[doudbassctrlr]

I have some troubles understanding how works Lua. XmlDocument is a C++ class implemented in Juce. I have some basics of C++ but I do not know how to use its constructor in Lua.
What follows:

-- @file      a File object that represents the double clicked file
[...]
myfile=XmlDocument(file)
[...]

gives me a runtime error message: “attempt to call global ‘XmlDocument’ (a nil value)”

However file really seems to be a File object as required…

[doudbassctrlr]

Great I didn’t know about Juce and its xml functions. Moreover it looks quite flexible and it should allow me to read the Musicxml files.

Just to start with, can someone help me to understand how to use Juce functions in Lua methods?

[doudbassctrlr]

Hello,
I am having a first try with a code named Slaxml.lua that is given below. I have integrated it to a method called when file is double clicked in the uiFileListBox options and get a lua runtime error saying “at line [-1]: [C] Error message: No such operator defined”.
Any idea of what is going on?

--[=====================================================================[
--v0.6 Copyright © 2013-2014 Gavin Kistner <!@phrogz.net>; MIT Licensed
--See http://github.com/Phrogz/SLAXML for details.
--]=====================================================================]
local SLAXML = {
	VERSION = "0.6",
	_call = {
		pi = function(target,content)
			print(string.format("<?%s %s?>",target,content))
		end,
		comment = function(content)
			print(string.format("<!-- %s -->",content))
		end,
		startElement = function(name,nsURI,nsPrefix)
			                 io.write("<")
			if nsPrefix then io.write(nsPrefix,":") end
			                 io.write(name)
			if nsURI    then io.write(" (ns='",nsURI,"')") end
			                 print(">")
		end,
		attribute = function(name,value,nsURI,nsPrefix)
			io.write('  ')
			if nsPrefix then io.write(nsPrefix,":") end
			                 io.write(name,'=',string.format('%q',value))
			if nsURI    then io.write(" (ns='",nsURI,"')") end
			io.write("\n")
		end,
		text = function(text)
			print(string.format("  text: %q",text))
		end,
		closeElement = function(name,nsURI,nsPrefix)
			print(string.format("</%s>",name))
		end,
	}
}

function SLAXML:parser(callbacks)
	return { _call=callbacks or self._call, parse=SLAXML.parse }
end

function SLAXML:parse(xml,options)
	if not options then options = { stripWhitespace=false } end

	-- Cache references for maximum speed
	local find, sub, gsub, char, push, pop = string.find, string.sub, string.gsub, string.char, table.insert, table.remove
	local first, last, match1, match2, match3, pos2, nsURI
	local unpack = unpack or table.unpack
	local pos = 1
	local state = "text"
	local textStart = 1
	local currentElement={}
	local currentAttributes={}
	local currentAttributeCt -- manually track length since the table is re-used
	local nsStack = {}

	local entityMap  = { ["lt"]="<", ["gt"]=">", ["amp"]="&", ["quot"]='"', ["apos"]="'" }
	local entitySwap = function(orig,n,s) return entityMap or n=="#" and char(s) or orig end
	local function unescape(str) return gsub( str, '(&(#?)([%d%a]+);)', entitySwap ) end
	local anyElement = false

	local function finishText()
		if first>textStart and self._call.text then
			local text = sub(xml,textStart,first-1)
			if options.stripWhitespace then
				text = gsub(text,'^%s+','')
				text = gsub(text,'%s+$','')
				if #text==0 then text=nil end
			end
			if text then self._call.text(unescape(text)) end
		end
	end

	local function findPI()
		first, last, match1, match2 = find( xml, '^<%?([:%a_][:%w_.-]*) ?(.-)%?>', pos )
		if first then
			finishText()
			if self._call.pi then self._call.pi(match1,match2) end
			pos = last+1
			textStart = pos
			return true
		end
	end

	local function findComment()
		first, last, match1 = find( xml, '^<!%-%-(.-)%-%->', pos )
		if first then
			finishText()
			if self._call.comment then self._call.comment(match1) end
			pos = last+1
			textStart = pos
			return true
		end
	end

	local function nsForPrefix(prefix)
		if prefix=='xml' then return 'http://www.w3.org/XML/1998/namespace' end -- http://www.w3.org/TR/xml-names/#ns-decl
		for i=#nsStack,1,-1 do if nsStack[prefix] then return nsStack[prefix] end end
		error(("Cannot find namespace for prefix %s"):format(prefix))
	end

	local function startElement()
		anyElement = true
		first, last, match1 = find( xml, '^<([%a_][%w_.-]*)', pos )
		if first then
			currentElement[2] = nil -- reset the nsURI, since this table is re-used
			currentElement[3] = nil -- reset the nsPrefix, since this table is re-used
			finishText()
			pos = last+1
			first,last,match2 = find(xml, '^:([%a_][%w_.-]*)', pos )
			if first then
				currentElement[1] = match2
				currentElement[3] = match1 -- Save the prefix for later resolution
				match1 = match2
				pos = last+1
			else
				currentElement[1] = match1
				for i=#nsStack,1,-1 do if nsStack['!'] then currentElement[2] = nsStack['!']; break end end
			end
			currentAttributeCt = 0
			push(nsStack,{})
			return true
		end
	end

	local function findAttribute()
		first, last, match1 = find( xml, '^%s+([:%a_][:%w_.-]*)%s*=%s*', pos )
		if first then
			pos2 = last+1
			first, last, match2 = find( xml, '^"([^<"]*)"', pos2 ) -- FIXME: disallow non-entity ampersands
			if first then
				pos = last+1
				match2 = unescape(match2)
			else
				first, last, match2 = find( xml, "^'([^<']*)'", pos2 ) -- FIXME: disallow non-entity ampersands
				if first then
					pos = last+1
					match2 = unescape(match2)
				end
			end
		end
		if match1 and match2 then
			local currentAttribute = {match1,match2}
			local prefix,name = string.match(match1,'^([^:]+):([^:]+)$')
			if prefix then
				if prefix=='xmlns' then
					nsStack[#nsStack][name] = match2
				else
					currentAttribute[1] = name
					currentAttribute[4] = prefix
				end
			else
				if match1=='xmlns' then
					nsStack[#nsStack]['!'] = match2
					currentElement[2]      = match2
				end
			end
			currentAttributeCt = currentAttributeCt + 1
			currentAttributes[currentAttributeCt] = currentAttribute
			return true
		end
	end

	local function findCDATA()
		first, last, match1 = find( xml, '^<!%[CDATA%[(.-)%]%]>', pos )
		if first then
			finishText()
			if self._call.text then self._call.text(match1) end
			pos = last+1
			textStart = pos
			return true
		end
	end

	local function closeElement()
		first, last, match1 = find( xml, '^%s*(/?)>', pos )
		if first then
			state = "text"
			pos = last+1
			textStart = pos

			-- Resolve namespace prefixes AFTER all new/redefined prefixes have been parsed
			if currentElement[3] then currentElement[2] = nsForPrefix(currentElement[3])    end
			if self._call.startElement then self._call.startElement(unpack(currentElement)) end
			if self._call.attribute then
				for i=1,currentAttributeCt do
					if currentAttributes[4] then currentAttributes[3] = nsForPrefix(currentAttributes[4]) end
					self._call.attribute(unpack(currentAttributes))
				end
			end

			if match1=="/" then
				pop(nsStack)
				if self._call.closeElement then self._call.closeElement(unpack(currentElement)) end
			end
			return true
		end
	end

	local function findElementClose()
		first, last, match1, match2 = find( xml, '^</([%a_][%w_.-]*)%s*>', pos )
		if first then
			nsURI = nil
			for i=#nsStack,1,-1 do if nsStack['!'] then nsURI = nsStack['!']; break end end
		else
			first, last, match2, match1 = find( xml, '^</([%a_][%w_.-]*):([%a_][%w_.-]*)%s*>', pos )
			if first then nsURI = nsForPrefix(match2) end
		end
		if first then
			finishText()
			if self._call.closeElement then self._call.closeElement(match1,nsURI) end
			pos = last+1
			textStart = pos
			pop(nsStack)
			return true
		end
	end

	while pos<#xml do
		if state=="text" then
			if not (findPI() or findComment() or findCDATA() or findElementClose()) then		
				if startElement() then
					state = "attributes"
				else
					first, last = find( xml, '^[^<]+', pos )
					pos = (first and last or pos) + 1
				end
			end
		elseif state=="attributes" then
			if not findAttribute() then
				if not closeElement() then
					error("Was in an element and couldn't find attributes or the close.")
				end
			end
		end
	end

	if not anyElement then error("Parsing did not discover any elements") end
	if #nsStack > 0 then error("Parsing ended with unclosed elements") end
end

--return SLAXML
--
-- Called when a file is double clicked
--
-- @modulator the modulator the event occured on
-- @file      a File object that represents the double clicked file
--
MusixmlReader = function(modulator, file)
SLAXML:parse(file)
end

[doudbassctrlr]

I agree that MidiThru do not concern midi messages delivered by the panel but it was the options you previously adviced me to check…
The “output to plugin host” however should do the job as far as I understand it and it does when Lua script is not involved, that is when I want to use the Midi messages pre-build options in the uibutton side panel.
Now I thought that sendMidiMessageNow(..) from Lua would deliver midi messages the same way (i.e. to the plugin output) and was not linked to any output device port…

[doudbassctrlr]

Thanks a lot for your help. I now get the programmed midi notes. I am getting closer now to a solution, however I am getting confused about some routing points. More specificaly: it seems that sendMidiMessageNow() can only send midi to a Midi output device while Midi options of the uicomponent can lead to the plugin output… Am I wrong?

Now, here is how it works for me:
– To get Lua method programmed midi messages working I had to select an output device and I had none, so I used a virtual midi cable
– The plugin output won’t deliver Midi messages from the Lua Method and I can uncheck all the MidiThru options and output to plugin. And it still works as far as the output virtual cable is correctly plugged in.

So strange… I do not understand this routing issue…
Any idea?

[doudbassctrlr]

I have tried the lua code with a new slider in a new panel using the indicated options but nothing new.
What I am now sure of is that the Lua code is well read since a console test can well be printed when modulator value is changed. However what I cannot figure out is why sendMidiMessageNow(…) function do not produce any output.
Is there another function that would lead to a midi message output?

[doudbassctrlr]

Finaly one reassuring point. I am not going completly wrong with the lua code and it should lead to delivering midi messages.
– Which version of Ctrlr are you using?
– Is it working with the vst version?

I tried to use another DAW as plugin host (Reaper) and build a new vst with all the indicated options for delivering midi messages checked. I inserted only one uibutton and attributed the Lua method to be sent when modulator value is changed. It does not work either…
Any new idea?

[doudbassctrlr]

I have just tried this combinaison of options but nothing new.
It seems to me that “Output to plugin host” should be sufficient as, for the moment, I am just trying to send Midi messages through the Lua method as I toggle the uibutton…

[doudbassctrlr]

I have never used Lua before but I am a bit familiar with C++.
I think I will be able to go further in the vst construction if I can fix the midi sending problems.
Do anybody know what is going wrong with the Lua method given in the above replies?
Do you have any simple test for me to check if sending midi message through Lua is working correctly?
Thanks a lot

[doudbassctrlr]

It seems that everything is correctly plugged in, I am able to switch on/off the “moot” vst. Ctrlr midi output is also received in a midi monitor in Bidule that attests for the Note-On midi sending when I use the pre-build options for sending midi messages. But the lua method called at modulator values changes do not produce any signal.

I tried the following:

myMethod=function(mod, value)
p=CtrlrMidiMessage({0x80,0x3C,0x10})
m={0xF0; 0x18, 0x21, 0x01, 0x55, 0x16, 0xF7}
panel:sendMidiMessageNow(CtrlrMidiMessage(m))
panel:sendMidiMessageNow(p)
end

I hope both are good midi messages (the second one m is taken from working code in the forum). No new output at modulator values changes.

Here is the version of Ctrlr I use:
Revision = ac6a31852a8e26ddbf6a7133f87f1fd6dac8a6c4, Build date = Thu 04/24/2014, Branch = Nightly, Juce = 3.0.5, Boost = 1.52.0, Lua = 5.1.4,

I also noticed two disturbing features, that might help:
– midi messages go through when the midi device is plugged in the midi input of the vst although the only option in the midi menu that is checked is the “output to plugin host” option
– Even with the working pre-build version for sending midi notes (i.e. using uibutton Midi tab), I get nothing in the ctrlr integrated midi monitor for output, only input monitor displays something

[doudbassctrlr]

I had several attempts to solve my program sending midi notes problem.
Finally, as I cannot see any midi output when executing
panel:sendMidiMessageNow(midimessage)
as the method used when modulator value is changed, I was wondering if the output is the same as the midi message option for uibuttons.
More precisely I use Ctrlr as a vst in Bidule with no midi input or output devices but toggling each button through a learn functionnality. Non-method midi notes (the one I can access in the ui options) are then sent without any troubles to other vst. But when the method is called I get nothing new…
Are the outputs of these two different ways to proceed not the same?

• This reply was modified 9 years, 11 months ago by doudbassctrlr.

[doudbassctrlr]

I have tried using a true Note-On message but it does not solve, even worth:
I get back the “Callback error” message.

I am not used to manipulating midi, and english either (sorry for that), but I thought I should in any case see something in the output. Does the first byte include in itself some constraints on the structure that follows?

[doudbassctrlr]

Hello,

# I have tried to put in “called when modulator value is changed” a method with the following “forum-inspired” code:

messageToSend=MemoryBlock({0x90,0x3C,0x00,0x40})
message = CtrlrMidiMessage({0x90,0x3C,0x00,0x40})
panel:sendMidiMessageNow(message)

I have saved it and compiled but nothing happens, I have no output…

# I don’t understand either how I can call some specific modulator values for tests. How does it work?
# Is it possible also to define say a live configuration using uicombos and
according to the selected name send the appropriate set of midi notes?

Thanks a lot for consideration
Doud

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