Module:ED intro

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This module should not be invoked directly; use its corresponding template instead: Template:ED intro.

This module automatically fills in an introduction for an equal-step tuning. It has presets for the most common equivalences (octave, tritave, and perfect fifth) and also supports arbitrary equivalences and arithmetic pitch sequences such as 88cET.

Introspection summary for Module:ED intro 
Functions provided (9)
Line Function Params
20 edo_intro (ed)
47 edt_intro (ed)
74 edf_intro (ed)
101 edh_intro (ed, harmonic)
131 edr_intro (ed, ratio)
159 edc_intro (ed, cents, constant_symbol)
164 parse (unparsed)
201 _ed_intro (main) (ed)
224 ed_intro (invokable) (frame)
Lua modules required (3)
Variable Module Functions used
ord Module:Ordinal _ordinal
rat Module:Rational new
cents
as_ratio
eq
is_harmonic
utils Module:Utils _round

No function descriptions were provided. The Lua code may have further information.


local ord = require('Module:Ordinal')
local utils = require('Module:Utils')
local rat = require('Module:Rational')
local p = {}

-- TODO: Add support for the following
-- - edc - equal divisions of a non-integer constant or cent value

-- Notes:
-- - Edo and edt are technically edh's, and edf an edr; these are their own
--   types because their intros have specific wording.
-- - Edh is a special case of edr, where the ratio is h/1.
-- - Under harmonotonic tuning, edc and edr are also called ASp and APSp
--   (ambitonal sequence and arithmetic pitch sequence, respectively). These
--   were formerly called equal-step tunings but were reclassified as 1ed.
-- - Equal divisions of irrational constants (such as pi and e) are not very
--   common, but count as equal divisions of arbitrary cent values.

-- Separate function for edo intro
function p.edo_intro(ed)
	local ed = ed or 12
	
	-- Exactly or about? Round to 3 DPs
	local edstep_size = 1200 / ed
	local edstep_size_rounded = utils._round(edstep_size, 3)
	local is_exact = edstep_size - edstep_size_rounded == 0
	
	local ordinal = ord._ordinal(ed)
	
	local intro_text = ""
	if ed == 1 then
		intro_text = "'''''k'' equal divisions of the octave''' (abbreviated '''''k''edo''' or '''''k''ed2'''), also called '''''k''-tone equal temperament''' ('''''k''tet''') or '''''k'' equal temperament''' ('''''k''et''') when viewed under a [[regular temperament]] perspective, is the [[tuning system]] where adjacent pitches are one interval of 2/1 (one [[octave]]) apart, or exactly/about ''s'' [[¢]]."	
	else
		intro_text = "'''''k'' equal divisions of the octave''' (abbreviated '''''k''edo''' or '''''k''ed2'''), also called '''''k''-tone equal temperament''' ('''''k''tet''') or '''''k'' equal temperament''' ('''''k''et''') when viewed under a [[regular temperament]] perspective, is the [[tuning system]] that divides the [[octave]] into ''k'' [[equal]] parts of exactly/about ''s'' [[¢]] each. Each step represents a [[frequency ratio]] of 2<sup>1/''k''</sup>, or the ''kth'' root of 2."	
	end

	-- Replace certain strings with the intended final versions
	intro_text = string.gsub(intro_text, "''k''", ed)
	intro_text = string.gsub(intro_text, "exactly/about", (is_exact and "exactly" or "about"))
	intro_text = string.gsub(intro_text, "''s''", string.format("%.3f", edstep_size))
	intro_text = string.gsub(intro_text, "''kth''", ord._ordinal(ed))
	
	return intro_text
end

-- Separate function for edt intro
function p.edt_intro(ed)
	local ed = ed or 13
	
	-- Exactly or about? Round to 3 DPs
	local edstep_size = math.log(3) * 1200 / math.log(2) / ed
	local edstep_size_rounded = utils._round(edstep_size, 3)
	local is_exact = edstep_size - edstep_size_rounded == 0
	
	local ordinal = ord._ordinal(ed)
	
	local intro_text = ""
	if ed == 1 then
		intro_text = "'''''k'' equal divisions of the tritave''', '''perfect twelfth''', or '''3rd harmonic''' (abbreviated '''''k''edt''' or '''''k''ed3'''), is the [[nonoctave]] [[tuning system]] where adjacent pitches are one interval of 3/1 (one [[tritave]]) apart, or exactly/about ''s'' [[¢]]."	
	else
		intro_text = "'''''k'' equal divisions of the tritave''', '''perfect twelfth''', or '''3rd harmonic''' (abbreviated '''''k''edt''' or '''''k''ed3'''), is the [[nonoctave]] [[tuning system]] that divides the interval of [[3/1]] into ''k'' [[equal]] parts of exactly/about ''s'' [[¢]] each. Each step represents a [[frequency ratio]] of 3<sup>1/''k''</sup>, or the ''kth'' root of 3."	
	end

	-- Replace certain strings with the intended final versions
	intro_text = string.gsub(intro_text, "''k''", ed)
	intro_text = string.gsub(intro_text, "exactly/about", (is_exact and "exactly" or "about"))
	intro_text = string.gsub(intro_text, "''s''", string.format("%.3f", edstep_size))
	intro_text = string.gsub(intro_text, "''kth''", ord._ordinal(ed))
	
	return intro_text
end

-- Separate function for edf intro
function p.edf_intro(ed)
	local ed = ed or 7
	
	-- Exactly or about? Round to 3 DPs
	local edstep_size = math.log(3/2) * 1200 / math.log(2) / ed
	local edstep_size_rounded = utils._round(edstep_size, 3)
	local is_exact = edstep_size - edstep_size_rounded == 0
	
	local ordinal = ord._ordinal(ed)
	
	local intro_text = ""
	if ed == 1 then
		intro_text = "'''''k'' equal divisions of the perfect fifth''' (abbreviated '''''k''edf''' or '''''k''ed3/2'''), is the [[nonoctave]] [[tuning system]] where adjacent pitches are one interval of 3/2 (one [[tritave]]) apart, or exactly/about ''s'' [[¢]]."	
	else
		intro_text = "'''''k'' equal divisions of the perfect fifth''' (abbreviated '''''k''edf''' or '''''k''ed3/2'''), is the [[nonoctave]] [[tuning system]] that divides the interval of [[3/2]] into ''k'' [[equal]] parts of exactly/about ''s'' [[¢]] each. Each step represents a [[frequency ratio]] of (3/2)<sup>1/''k''</sup>, or the ''kth'' root of 3/2."	
	end

	-- Replace certain strings with the intended final versions
	intro_text = string.gsub(intro_text, "''k''", ed)
	intro_text = string.gsub(intro_text, "exactly/about", (is_exact and "exactly" or "about"))
	intro_text = string.gsub(intro_text, "''s''", string.format("%.3f", edstep_size))
	intro_text = string.gsub(intro_text, "''kth''", ord._ordinal(ed))
	
	return intro_text
end

-- Separate function for edh intro (arbitrary harmonic)
function p.edh_intro(ed, harmonic)
	local ed = ed or 12
	local harmonic = harmonic or 4
	
	-- Exactly or about? Round to 3 DPs
	local edstep_size = math.log(harmonic) * 1200 / math.log(2) / ed
	local edstep_size_rounded = utils._round(edstep_size, 3)
	local is_exact = edstep_size - edstep_size_rounded == 0
	
	local ordinal = ord._ordinal(ed)
	
	local intro_text = ""
	if ed == 1 then
		intro_text = "'''''k'' equal divisions of the hth harmonic''' (abbreviated '''''k''ed''h'''''), is the [[nonoctave]] [[tuning system]] where adjacent pitches are one interval of [[''h''/1]] apart, or exactly/about ''s'' [[¢]]."	
	else
		intro_text = "'''''k'' equal divisions of the hth harmonic''' (abbreviated '''''k''ed''h'''''), is the [[nonoctave]] [[tuning system]] that divides the interval of [[''h''/1]] into ''k'' [[equal]] parts of exactly/about ''s'' [[¢]] each. Each step represents a [[frequency ratio]] of ''h''<sup>1/''k''</sup>, or the ''kth'' root of ''h''."	
	end

	-- Replace certain strings with the intended final versions
	intro_text = string.gsub(intro_text, "''k''", ed)
	intro_text = string.gsub(intro_text, "exactly/about", (is_exact and "exactly" or "about"))
	intro_text = string.gsub(intro_text, "''s''", string.format("%.3f", edstep_size))
	intro_text = string.gsub(intro_text, "''kth''", ord._ordinal(ed))
	intro_text = string.gsub(intro_text, "hth", ord._ordinal(harmonic))
	intro_text = string.gsub(intro_text, "''h''", harmonic)
	
	return intro_text
end

-- Separate function for edr intro (arbitrary ratio)
function p.edr_intro(ed, ratio)
	local ed = ed or 12
	local ratio = ratio or rat.new(9,4)
	
	-- Exactly or about? Round to 3 DPs
	local edstep_size = rat.cents(ratio) / ed
	local edstep_size_rounded = utils._round(edstep_size, 3)
	local is_exact = edstep_size - edstep_size_rounded == 0
	
	local ordinal = ord._ordinal(ed)
	
	local intro_text = ""
	if ed == 1 then
		intro_text = "'''''k'' equal divisions of ''p/q''''' (abbreviated '''''k''ed''p/q''''') is the [[nonoctave]] [[tuning system]] where adjacent pitches are one interval of [[p/q]] apart, or exactly/about ''s'' [[¢]]."	
	else
		intro_text = "'''''k'' equal divisions of ''p/q''''' (abbreviated '''''k''ed''p/q''''') is the [[nonoctave]] [[tuning system]] that divides the interval of [[''p/q'']] into ''k'' [[equal]] parts of exactly/about ''s'' [[¢]] each. Each step represents a [[frequency ratio]] of ''p/q''<sup>1/''k''</sup>, or the ''kth'' root of ''p/q''."	
	end

	-- Replace certain strings with the intended final versions
	intro_text = string.gsub(intro_text, "''k''", ed)
	intro_text = string.gsub(intro_text, "exactly/about", (is_exact and "exactly" or "about"))
	intro_text = string.gsub(intro_text, "''s''", string.format("%.3f", edstep_size))
	intro_text = string.gsub(intro_text, "''kth''", ord._ordinal(ed))
	intro_text = string.gsub(intro_text, "''p/q''", rat.as_ratio(ratio))
	
	return intro_text
end

function p.edc_intro(ed, cents, constant_symbol)
	return "Equal divisions of an arbitrary cent value currently not supported."
end

-- Parse function
function p.parse(unparsed)
	local unparsed = unparsed or "12"
	
	-- If the unparsed ed is only a numeric value, default to edo
	if tonumber(unparsed) ~= nil then
		unparsed = unparsed .. "edo"
	end
	
	-- Parse the step count, the suffix, and the equave
	local steps, equave = unparsed:match('^(%d+)[Ee][Dd](.+)$')
	
	local parsed_equave
	if equave == "o" or equave == "O" or equave == "2" or equave == "2/1" then
		-- Equave is octave
		parsed_equave = 2
	elseif equave == "t" or equave == "T" or equave == "3" or equave == "3/1" then
		-- Equave is tritave/twelfth
		parsed_equave = 3
	elseif equave == "f" or equave == "F" or equave == "3/2" then
		-- Equave is fifth
		parsed_equave = rat.new(3,2)
	elseif string.match(equave, '^%d+$') ~= nil then
		-- Equave is arbitrary harmonic (not 2/1 or 3/1)
		parsed_equave = tonumber(equave)
	elseif string.match(equave, '^%d+/%d+$') ~= nil then
		-- Equave is arbitrary ratio (not 3/2)
		local num, den = equave:match('^(%d+)/(%d+)$')
		parsed_equave = rat.new(tonumber(num), tonumber(den))
	else
		-- Equave is unsupported
		parsed_equave = 0
	end
	
	return steps, parsed_equave
end

-- Primary function
function p._ed_intro(ed)
	local ed = ed or "12ed4/3"
	
	local parsed_ed, parsed_equave = p.parse(ed)
	
	if rat.eq(0, parsed_equave) then
		return "Equave not supported."
	elseif rat.eq(2, parsed_equave) then
		return p.edo_intro(parsed_ed)
	elseif rat.eq(3, parsed_equave) then
		return p.edt_intro(parsed_ed)
	elseif rat.eq(rat.new(3,2), parsed_equave) then
		return p.edf_intro(parsed_ed)
	elseif rat.is_harmonic(parsed_equave) then
		return p.edh_intro(parsed_ed, parsed_equave)
	elseif not rat.is_harmonic(parsed_equave) then
		return p.edr_intro(parsed_ed, parsed_equave)
	else
		return "Invalid input."
	end
end

-- Wrapper function; for use with a template
function p.ed_intro(frame)
	local ed = frame.args['ED']

	return p._ed_intro(ed)
end

return p