local ccs = ctx.itersep or ''
	local ret = {}
	local nss = 0
	table.insert(opts, 1, true)
	flush_params(
		ctx,
		function(key, val)
			opts[1] = key
			opts[2] = val
			ret[nss + 1] = ccs
			ret[nss + 2] = ctx.frame:expandTemplate(model)
			nss = nss + 2
		end
	)
	if nss > 0 then
		if nss > 2 and ctx.lastsep ~= nil then
			ret[nss - 1] = ctx.lastsep
		end
		ret[1] = ctx.header or ''
		if ctx.footer ~= nil then ret[nss + 1] = ctx.footer end
		return table.concat(ret)
	end
	return ctx.ifngiven or ''
end


-- See iface.invoke_for_each()
library.invoke_for_each = function(ctx)
	local opts = ctx.pipe
	local mname
	local fname
	if opts[1] ~= nil then mname = opts[1]:match'^%s*(.*%S)' end
	if mname == nil then error(ctx.luaname .. ', ‘invoke_for_each’: No module name was provided', 0) end
	if opts[2] ~= nil then fname = opts[2]:match'^%s*(.*%S)' end
	if fname == nil then error(ctx.luaname .. ', ‘invoke_for_each’: No function name was provided', 0) end
	local model = { title = 'Module:' .. mname, args = opts }
	local mfunc = require(model.title)[fname]
	local ccs = ctx.itersep or ''
	local ret = {}
	local nss = 0
	flush_params(
		ctx,
		function(key, val)
			opts[1] = key
			opts[2] = val
			ret[nss + 1] = ccs
			ret[nss + 2] = mfunc(ctx.frame:newChild(model))
			nss = nss + 2
		end
	)
	if nss > 0 then
		if nss > 2 and ctx.lastsep ~= nil then
			ret[nss - 1] = ctx.lastsep
		end
		ret[1] = ctx.header or ''
		if ctx.footer ~= nil then ret[nss + 1] = ctx.footer end
		return table.concat(ret)
	end
	return ctx.ifngiven or ''
end


-- See iface.magic_for_each()
library.magic_for_each = function(ctx)
	local opts = ctx.pipe
	local magic
	if opts[1] ~= nil then magic = opts[1]:match'^%s*(.*%S)' end
	if magic == nil then error(ctx.luaname .. ', ‘magic_for_each’: No parser function was provided', 0) end
	local ccs = ctx.itersep or ''
	local ret = {}
	local nss = 0
	table.insert(opts, 1, true)
	flush_params(
		ctx,
		function(key, val)
			opts[1] = key
			opts[2] = val
			ret[nss + 1] = ccs
			ret[nss + 2] = ctx.frame:callParserFunction(magic,
				opts)
			nss = nss + 2
		end
	)
	if nss > 0 then
		if nss > 2 and ctx.lastsep ~= nil then
			ret[nss - 1] = ctx.lastsep
		end
		ret[1] = ctx.header or ''
		if ctx.footer ~= nil then ret[nss + 1] = ctx.footer end
		return table.concat(ret)
	end
	return ctx.ifngiven or ''
end


-- See iface.call_for_each_value()
library.call_for_each_value = function(ctx)
	local opts = ctx.pipe
	local tname
	if opts[1] ~= nil then tname = opts[1]:match'^%s*(.*%S)' end
	if tname == nil then error(ctx.luaname .. ', ‘call_for_each_value’: No template name was provided', 0) end
	local model = { title = tname, args = opts }
	local ccs = ctx.itersep or ''
	local ret = {}
	local nss = 0
	flush_params(
		ctx,
		function(key, val)
			opts[1] = val
			ret[nss + 1] = ccs
			ret[nss + 2] = ctx.frame:expandTemplate(model)
			nss = nss + 2
		end
	)
	if nss > 0 then
		if nss > 2 and ctx.lastsep ~= nil then
			ret[nss - 1] = ctx.lastsep
		end
		ret[1] = ctx.header or ''
		if ctx.footer ~= nil then ret[nss + 1] = ctx.footer end
		return table.concat(ret)
	end
	return ctx.ifngiven or ''
end


-- See iface.invoke_for_each_value()
library.invoke_for_each_value = function(ctx)
	local opts = ctx.pipe
	local mname
	local fname
	if opts[1] ~= nil then mname = opts[1]:match'^%s*(.*%S)' end
	if mname == nil then error(ctx.luaname .. ', ‘invoke_for_each_value’: No module name was provided', 0) end
	if opts[2] ~= nil then fname = opts[2]:match'^%s*(.*%S)' end
	if fname == nil then error(ctx.luaname .. ', ‘invoke_for_each_value’: No function name was provided', 0) end
	local model = { title = 'Module:' .. mname, args = opts }
	local mfunc = require(model.title)[fname]
	local ccs = ctx.itersep or ''
	local ret = {}
	local nss = 0
	table.remove(opts, 1)
	flush_params(
		ctx,
		function(key, val)
			opts[1] = val
			ret[nss + 1] = ccs
			ret[nss + 2] = mfunc(ctx.frame:newChild(model))
			nss = nss + 2
		end
	)
	if nss > 0 then
		if nss > 2 and ctx.lastsep ~= nil then
			ret[nss - 1] = ctx.lastsep
		end
		ret[1] = ctx.header or ''
		if ctx.footer ~= nil then ret[nss + 1] = ctx.footer end
		return table.concat(ret)
	end
	return ctx.ifngiven or ''

end


-- See iface.magic_for_each_value()
library.magic_for_each_value = function(ctx)
	local opts = ctx.pipe
	local magic
	if opts[1] ~= nil then magic = opts[1]:match'^%s*(.*%S)' end
	if magic == nil then error(ctx.luaname .. ', ‘magic_for_each_value’: No parser function was provided', 0) end
	local ccs = ctx.itersep or ''
	local ret = {}
	local nss = 0
	flush_params(
		ctx,
		function(key, val)
			opts[1] = val
			ret[nss + 1] = ccs
			ret[nss + 2] = ctx.frame:callParserFunction(magic,
				opts)
			nss = nss + 2
		end
	)
	if nss > 0 then
		if nss > 2 and ctx.lastsep ~= nil then
			ret[nss - 1] = ctx.lastsep
		end
		ret[1] = ctx.header or ''
		if ctx.footer ~= nil then ret[nss + 1] = ctx.footer end
		return table.concat(ret)
	end
	return ctx.ifngiven or ''
end



	---                                        ---
	---     PUBLIC ENVIRONMENT                 ---
	---    ________________________________    ---
	---                                        ---


-- The public table of functions
local iface = {}



	--[[ Modifiers ]]--
	------------------------------------


-- Syntax:  #invoke:params|sequential|function name
iface.sequential = function(frame)
	return context_init(frame, library.sequential, false, false)
end


-- Syntax:  #invoke:params|non-sequential|function name
iface['non-sequential'] = function(frame)
	return context_init(frame, library['non-sequential'], false, false)
end


-- Syntax:  #invoke:params|sort|function name
iface.all_sorted = function(frame)
	return context_init(frame, library.all_sorted, false, false)
end


-- Syntax:  #invoke:params|setting|directives|...|function name
iface.setting = function(frame)
	return context_init(frame, library.setting, false, false)
end


-- Syntax:  #invoke:params|squeezing|function name
iface.squeezing = function(frame)
	return context_init(frame, library.squeezing, false, false)
end


-- Syntax:  #invoke:params|cutting|left cut|right cut|function name
iface.cutting = function(frame)
	return context_init(frame, library.cutting, false, false)
end


-- Syntax:  #invoke:params|cropping|left crop|right crop|function name
iface.cropping = function(frame)
	return context_init(frame, library.cropping, false, false)
end


-- Syntax:  #invoke:params|purging|start offset|length|function name
iface.purging = function(frame)
	return context_init(frame, library.purging, false, false)
end


-- Syntax:  #invoke:params|backpurging|start offset|length|function name
iface.backpurging = function(frame)
	return context_init(frame, library.backpurging, false, false)
end


-- Syntax:  #invoke:params|reversing|function name
iface.reversing = function(frame)
	return context_init(frame, library.reversing, false, false)
end


-- Syntax:  #invoke:params|swapping|function name
--[[
iface.swapping = function(frame)
	return context_init(frame, library.swapping, false, false)
end
]]--


-- Syntax:  #invoke:params|with_name_matching|pattern 1|[plain flag 1]|[or]
--            |[pattern 2]|[plain flag 2]|[or]|[...]|[pattern N]|[plain flag
--            N]|function name
iface.with_name_matching = function(frame)
	return context_init(frame, library.with_name_matching, false, false)
end


-- Syntax:  #invoke:params|with_name_not_matching|pattern 1|[plain flag 1]
--            |[and]|[pattern 2]|[plain flag 2]|[and]|[...]|[pattern N]|[plain
--            flag N]|function name
iface.with_name_not_matching = function(frame)
	return context_init(frame, library.with_name_not_matching, false,
		false)
end


-- Syntax:  #invoke:params|with_value_matching|pattern 1|[plain flag 1]|[or]
--            |[pattern 2]|[plain flag 2]|[or]|[...]|[pattern N]|[plain flag
--            N]|function name
iface.with_value_matching = function(frame)
	return context_init(frame, library.with_value_matching, false, false)
end


-- Syntax:  #invoke:params|with_value_not_matching|pattern 1|[plain flag 1]
--            |[and]|[pattern 2]|[plain flag 2]|[and]|[...]|[pattern N]|[plain
--            flag N]|function name
iface.with_value_not_matching = function(frame)
	return context_init(frame, library.with_value_not_matching, false,
		false)
end


-- Syntax:  #invoke:params|trimming_values|function name
iface.trimming_values = function(frame)
	return context_init(frame, library.trimming_values, false, false)
end


-- Syntax:  #invoke:params|mapping_by_calling|template name|[number of
--            additional arguments]|[argument 1]|[argument 2]|[...]|[argument
--            N]|function name
iface.mapping_by_calling = function(frame)
	return context_init(frame, library.mapping_by_calling, false, false)
end


-- Syntax:  #invoke:params|mapping_by_invoking|module name|function
--            name|[number of additional arguments]|[argument 1]|[argument
--            2]|[...]|[argument N]|function name
iface.mapping_by_invoking = function(frame)
	return context_init(frame, library.mapping_by_invoking, false, false)
end


-- Syntax:  #invoke:params|mapping_blindly_by_calling|template
--            name|[number of additional arguments]|[argument 1]|[argument
--            2]|[...]|[argument N]|function name
iface.mapping_blindly_by_calling = function(frame)
	return context_init(frame, library.mapping_blindly_by_calling, false,
		false)
end


-- Syntax:  #invoke:params|mapping_blindly_by_invoking|module
--            name|function name|[number of additional arguments]|[argument
--            1]|[argument 2]|[...]|[argument N]|function name
iface.mapping_blindly_by_invoking = function(frame)
	return context_init(frame, library.mapping_blindly_by_invoking, false,
		false)
end


-- Syntax:  #invoke:params|renaming_blindly_by_calling|template
--            name|[number of additional arguments]|[argument 1]|[argument
--            2]|[...]|[argument N]|function name
iface.renaming_blindly_by_calling = function(frame)
	return context_init(frame, library.renaming_blindly_by_calling, false,
		false)
end


-- Syntax:  #invoke:params|renaming_blindly_by_invoking|module
--            name|function name|[number of additional arguments]|[argument
--            1]|[argument 2]|[...]|[argument N]|function name
iface.renaming_blindly_by_invoking = function(frame)
	return context_init(frame, library.renaming_blindly_by_invoking, false,
		false)
end




	--[[ First position only ]]--
	----------------------------------------


-- Syntax:  #invoke:params|new|function name
--[[
iface.new = function(frame)
	local ctx = context_new(frame)
	ctx.pipe = copy_or_ref_table(frame.args, false)
	ctx.params = {}
	return context_iterate(ctx, 1)
end
]]--




	--[[ Functions ]]--
	----------------------------------------


-- Syntax:  #invoke:params|count
iface.count = function(frame)
	return context_init(frame, library.count, true, true)
end


-- Syntax:  #invoke:args|concat_and_call|template name|[prepend 1]|[prepend 2]
--            |[...]|[item n]|[named item 1=value 1]|[...]|[named item n=value
--            n]|[...]
iface.concat_and_call = function(frame)
	return context_init(frame, library.concat_and_call, false, true)
end


-- Syntax:  #invoke:args|concat_and_invoke|module name|function name|[prepend
--            1]|[prepend 2]|[...]|[item n]|[named item 1=value 1]|[...]|[named
--            item n=value n]|[...]
iface.concat_and_invoke = function(frame)
	return context_init(frame, library.concat_and_invoke, false, true)
end


-- Syntax:  #invoke:args|concat_and_magic|parser function|[prepend 1]|[prepend
--            2]|[...]|[item n]|[named item 1=value 1]|[...]|[named item n=
--            value n]|[...]
iface.concat_and_magic = function(frame)
	return context_init(frame, library.concat_and_magic, false, true)
end


-- Syntax:  #invoke:params|value_of|parameter name
iface.value_of = function(frame)
	return context_init(frame, library.value_of, true, true)
end


-- Syntax:  #invoke:params|list
iface.list = function(frame)
	return context_init(frame, library.list, true, false)
end


-- Syntax:  #invoke:params|list_values
iface.list_values = function(frame)
	return context_init(frame, library.list_values, true, false)
end


-- Syntax:  #invoke:params|for_each|wikitext
iface.for_each = function(frame)
	return context_init(frame, library.for_each, true, false)
end


-- Syntax:  #invoke:params|call_for_each|template name|[append 1]|[append 2]
--            |[...]|[append n]|[named param 1=value 1]|[...]|[named param
--            n=value n]|[...]
iface.call_for_each = function(frame)
	return context_init(frame, library.call_for_each, false, false)
end


-- 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]|[...]
iface.invoke_for_each = function(frame)
	return context_init(frame, library.invoke_for_each, false, false)
end


-- Syntax:  #invoke:params|magic_for_each|parser function|[append 1]|[append 2]
--            |[...]|[append n]|[named param 1=value 1]|[...]|[named param
--            n=value n]|[...]
iface.magic_for_each = function(frame)
	return context_init(frame, library.magic_for_each, false, false)
end


-- 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]|[...]
iface.call_for_each_value = function(frame)
	return context_init(frame, library.call_for_each_value, false, false)
end


-- Syntax:  #invoke:params|invoke_for_each_value|module name|[append 1]|[append
--            2]|[...]|[append n]|[named param 1=value 1]|[...]|[named param
--            n=value n]|[...]
iface.invoke_for_each_value = function(frame)
	return context_init(frame, library.invoke_for_each_value, false, false)
end


-- 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]|[...]
iface.magic_for_each_value = function(frame)
	return context_init(frame, library.magic_for_each_value, false, false)
end




	--[[ First position only ]]--
	----------------------------------------


-- Syntax:  #invoke:params|self
iface.self = function(frame)
	return frame:getParent():getTitle()
end


return iface