Example usage of revx2.lua to generate Faust file containing the loop samples directly

rx2tofaust.lua

-- wget https://github.com/rxi/json.lua/raw/master/json.lua
local revx2 = require("revx2")
local inspect = require 'inspect'
local json = require "json"
local wav = require'luawav'

local path = "/path/to/json.json"

local json_file = io.open(path)
local loop = json.decode(json_file:read("*all"))
print(inspect(loop))

local base_faust = [[
import("stdfaust.lib");

]]

function addEnvironnement(str, name, content)
	local env = name .. " = environment {\n" .. content .. "};\n"
	return str .. env
end

function addVariable(str, name, value)
	local var = name .. " = " .. value .. ";\n"
	return str .. var
end

function addProcess(str, content)
	local proc = "\nprocess = " .. content .. ";\n"
	return str .. proc
end

local loop_vars = ""
loop_vars = addVariable(loop_vars, "	slices", loop.effective_slices)
loop_vars = addVariable(loop_vars, "	tempo", loop.tempo)

local start_samples = "waveform{ "
local length_samples = "waveform{ "
for slice, tbl in ipairs(loop.slices_list) do
	start_samples = start_samples .. tbl.start .. ", "
	length_samples = length_samples .. tbl.length .. ", "
	print(slice, tbl.start, tbl.length, " -> ", tbl.start + tbl.length)
end
start_samples = string.sub(start_samples, 1, -3) .. " }"
length_samples = string.sub(length_samples, 1, -3) .. " }"
loop_vars = addVariable(loop_vars, "	start", start_samples)
loop_vars = addVariable(loop_vars, "	length", length_samples)

local meta_and_samples = wav.drwav_open_and_read_pcm_frames_f32(loop.wav_file)
print(inspect(meta_and_samples, {depth=1}))
print(#meta_and_samples.samples / meta_and_samples.channels, (#meta_and_samples.samples / meta_and_samples.channels) / meta_and_samples.sampleRate)
local loop_samples = "waveform{ " .. table.concat(meta_and_samples.samples, ", ") .. "}"
loop_vars = addVariable(loop_vars, "	loop_samples", loop_samples)

local loop_file = base_faust
loop_file = addEnvironnement(loop_file, "loop_1", loop_vars)
-- loop_file = addProcess(loop_file, "0.0")

local lib_path = string.sub(path, 1, -5) .. "lib"
local lib_file = io.open(lib_path, 'w')
lib_file:write(loop_file)
lib_file:close()

print("Saved to " .. lib_path)

-- os.execute("mg " .. lib_path)