modelverse/bootstrap/core_algorithm.alc

include "modelling.alh"
include "library.alh"
include "primitives.alh"
include "constructors.alh"
include "object_operations.alh"
include "mini_modify.alh"
include "model_management.alh"
include "ramify.alh"
include "conformance_scd.alh"
include "transform.alh"
include "metamodels.alh"
include "utils.alh"
include "conformance_finding.alh"
include "typing.alh"
include "compiler.alh"
include "random.alh"
include "io.alh"

String core_model_location = "models/core"

Element core = ?
String current_user_id
Element caches
Element pm_tasks = ?

String function get_foldername(name : String):
	Element result
	result = string_split(name, "/")
	list_pop_final(result)

	if (list_len(result) == 0):
		return ""!

	// 'result' now contains a list of entries which we have to join with the seperator
	String str
	str = list_pop_final(result)

	while (list_len(result) > 0):
		str = cast_string(list_pop_final(result)) + "/" + str

	return str!

String function get_filename(name : String):
	return list_pop_final(string_split(name, "/"))!

String function full_name(model_id : String):
	if (dict_in(core["model"], model_id)):
		return read_attribute(core, model_id, "name")!
	else:
		return read_root()!

Void function initialize_core():
	// TODO make this more flexible by putting it in the bootstrap in a similar way as other models
	return !

Boolean function is_typed_by(model_id : String, metamodel_id : String):
	return (set_len(get_instanceOf_links(model_id, metamodel_id)) > 0)!

Element function get_instanceOf_links(model_id : String, metamodel_id : String):
	Element result
	Element options
	String elem

	result = set_create()
	options = allOutgoingAssociationInstances(core, model_id, "instanceOf")
	while (set_len(options) > 0):
		elem = set_pop(options)
		if (value_eq(readAssociationDestination(core, elem), metamodel_id)):
			set_add(result, elem)

	return result!

String function get_instanceOf_link(model_id : String, metamodel_id : String):
	Element all_links
	String choice

	all_links = get_instanceOf_links(model_id, metamodel_id)

	if (set_len(all_links) > 1):
		log("WARNING: multiple instanceOf relations were detected for this model; picking one at random!")
	elif (set_len(all_links) == 0):
		//log("No types found!")
		//log("Source model: " + cast_value(read_attribute(core, model_id, "name")))
		//log("Target meta-model: " + cast_value(read_attribute(core, metamodel_id, "name")))
		return read_root()!
	
	choice = set_pop(all_links)

	return choice!

Element function get_full_model(model_id : String, metamodel_id : String):
	// TODO we are restricted to using formalisms/SimpleClassDiagrams as M3 level, through this code!
	Element m
	Element all_links
	String choice

	choice = get_instanceOf_link(model_id, metamodel_id)

	m = dict_create()
	dict_add(m, "model", import_node(read_attribute(core, model_id, "location")))

	// TODO for now this is restricted to the fixed semantics
	// dict_add(m, "semantics", anAssociationDestination(core, choice, "semantics"))
	//dict_add(m, "semantics", get_entry_id("models/conformance_mv"))

	if (metamodel_id == model_id):
		// Found the meta-circular level, so we can stop!
		dict_add(m, "metamodel", m)
	else:
		Element mm
		mm = get_full_model(metamodel_id, get_entry_id("formalisms/SimpleClassDiagrams"))
		if (element_eq(mm, read_root())):
			log("Error finding type mapping...")
			return read_root()!
		else:
			dict_add(m, "metamodel", mm)

	if (element_neq(choice, read_root())):
		Element types
		types = allAssociationDestinations(core, choice, "typing")
		if (set_len(types) == 1):
			// Add the preferred original type mapping
			set_type_mapping(m, import_node(read_attribute(core, set_pop(types), "location")))
		else:
			// Start from scratch
			new_type_mapping(m)
	else:
		// Start from scratch
		new_type_mapping(m)
	
	if (find_type_mapping(m)):
		// TODO store the found type model somewhere
		return m!
	else:
		log("No type mapping could be deduced!")
		log("Error for " + cast_value(read_attribute(core, model_id, "name")))
		log(" and type " + cast_value(read_attribute(core, metamodel_id, "name")))
		return read_root()!

Integer function get_relation_to_model(user_id : String, model_id : String):
	if (set_in(allAssociationDestinations(core, model_id, "owner"), user_id)):
		// We are the owner
		return 0!
	else:
		String group_id
		group_id = anAssociationDestination(core, model_id, "group")
		if (set_in(allAssociationDestinations(core, user_id, "belongsTo"), group_id)):
			// We are in the owning group
			return 1!
		else:
			// We are not related whatsoever
			return 2!

Boolean function is_admin(user_id : String):
	if (read_attribute(core, user_id, "admin")):
		return True!
	else:
		return False!
	
Boolean function allow_execute(user_id : String, model_id : String):
	return allow_read(user_id, model_id)!

Boolean function allow_read(user_id : String, model_id : String):
	if (is_admin(user_id)):
		// Is admin, so always allow
		return True!
	else:
		// Check permissions
		String permission
		permission = string_get(read_attribute(core, model_id, "permissions"), get_relation_to_model(user_id, model_id))
		if (bool_or(permission == "1", permission == "2")):
			return True!
		else:
			return False!

Boolean function allow_write(user_id : String, model_id : String):
	if (is_admin(user_id)):
		// Is admin, so always allow
		return True!
	else:
		// Check permissions
		String permission
		permission = string_get(read_attribute(core, model_id, "permissions"), get_relation_to_model(user_id, model_id))
		if (permission == "2"):
			return True!
		else:
			return False!

Boolean function allow_change_metadata(user_id : String, model_id : String):
	if (is_admin(user_id)):
		// Is admin, so always allow
		return True!
	else:
		if (get_relation_to_model(user_id, model_id) == 0):
			// Only owner can chmod
			return True!
		else:
			return False!

Boolean function allow_group_modify(user_id : String, group_id : String):
	if (is_admin(user_id)):
		// Is admin, so always allow
		return True!
	else:
		if (set_in(allAssociationDestinations(core, group_id, "owner"), user_id)):
			// We are an owner
			return True!
		else:
			return False!

Boolean function check_login(user_id : String):
	String password
	String stored_password

	stored_password = read_attribute(core, user_id, "password")

	output("Password for existing user?")
	password = hash(input())

	return password == stored_password!

String function get_entry_id(name : String):
	Element hierarchy_split
	String current
	Integer i
	Element elems
	String elem
	Boolean found
	String folder_name

	if (name == ""):
		return caches["root"]!

	if (string_get(name, string_len(name) - 1) == "/"):
		name = string_substr(name, 0, string_len(name) - 1)

	log("Got location: " + name)
	name = string_replace(name, "~", "users/" + cast_string(read_attribute(core, current_user_id, "name")))
	log("Rewrote: " + name)

	if (dict_in(caches["models"], name)):
		if (dict_in(core, caches["models"])):
			if (full_name(caches["models"][name]) == name):
				return caches["models"][name]!

	folder_name = get_foldername(name)
	current = get_entry_id(folder_name)

	if (current == ""):
		return ""!

	elems = allAssociationDestinations(core, current, "contains")
	while (set_len(elems) > 0):
		elem = set_pop(elems)
		dict_overwrite(caches["models"], read_attribute(core, elem, "name"), elem)
		if (value_eq(name, read_attribute(core, elem, "name"))):
			return elem!

	return ""!

String function get_service_id(name : String):
	core = import_node(core_model_location)
	Element services
	String service

	services = allInstances(core, "Service")

	while (set_len(services) > 0):
		service = set_pop(services)
		if (value_eq(read_attribute(core, service, "name"), name)):
			return service!
	
	return ""!

String function get_user_id(name : String):
	Element users
	String user

	users = allInstances(core, "User")

	while (set_len(users) > 0):
		user = set_pop(users)
		if (value_eq(read_attribute(core, user, "name"), name)):
			return user!
	
	return ""!

String function get_group_id(name : String):
	Element groups
	String group

	groups = allInstances(core, "Group")
	while (set_len(groups) > 0):
		group = set_pop(groups)
		if (value_eq(read_attribute(core, group, "name"), name)):
			return group!
	
	return ""!

String function create_folders(user_id : String, folder_name : String):
	Element hierarchy
	Integer i
	String prev
	String elem
	String new_entry
	String cummul

	if (get_entry_id(folder_name) != ""):
		// Folders already exist, so don't iterate
		return get_entry_id(folder_name)!

	i = 0
	hierarchy = string_split(folder_name, "/")
	prev = get_entry_id("")
	cummul = ""

	// Go through folders first
	while (i < list_len(hierarchy)):
		elem = list_read(hierarchy, i)
		if (cummul == ""):
			cummul = elem
		else:
			cummul = string_join(cummul + "/", elem)

		if (get_entry_id(cummul) == ""):
			if (allow_write(current_user_id, prev)):
				// Element does not exist yet!
				new_entry = instantiate_node(core, "Folder", "")
				instantiate_attribute(core, new_entry, "name", cummul)
				instantiate_attribute(core, new_entry, "permissions", "200")
				instantiate_link(core, "contains", "", prev, new_entry)
				instantiate_link(core, "group", "", new_entry, get_group_id("nobody"))
				instantiate_link(core, "owner", "", new_entry, user_id)
			else:
				return read_root()!

		prev = get_entry_id(cummul)
		i = i + 1

	return prev!

String function store_entry(model_id : String, full_name : String, user_id : String):
	String prev

	if (get_entry_id(full_name) != ""):
		// Delete any old models
		model_delete(get_entry_id(full_name))

	prev = create_folders(user_id, get_foldername(full_name))
	instantiate_link(core, "contains", "", prev, model_id)
	return full_name!

String function export_typing(model : Element, name : String):
	String result
	result = instantiate_node(core, "TypeMapping", "")

	// Create type mapping model
	String location
	location = "type mappings/" + cast_id(get_type_mapping(model))
	export_node(location, get_type_mapping(model))
	name = location

	String instance_of
	name = store_entry(result, name, current_user_id)
	instantiate_attribute(core, result, "name", name)
	instantiate_attribute(core, result, "location", location)
	instantiate_attribute(core, result, "permissions", "200")
	instantiate_link(core, "owner", "", result, current_user_id)
	instantiate_link(core, "group", "", result, get_group_id("nobody"))
	instance_of = instantiate_link(core, "instanceOf", "", result, get_entry_id("formalisms/TypeMapping"))
	//instantiate_link(core, "semantics", "", instance_of, get_entry_id("models/conformance_mv"))

	return result!

Void function model_create(model : Element, name : String, type_id : String, kind : String):
	String location
	String model_id
	String instance_of

	// Create model itself
	location = "models/" + cast_id(model)
	export_node(location, model["model"])

	model_id = instantiate_node(core, kind, "")
	instantiate_attribute(core, model_id, "name", store_entry(model_id, name, current_user_id))
	instantiate_attribute(core, model_id, "location", location)
	instantiate_attribute(core, model_id, "permissions", "200")
	instantiate_link(core, "owner", "", model_id, current_user_id)
	instantiate_link(core, "group", "", model_id, get_group_id("nobody"))
	instance_of = instantiate_link(core, "instanceOf", "", model_id, type_id)
	//instantiate_link(core, "semantics", "", instance_of, get_entry_id("models/conformance_mv"))

	// Create type mapping model
	instantiate_link(core, "typing", "", instance_of, export_typing(model, name))

	return!

Void function model_overwrite(model : Element, model_id : String, metamodel_id : String):
	// TODO this should be more elegant than just hiding the old elements

	String location
	String instanceOf_link

	location = "models/" + cast_id(model)
	export_node(location, model["model"])

	// Change location in meta-data
	unset_attribute(core, model_id, "location")
	instantiate_attribute(core, model_id, "location", location)

	// Update the instanceOf relation of the context in which we are working
	String choice
	choice = get_instanceOf_link(model_id, metamodel_id)
	if (element_neq(choice, read_root())):
		// There was a link, so we remove it

		// First remove the type mapping it referred to
		Element tl
		tl = allAssociationDestinations(core, choice, "typing")
		while (set_len(tl) > 0):
			model_delete_element(core, set_pop(tl))

		// Now delete the element itself
		model_delete_element(core, choice)

	// Create a new instanceOf relation now
	String instance_of
	instance_of = instantiate_link(core, "instanceOf", "", model_id, metamodel_id)
	//instantiate_link(core, "semantics", "", instance_of, get_entry_id("models/conformance_mv"))
	instantiate_link(core, "typing", "", instance_of, export_typing(model, full_name(model_id)))

	return!

Element function merge_models(models_dict : Element, operation_name : String):
	core = import_node(core_model_location)
	// 0) Find operation signature

	Element input_metamodels
	Element iter
	String edge
	String operation_id
	operation_id = get_entry_id(operation_name)

	input_metamodels = dict_create()
	iter = allOutgoingAssociationInstances(core, operation_id, "transformInput")
	while (set_len(iter) > 0):
		edge = set_pop(iter)
		dict_add(input_metamodels, read_attribute(core, edge, "name"), read_attribute(core, readAssociationDestination(core, edge), "name"))

	String merged_metamodel_id
	String trace_link_id
	Element trace_links

	// 1) Find merged metamodel
	trace_links = allOutgoingAssociationInstances(core, operation_id, "tracability")
	merged_metamodel_id = ""
	while (set_len(trace_links) > 0):
		trace_link_id = set_pop(trace_links)
		if (value_eq(read_attribute(core, trace_link_id, "type"), "operatesOn")):
			merged_metamodel_id = readAssociationDestination(core, trace_link_id)

	// 2) Merge source models
	if (merged_metamodel_id != ""):
		Element model_tuples
		Element keys
		String key
		Element mm

		model_tuples = set_create()
		keys = dict_keys(models_dict)
		while (set_len(keys) > 0):
			key = set_pop(keys)
			mm = get_full_model(get_entry_id(models_dict[key]), get_entry_id(input_metamodels[key]))
			if (element_eq(mm, read_root())):
				log("Signature mismatch in operation for tag " + key)
				output("Signature mismatch in operation for tag " + key)
				return read_root()!
			set_add_node(model_tuples, create_tuple(key, mm))

		Element merged_metamodel
		merged_metamodel = get_full_model(merged_metamodel_id, get_entry_id("SimpleClassDiagrams"))
		if (element_eq(merged_metamodel, read_root())):
			log("Merged metamodel in operation is not of type SimpleClassDiagrams")
			output("Type cannot be typed as formalisms/SimpleClassDiagrams: 'merged'")
			return read_root()!

		return model_join(model_tuples, merged_metamodel, read_root())!
	else:
		return read_root()!

Element function split_model(model : Element, metamodels_dict : Element):
	core = import_node(core_model_location)
	Element model_tuples
	Element keys
	String key
	Element mm

	model_tuples = set_create()
	keys = dict_keys(metamodels_dict)
	while (set_len(keys) > 0):
		key = set_pop(keys)
		mm = get_full_model(get_entry_id(metamodels_dict[key]), get_entry_id("SimpleClassDiagrams"))
		if (element_eq(mm, read_root())):
			log("Output metamodel cannot be interpreted using SimpleClassDiagrams: " + key)
			output("Type cannot be typed as formalisms/SimpleClassDiagrams: " + key)
			return read_root()!
		set_add_node(model_tuples, create_tuple(key, mm))

	return model_split(model, model_tuples, read_root())!

Boolean function check_conformance(model_id : String):
	// TODO check if it actually conforms, considering that instanceOf link
	//    --> in-depth check

	return True!

Element function get_model(model_name : String, metamodel_name : String):
	core = import_node(core_model_location)
	return get_full_model(get_entry_id(model_name), get_entry_id(metamodel_name))!

Void function store_model(model_name : String, metamodel_name : String, model : Element):
	core = import_node(core_model_location)
	if (get_entry_id(model_name) == ""):
		// New model
		model_create(model, model_name, get_entry_id(metamodel_name), "Model")
	else:
		model_overwrite(model, get_entry_id(model_name), get_entry_id(metamodel_name))
	return!

String function get_ramified_metamodel(model_name : String):
	core = import_node(core_model_location)
	String operation_id
	Element trace_links
	String merged_metamodel_id
	String trace_link_id
	String ramified_metamodel_id

	operation_id = get_entry_id(model_name)
	trace_links = allOutgoingAssociationInstances(core, operation_id, "tracability")
	merged_metamodel_id = ""

	while (set_len(trace_links) > 0):
		trace_link_id = set_pop(trace_links)

		if (value_eq(read_attribute(core, trace_link_id, "type"), "operatesOn")):
			merged_metamodel_id = readAssociationDestination(core, trace_link_id)
			trace_links = allOutgoingAssociationInstances(core, merged_metamodel_id, "tracability")
			ramified_metamodel_id = ""

			while (set_len(trace_links) > 0):
				trace_link_id = set_pop(trace_links)
				if (value_eq(read_attribute(core, trace_link_id, "type"), "RAMified")):
					ramified_metamodel_id = readAssociationDestination(core, trace_link_id)

					return read_attribute(core, ramified_metamodel_id, "name")!
	return read_root()!

Element function execute_operation(operation_id : String, input_models : Element, tracability_model : Element):
	// Operations are always in-place and uses only a single metamodel
	// Therefore, we must:
	//		1) Find merged metamodel
	// 		2) Merge the different source models and retype
	//		3) Perform the operation on the merged model
	//		4) Split the resulting model based on the target formalisms; if operation successful
	
	Element input_model
	String trace_link_id
	Element merged_model
	String merged_metamodel_id
	String ramified_metamodel_id
	Boolean result
	String exact_type
	Element trace_links
	String model_ID
	String key
	Element keys
	Element input_keys
	Element output_keys
	Element model_tuples
	String metamodel_name
	Element metamodel
	String metamodel_ID
	Boolean tracability

	// 0) Find the signature of the operation
	Element input_metamodels
	Element output_metamodels
	Element iter
	String edge
	input_metamodels = dict_create()
	iter = allOutgoingAssociationInstances(core, operation_id, "transformInput")
	while (set_len(iter) > 0):
		edge = set_pop(iter)
		dict_add(input_metamodels, read_attribute(core, edge, "name"), full_name(readAssociationDestination(core, edge)))

	output_metamodels = dict_create()
	iter = allOutgoingAssociationInstances(core, operation_id, "transformOutput")
	while (set_len(iter) > 0):
		edge = set_pop(iter)
		dict_add(output_metamodels, read_attribute(core, edge, "name"), full_name(readAssociationDestination(core, edge)))

	// 1) Find merged metamodel

	exact_type = read_type(core, operation_id)
	trace_links = allOutgoingAssociationInstances(core, operation_id, "tracability")
	merged_metamodel_id = ""
	while (set_len(trace_links) > 0):
		trace_link_id = set_pop(trace_links)
		if (value_eq(read_attribute(core, trace_link_id, "type"), "operatesOn")):
			merged_metamodel_id = readAssociationDestination(core, trace_link_id)

	// 2) Merge source models

	if (merged_metamodel_id != ""):
		model_tuples = set_create()
		keys = dict_keys(input_models)
		while (set_len(keys) > 0):
			key = set_pop(keys)
			Element mm
			if (get_entry_id(input_models[key]) == ""):
				// Input model doesn't exist yet, so create
				cmd_model_add(input_metamodels[key], input_models[key], "")
			mm = get_full_model(get_entry_id(input_models[key]), get_entry_id(input_metamodels[key]))
			if (element_eq(mm, read_root())):
				return "Signature mismatch in operation for tag: " + key!
			set_add_node(model_tuples, create_tuple(key, mm))

		Element merged_metamodel
		merged_metamodel = get_full_model(merged_metamodel_id, get_entry_id("formalisms/SimpleClassDiagrams"))
		if (element_eq(merged_metamodel, read_root())):
			return "Type cannot be typed as formalisms/SimpleClassDiagrams: 'merged'"!

		merged_model = model_join(model_tuples, merged_metamodel, tracability_model)
	else:
		if (bool_and(dict_len(input_models) == 1, dict_len(output_metamodels) == 0)):
			// Just skip the merge...
			Element m
			m = get_full_model(get_entry_id(input_models[set_pop(dict_keys(input_models))]), get_entry_id(input_metamodels[set_pop(dict_keys(input_metamodels))]))
			if (element_eq(m, read_root())):
				return "Signature mismatch in operation for tag: " + cast_value(set_pop(dict_keys(input_models)))!
			merged_model = model_copy(m)
		elif (bool_and(dict_len(input_models) == 0, dict_len(output_metamodels) == 0)):
			merged_model = read_root()
		else:
			return "Could not resolve intermediate merged metamodel"!

	// 3) Transform

	if (exact_type == "ModelTransformation"):
		trace_links = allOutgoingAssociationInstances(core, merged_metamodel_id, "tracability")
		ramified_metamodel_id = ""
		while (set_len(trace_links) > 0):
			trace_link_id = set_pop(trace_links)
			if (value_eq(read_attribute(core, trace_link_id, "type"), "RAMified")):
				ramified_metamodel_id = readAssociationDestination(core, trace_link_id)

		Element operation
		operation = get_full_model(operation_id, ramified_metamodel_id)
		if (element_eq(operation, read_root())):
			return "Operation could not be typed by specified RAMified metamodel!"!
		result = transform(merged_model, operation)
	elif (exact_type == "ManualOperation"):
		output("Please perform manual operation " + cast_value(full_name(operation_id)))
		log("Performing manual")
		if (element_neq(merged_model, read_root())):
			String model_name
			model_name = ""
			while (get_entry_id(model_name) != ""):
				model_name = "tmp/" + random_string(20)
			model_create(merged_model, model_name, merged_metamodel_id, "Model")
			// We want to modify, so modify
			do_spawn_modify(model_name, True)
			merged_model = get_full_model(get_entry_id(model_name), merged_metamodel_id)
			//model_delete(get_entry_id(model_name))
			result = True
		else:
			output("Nothing to modify")
			return True!
	elif (exact_type == "ActionLanguage"):
		Element func
		Element al
		al = get_full_model(operation_id, get_entry_id("formalisms/ActionLanguage"))
		if (element_eq(al, read_root())):
			return "Action Language operation not typed by ActionLanguage metamodel!"!
		func = get_func_AL_model(al)
		result = func(merged_model)
	else:
		return "Unknown type of operation: " + exact_type!

	// 4) Split in different models depending on type

	if (element_neq(tracability_model, read_root())):
		tracability = True
	else:
		tracability = False

	if (result):
		model_tuples = set_create()
		keys = dict_keys(output_metamodels)
		while (set_len(keys) > 0):
			key = set_pop(keys)
			Element mm
			mm = get_full_model(get_entry_id(output_metamodels[key]), get_entry_id("formalisms/SimpleClassDiagrams"))
			if (element_eq(mm, read_root())):
				return "Type cannot be typed as formalisms/SimpleClassDiagrams: " + key!
			set_add_node(model_tuples, create_tuple(key, mm))

		result = model_split(merged_model, model_tuples, tracability)

		if (tracability):
			Element new_tracability_model
			new_tracability_model = result["__tracability"]
			dict_overwrite(tracability_model, "model", new_tracability_model["model"])
			set_type_mapping(tracability_model, get_type_mapping(new_tracability_model))
			dict_overwrite(tracability_model, "metamodel", new_tracability_model["metamodel"])
			dict_delete(result, "__tracability")

		return result!
	else:
		return "Failure"!

Boolean function enact_action(pm : Element, element : String, mapping : Element):
	Boolean result
	String transformation_id
	Element lst
	String elem
	Element inputs
	Element outputs
	String type_name
	String exact_type
	Element trace_links
	Element output_mms
	Element consumes_link
	String name
	String elem_name
	Element keys
	String key
	String consume
	String produce
	Element input_traceability_model
	String output_traceability_name
	String output_traceability_type
	Element output_map

	inputs = dict_create()
	outputs = dict_create()
	output_map = dict_create()
	input_traceability_model = read_root()
	output_traceability_name = read_root()
	output_traceability_type = read_root()

	// Read out the referenced element from the MvC
	transformation_id = get_entry_id(read_attribute(pm, element, "name"))

	// Find all input model names
	lst = allOutgoingAssociationInstances(pm, element, "Consumes")
	while (set_len(lst) > 0):
		consume = set_pop(lst)
		elem = readAssociationDestination(pm, consume)
		type_name = read_attribute(pm, elem, "type")
		elem_name = read_attribute(pm, elem, "name")
		if (cast_string(read_attribute(pm, consume, "name")) == "__traceability"):
			input_traceability_model = model_copy(get_full_model(get_entry_id(mapping[elem_name]), get_entry_id(type_name)))
			output_traceability_type = type_name
		else:
			dict_add(inputs, read_attribute(pm, consume, "name"), mapping[elem_name])

	// Find all output model names and their metamodel
	lst = allOutgoingAssociationInstances(pm, element, "Produces")
	while (set_len(lst) > 0):
		produce = set_pop(lst)
		elem = readAssociationDestination(pm, produce)
		type_name = read_attribute(pm, elem, "type")
		elem_name = read_attribute(pm, elem, "name")
		if (cast_string(read_attribute(pm, produce, "name")) == "__traceability"):
			output_traceability_name = mapping[elem_name]
		else:
			dict_add(outputs, read_attribute(pm, produce, "name"), type_name)
			dict_add(output_map, read_attribute(pm, produce, "name"), mapping[elem_name])

	if read_type(core, transformation_id) == "ActionLanguage":
		log(string_join("Enacting ActionLanguage: ", read_attribute(pm, element, "name")))
		output("Success: ready for AL execution")
	elif read_type(core, transformation_id) == "ManualOperation":
		log(string_join("Enacting ManualOperation: ", read_attribute(pm, element, "name")))
		output("Success: ready for MANUAL execution")
	else:
		log(string_join("Enacting ModelTransformation: ", read_attribute(pm, element, "name")))
		output("Success: ready for MT execution")

	result = execute_operation(transformation_id, inputs, input_traceability_model)

	log(string_join("Finished: ", read_attribute(pm, element, "name")))

	if (is_physical_string(result)):
		// Something went wrong!
		output("Failure")
		return False!
	else:
		// Check if we have to store traceability information
		if (element_neq(output_traceability_name, read_root())):
			// Yes, so store it
			// Note that we have overwritten the previous input traceability model, which is why it was a copy
			model_overwrite(input_traceability_model, get_entry_id(output_traceability_name), get_entry_id(output_traceability_type))

		keys = dict_keys(outputs)
		while (set_len(keys) > 0):
			key = set_pop(keys)
			if (get_entry_id(output_map[key]) == ""):
				// New model
				model_create(result[key], output_map[key], get_entry_id(outputs[key]), "Model")
			else:
				model_overwrite(result[key], get_entry_id(output_map[key]), get_entry_id(outputs[key]))
		output("Success")
		return True!

Element function PM_signature(pm : Element):
	Element all_data
	Element result
	String entry

	result = dict_create()
	all_data = allInstances(pm, "Data")
	while (set_len(all_data) > 0):
		entry = set_pop(all_data)
		dict_add(result, cast_string(read_attribute(pm, entry, "name")), cast_string(read_attribute(pm, entry, "type")))

	return result!

Void function enact_PM_activity(activity_to_task : Element, task_to_result : Element, pm : Element, element : String, mapping : Element):
	Boolean result
	pm_tasks = activity_to_task
	set_add(activity_to_task[element], get_taskname())
	result = enact_action(pm, element, mapping)
	dict_add_fast(task_to_result, get_taskname(), result)

	while (other_has_output(get_taskname())):
		sleep(1)

	return!

Void function enact_PM(pm : Element, mapping : Element):
	Element worklist
	String element
	String type
	Boolean result
	Element tuple
	Element counters
	Element join_nodes
	Element exec_nodes
	Element keys
	String key

	output("Success")

	// For all entries in the signature, not in the mapping, we add a mock location
	Element signature
	String mock_location
	Element mock_locations
	mock_locations = set_create()
	signature = PM_signature(pm)
	keys = dict_keys(signature)
	while (set_len(keys) > 0):
		key = set_pop(keys)
		if (bool_not(dict_in(mapping, key))):
			// Add mock location
			mock_location = ""
			while (get_entry_id(mock_location) != ""):
				mock_location = "tmp/" + random_string(10)
			dict_add(mapping, key, mock_location)
			cmd_model_add(signature[key], mapping[key], "")
			set_add(mock_locations, mock_location)

	// Initialize Join counters
	counters = dict_create()
	join_nodes = allInstances(pm, "Join")
	while (set_len(join_nodes) > 0):
		dict_add(counters, set_pop(join_nodes), 0)

	// Initialize activity to task dictionary with empty sets
	Element activity_to_task
	Element task_to_activity
	Element task_to_result

	activity_to_task = dict_create()
	task_to_activity = dict_create()
	task_to_result = dict_create()
	exec_nodes = allInstances(pm, "Exec")
	while (set_len(exec_nodes) > 0):
		dict_add(activity_to_task, set_pop(exec_nodes), set_create())

	// Create the worklist with the Start instance as first element
	worklist = list_create()
	list_append(worklist, set_pop(allInstances(pm, "Start")))

	// Keep on iterating until we reach finish
	while (True):
		// Check if there are PM elements to expand
		if (list_len(worklist) > 0):
			// There is something we can do, so do it!
			element = list_pop_final(worklist)

			// Find the type (to see what to do with it)
			//   this does not yet yield the type of transformation, if it is an Execution
			type = read_type(pm, element)

			// Some types have nothing to do, such as start and fork
			// Therefore, they are not mentioned in the following conditional

			if (type == "Finish"):
				// We have finished, so terminate
				break!
			elif (type == "Join"):
				// Only do this if all dependencies are fullfilled
				// So add to the counter of this Join
				dict_overwrite(counters, element, integer_addition(counters[element], 1))

				// Now check whether we have enough tokens to execute the Join itself
				Integer required
				Integer got
				required = set_len(allIncomingAssociationInstances(pm, element, "Next")) + set_len(allIncomingAssociationInstances(pm, element, "Else")) + set_len(allIncomingAssociationInstances(pm, element, "Then"))
				got = counters[element]
				if (got == required):
					// Reset counter to 0
					dict_overwrite(counters, element, 0)

					// And continue
				else:
					// We haven't gotten all yet, so we wait (i.e., continue without adding Next link to worklist)
					continue!

			elif (type == "Exec"):
				// Execute a transformation
				// This the difficult part!

				Element args
				String taskname
				args = list_create()
				list_append(args, activity_to_task)
				list_append(args, task_to_result)
				list_append(args, pm)
				list_append(args, element)
				list_append(args, mapping)
				taskname = spawn(enact_PM_activity, args)
				output(taskname + " : " + cast_string(read_attribute(pm, element, "name")))
				dict_add(task_to_activity, taskname, element)
				continue!

			// We have finished the execution, so add all outgoing edges to the worklist
			Element all_next
			all_next = allAssociationDestinations(pm, element, "Next")
			String next
			while (set_len(all_next) > 0):
				next = set_pop(all_next)
				list_append(worklist, next)
		else:
			// No new tasks to spawn, so go and check on all running activities
			if (dict_len(task_to_result) > 0):
				// There are outputs!
				Element keys
				String task

				keys = dict_keys(task_to_result)
				while (set_len(keys) > 0):
					task = set_pop(keys)
					result = task_to_result[task]

					Element all_next
					all_next = allAssociationDestinations(pm, task_to_activity[task], "Next")
					String next
					while (set_len(all_next) > 0):
						next = set_pop(all_next)

						if (read_type(pm, next) == "Decision"):
							// Got decision node, so expand immediately
							if (result):
								list_append(worklist, anAssociationDestination(pm, next, "Then"))
							else:
								list_append(worklist, anAssociationDestination(pm, next, "Else"))
						else:
							// Other node, so just append for further processing
							list_append(worklist, next)

					set_remove(activity_to_task[task_to_activity[task]], task)
					dict_delete(task_to_result, task)
					dict_delete(task_to_activity, task)
			else:
				// No finished activities either, so we sleep for some time
				sleep(0.1)

	// Remove all mock locations again
	while (set_len(mock_locations) > 0):
		model_delete(get_entry_id(set_pop(mock_locations)))

	return !

String function cmd_AL_text(location : String):
	if location == "":
		return "Success: \n"!
	else:
		if (element_eq(import_node(location + "/__text"), read_root())):
			return "Unknown location: " + cast_string(location)!
		else:
			return "Success: " + cast_string(import_node(location + "/__text"))!

String function cmd_help():
	String result

	result = ""
	result = result + ("Model operations\n")
	result = result + ("    model_add                       -- Add a new model\n")
	result = result + ("    model_move                      -- Move a model to a different location\n")
	result = result + ("    model_modify                    -- Modify an existing model\n")
	result = result + ("    model_list                      -- List all models\n")
	result = result + ("    model_list_full                 -- List all models with full info\n")
	result = result + ("    model_overwrite                 -- Overwrites a model with an uploaded model, leaving all metadata\n")
	result = result + ("    model_render                    -- Render a given model with a specified mapper\n")
	result = result + ("    verify                          -- Check whether a model conforms to its metamodel\n")
	result = result + ("\n")
	result = result + ("Transformation-specific operations\n")
	result = result + ("    transformation_add_MT           -- Initialize a new model transformation\n")
	result = result + ("    transformation_add_AL           -- Initialize a new action language transformation\n")
	result = result + ("    transformation_add_MANUAL       -- Initialize a new manual transformation\n")
	result = result + ("    transformation_execute          -- Execute a transformation on a set of input models\n")
	result = result + ("    transformation_list             -- List all model transformations\n")
	result = result + ("    transformation_list_full        -- List all model transformations with permissions\n")
	result = result + ("    transformation_detail           -- List transformation details\n")
	result = result + ("    transformation_between          -- List all transformations between two metamodels\n")
	result = result + ("\n")
	result = result + ("Process operations\n")
	result = result + ("    process_execute                 -- Execute a process model\n")
	result = result + ("\n")
	result = result + ("Model permission operations\n")
	result = result + ("    permission_modify               -- Change model permissions\n")
	result = result + ("    permission_owner                -- Change model owner\n")
	result = result + ("    permission_group                -- Change model group\n")
	result = result + ("\n")
	result = result + ("Group operations\n")
	result = result + ("    group_create                    -- Create a group\n")
	result = result + ("    group_delete                    -- Delete a group\n")
	result = result + ("    group_owner_add                 -- Add group owner\n")
	result = result + ("    group_owner_delete              -- Remove group owner\n")
	result = result + ("    group_join                      -- Add someone to your group\n")
	result = result + ("    group_kick                      -- Kick someone from your group\n")
	result = result + ("    group_list                      -- List all groups you are a member of\n")
	result = result + ("\n")

	if (is_admin(current_user_id)):
		result = result + ("Admin operations\n")
		result = result + ("    admin_promote                   -- Promote a user to admin status\n")
		result = result + ("    admin_demote                    -- Demote a user to normal status\n")
		result = result + ("\n")

	result = result + ("General operations\n")
	result = result + ("    exit                            -- Kill the current task, while retaining user\n")

	return result!

String function cmd_model_move(source : String, target : String):
	String source_id
	source_id = get_entry_id(source)
	if (source_id != ""):
		if (allow_write(current_user_id, source_id)):
			if (get_entry_id(target) == ""):
				// Create folders on path to the target
				if (element_neq(create_folders(current_user_id, get_foldername(target)), read_root())):
					if (allow_write(current_user_id, get_entry_id(get_foldername(target)))):
						// Change location, first the name
						instantiate_attribute(core, source_id, "name", target)

						// Now the folder links
						Element links
						links = allIncomingAssociationInstances(core, source_id, "contains")
						while (set_len(links) > 0):
							model_delete_element(core, set_pop(links))
						instantiate_link(core, "contains", "", get_entry_id(get_foldername(target)), source_id)

						// Flush caches
						dict_add(caches["models"], target, caches["models"][source])
						dict_delete(caches["models"], source)

						// Done
						return "Success"!
					else:
						return "Write permission denied to: " + target!
				else:
					return "Write permission denied to: " + target!
			else:
				return "Model exists: " + target!
		else:
			return "Write permission denied to: " + source!
	else:
		return "Model not found: " + source!

String function cmd_model_add(type : String, name : String, code : String):
	// Model addition operation, which uses model upload commands of the compiler
	String location
	String type_id
	Element new_model
	String new_model_id
	Element mm

	type_id = get_entry_id(type)
	if (type_id != ""):
		// Type exists
		if (allow_read(current_user_id, type_id)):
			if (read_type(core, type_id) != "Folder"):
				// And is readable
				mm = get_full_model(type_id, get_entry_id("formalisms/SimpleClassDiagrams"))
				if (element_neq(mm, read_root())):
					if (element_neq(create_folders(current_user_id, get_foldername(name)), read_root())):
						if (allow_write(current_user_id, get_entry_id(get_foldername(name)))):
							if (get_entry_id(name) == ""):
								// Model doesn't exist yet
								new_model = compile_model(code, mm)

								if (is_physical_string(new_model)):
									return "Compilation error: " + cast_string(new_model)!

								model_create(new_model, name, type_id, "Model")
								return "Success"!
							else:
								return "Model exists: " + name!
						else:
							return "Write permission denied to: " + name!
					else:
						return "Write permission denied to: " + name!
				else:
					return "Type cannot be typed as formalisms/SimpleClassDiagrams: " + type!
			else:
				return "Not a model: " + type!
		else:
			return "Read permission denied to: " + type!
	else:
		return "Model not found: " + type!

String function cmd_process_execute(process : String, mapping : Element):
	// Execute a process model until it reaches termination
	String process_id
	String name

	process_id = get_entry_id(process)
	if (process_id != ""):
		if (read_type(core, process) != "Folder"):
			if (allow_execute(current_user_id, process_id)):
				Element pm
				pm = get_full_model(process_id, get_entry_id("formalisms/ProcessModel"))
				if (element_eq(pm, read_root())):
					return "Not a ProcessModel: " + process!

				String ver
				ver = conformance_scd(pm)
				if (ver == "OK"):
					Element all_data
					String data
					Element names
					all_data = allInstances(pm, "Data")
					names = set_create()
					while (set_len(all_data) > 0):
						data = set_pop(all_data)
						set_add(names, read_attribute(pm, data, "name"))
						if (set_len(allIncomingAssociationInstances(pm, data, "Consumes")) > 0):
							name = read_attribute(pm, data, "name")
							// It is used somewhere for consumption: require read permissions
							// First check if this is a defined name
							if (dict_in(mapping, name)):
								// Yes, it is defined seperately, so we have to check
								if (get_entry_id(mapping[name]) != ""):
									// Existing model, so have to check
									if (bool_not(allow_read(current_user_id, get_entry_id(mapping[name])))):
										// Not readable model, while it has to be read: error
										return "Read permission denied to: " + cast_string(mapping[name])!
									if (read_type(core, mapping[name]) == "Folder"):
										return "Not a model: " + cast_string(mapping[name])!
						if (set_len(allIncomingAssociationInstances(pm, data, "Produces")) > 0):
							name = read_attribute(pm, data, "name")
							// It is used somewhere for consumption: require read permissions
							// First check if this is a defined name
							if (dict_in(mapping, name)):
								// Yes, it is defined seperately, so we have to check
								if (get_entry_id(mapping[name]) != ""):
									// Existing model, so have to check
									if (bool_not(allow_write(current_user_id, get_entry_id(mapping[name])))):
										// Not readable model, while it has to be read: error
										return "Write permission denied to: " + cast_string(mapping[name])!
									if (read_type(core, mapping[name]) == "Folder"):
										return "Not a model: " + cast_string(mapping[name])!

					// Now check all keys in the mapping
					Element map_keys
					map_keys = dict_keys(mapping)
					if (set_len(set_difference(map_keys, names)) > 0):
						return "Signature mismatch: " + cast_string(set_pop(set_difference(map_keys, names)))!

					// Now execute!
					enact_PM(pm, mapping)
					return "Success"!
				else:
					return "Not a valid ProcessModel: " + ver!
			else:
				return "Execute permission denied to: " + process!
		else:
			return "Not a model: " + process!
	else:
		return "Model not found: " + process!

String function cmd_process_signature(process : String):
	// Execute a process model until it reaches termination
	String process_id
	String result
	Element signature
	Element keys
	String key

	process_id = get_entry_id(process)
	if (process_id != ""):
		if (allow_execute(current_user_id, process_id)):
			if (read_type(core, process_id) == "Model"):
				Element pm
				pm = get_full_model(process_id, get_entry_id("formalisms/ProcessModel"))
				
				if (element_eq(pm, read_root())):
					return "Not a ProcessModel: " + process!

				result = "Success: "
				signature = PM_signature(pm)
				keys = dict_keys(signature)
				Element found_keys
				found_keys = set_create()
				while (set_len(keys) > 0):
					key = set_pop(keys)
					result = result + key + " : " + cast_string(signature[key]) + "\n"
					if set_in(found_keys, key):
						return "Not a valid ProcessModel: " + process!
					else:
						set_add(found_keys, key)

				return result!
			else:
				return "Not a model: " + process!
		else:
			return "Execute permission denied to: " + process!
	else:
		return "Model not found: " + process!

String function cmd_transformation_between(source_dict : String, target_dict : String):
	Element result
	Element subresult
	String tag
	String mm
	String mm_id
	Element links
	String link
	Element keys

	if (dict_len(source_dict) + dict_len(target_dict) == 0):
		return "Incorrect format: cannot resolve empty input and output list as this would return all transformations."!

	result = allInstances(core, "Transformation")

	// Iterate over all inputs
	keys = dict_keys(source_dict)
	while (set_len(keys) > 0):
		subresult = set_create()
		tag = set_pop(keys)
		mm = source_dict[tag]
		mm_id = get_entry_id(mm)

		if (mm_id != ""):
			if (read_type(core, mm_id) != "Folder"):
				links = allIncomingAssociationInstances(core, mm_id, "transformInput")

				while (set_len(links) > 0):
					link = set_pop(links)
					if (value_eq(read_attribute(core, link, "name"), tag)):
						// Correct tag, so make transformation a possibility
						set_add(subresult, readAssociationSource(core, link))
			else:
				return "Not a model: " + mm!
		else:
			return "Model not found: " + mm!

		// Got a set of subresults now, which we use to find the overlap
		result = set_overlap(result, subresult)

	keys = dict_keys(target_dict)
	while (set_len(keys) > 0):
		subresult = set_create()
		tag = set_pop(keys)
		mm = target_dict[tag]
		mm_id = get_entry_id(mm)

		if (mm_id != ""):
			if (read_type(core, mm_id) != "Folder"):
				links = allIncomingAssociationInstances(core, mm_id, "transformOutput")

				while (set_len(links) > 0):
					link = set_pop(links)
					if (value_eq(read_attribute(core, link, "name"), tag)):
						// Correct tag, so make transformation a possibility
						set_add(subresult, readAssociationSource(core, link))
			else:
				return "Not a model: " + mm!
		else:
			return "Model not found: " + mm!

		// Got a set of subresults now, which we use to find the overlap
		result = set_overlap(result, subresult)

	String r
	String transformation
	r = "Success: "
	while (set_len(result) > 0):
		transformation = set_pop(result)
		if (allow_read(current_user_id, transformation)):
			r = r + string_join(full_name(transformation), "\n")
	return r!

String function cmd_model_rendered(model_name : String, mapper_name : String):
	Element trace_links
	String rendered
	String trace_link_id
	String allowed_rendered
	Element trace_links_2
	String trace_link_2_id

	allowed_rendered = "Success: "
	trace_links = allOutgoingAssociationInstances(core, get_entry_id(model_name), "tracability")
	while (set_len(trace_links) > 0):
		trace_link_id = set_pop(trace_links)
		if (value_eq(read_attribute(core, trace_link_id, "type"), "CS_perceptualized")):
			rendered = readAssociationDestination(core, trace_link_id)
			trace_links_2 = allOutgoingAssociationInstances(core, rendered, "tracability")
			while (set_len(trace_links_2) > 0):
				trace_link_2_id = set_pop(trace_links_2)
				if (value_eq(read_attribute(core, readAssociationDestination(core, trace_link_2_id), "name"), mapper_name)):
					if (value_eq(read_attribute(core, trace_link_2_id, "type"), "CS_mapper")):
						allowed_rendered = string_join(allowed_rendered, read_attribute(core, rendered, "name")) + "\n"

	return allowed_rendered!

String function cmd_model_render(model_name : String, mapper_name : String, rendered_name : String):
	String model_ID
	String mapper_ID
	String tracability_name
	Element inputs
	Element output_map
	Element rendered_model
	Element tracability_model
	Element result
	Element out_links
	String link

	String ID_rendered_M
	String ID_rendered_MM
	String ID_SCD
	String ID_tracability_MM
	String ID_tracability_M

	model_ID = get_entry_id(model_name)

	if (model_ID != ""):
		mapper_ID = get_entry_id(mapper_name)

		if (allow_read(current_user_id, model_ID)):
			if (mapper_ID != ""):
				if (allow_execute(current_user_id, mapper_ID)):
					// Everything is fine; start the actual operation
					// Find metamodel to render to
					tracability_name = "tmp/" + rendered_name

					// Take the abstract syntax model and the previously rendered model
					inputs = dict_create()
					dict_add(inputs, "abstract", model_name)
					dict_add(inputs, "rendered", rendered_name)

					// Fetch the output types
					output_map = dict_create()
					out_links = allOutgoingAssociationInstances(core, mapper_ID, "transformOutput")
					while(set_len(out_links) > 0):
						link = set_pop(out_links)
						dict_add(output_map, read_attribute(core, link, "name"), full_name(readAssociationDestination(core, link)))

					ID_rendered_MM = get_entry_id(output_map["rendered"])
					ID_SCD = get_entry_id("formalisms/SimpleClassDiagrams")
					ID_tracability_MM = get_entry_id("formalisms/Tracability")
					ID_tracability_M = get_entry_id(tracability_name)
					ID_rendered_M = get_entry_id(rendered_name)

					if (ID_rendered_M == ""):
						// Instantiate
						Element rendered
						rendered = get_full_model(ID_rendered_MM, ID_SCD)
						if (element_eq(rendered, read_root())):
							return "Type cannot be typed as formalisms/SimpleClassDiagrams: 'rendered'"!

						rendered_model = instantiate_model(rendered)

						model_create(rendered_model, rendered_name, ID_rendered_MM, "Model")
						
						// Tracability model won't exist either
						tracability_model = instantiate_model(get_full_model(ID_tracability_MM, ID_SCD))
						model_create(tracability_model, tracability_name, ID_tracability_MM, "Model")

						ID_rendered_M = get_entry_id(rendered_name)
						ID_tracability_M = get_entry_id(tracability_name)

					else:
						// Read out tracability model
						tracability_model = get_full_model(ID_tracability_M, ID_tracability_MM)
						if (element_eq(tracability_model, read_root())):
							return "Tracability model not typed by Tracability metamodel: " + tracability_name!

					// Do the operation itself!
					result = execute_operation(mapper_ID, inputs, tracability_model)

					// Overwrite the previous rendered model
					model_overwrite(result["rendered"], ID_rendered_M, ID_rendered_MM)

					// Tracability updated in-place
					model_overwrite(tracability_model, ID_tracability_M, ID_tracability_MM)
					if (element_eq(tracability_model, read_root())):
						return "Tracability model not typed by Tracability metamodel: " + tracability_name!

					// Link all information in the megamodel
					String tr_link
					tr_link = instantiate_link(core, "tracability", "", get_entry_id(model_name), ID_rendered_M)
					instantiate_attribute(core, tr_link, "type", "CS_perceptualized")
					tr_link = instantiate_link(core, "tracability", "", ID_rendered_M, get_entry_id(mapper_name))
					instantiate_attribute(core, tr_link, "type", "CS_mapper")

					// Output the resulting model
					String value
					value = JSON_print(result["rendered"])
					return ("Success: " + value) !
				else:
					return "Execute permission denied to: " + mapper_name!
			else:
				return "Model not found: " + mapper_name!
		else:
			return "Read permission denied to: " + model_name!
	else:
		return "Model not found: " + model_name!

Boolean function do_spawn_modify(model_name : String, write : Boolean):
	output("Please edit this model before sending next input: " + model_name)
	input()
	return False!

String function do_spawn_activity(transformation_id : String, tracability_name : String, inputs : Element, outputs : Element, output_map : Element):
	Element lst
	Element returnvalue
	String taskname

	lst = list_create()
	returnvalue = set_create()
	list_append(lst, returnvalue)
	list_append(lst, transformation_id)
	list_append(lst, tracability_name)
	list_append(lst, inputs)
	list_append(lst, outputs)
	list_append(lst, output_map)
	taskname = spawn(spawn_activity, lst)

	output("Spawned activity on task: " + taskname)

	while (set_len(returnvalue) == 0):
		sleep(0.1)

	output("Finished task: " + taskname)
	return set_pop(returnvalue)!

Void function spawn_activity(returnvalue : Element, transformation_id : String, tracability_name : String, inputs : Element, outputs : Element, output_map : Element):
	Element result
	Element keys
	String key

	if (read_type(core, transformation_id) == "ActionLanguage"):
		output("Success: ready for AL execution")
	elif (read_type(core, transformation_id) == "ManualOperation"):
		output("Success: ready for MANUAL execution")
	else:
		output("Success: ready for MT execution")

	// Do tracability
	Element tracability_model
	if (tracability_name != ""):
		// Check if exists
		if (get_entry_id(tracability_name) == ""):
			// No, so create
			tracability_model = instantiate_model(get_full_model(get_entry_id("formalisms/Tracability"), get_entry_id("formalisms/SimpleClassDiagrams")))
			model_create(tracability_model, tracability_name, get_entry_id("formalisms/Tracability"), "Model")
		else:
			// Yes, so read out
			tracability_model = get_full_model(get_entry_id(tracability_name), get_entry_id("formalisms/Tracability"))
	else:
		tracability_model = read_root()

	result = execute_operation(transformation_id, inputs, tracability_model)

	// Flush tracability again, just to be sure
	if (tracability_name != ""):
		model_overwrite(tracability_model, get_entry_id(tracability_name), get_entry_id("formalisms/Tracability"))

	// Now write out the models again
	if (is_physical_string(result)):
		// Something went wrong!
		set_add(returnvalue, result)
		output("Nothing to modify")
	else:
		keys = dict_keys(outputs)
		while (set_len(keys) > 0):
			key = set_pop(keys)
			
			if (get_entry_id(outputs[key]) == ""):
				// New model
				model_create(result[key], outputs[key], get_entry_id(output_map[key]), "Model")
			else:
				model_overwrite(result[key], get_entry_id(outputs[key]), get_entry_id(output_map[key]))

		set_add(returnvalue, "Success")
		output("Success")

	while (other_has_output(get_taskname())):
		sleep(1)

	return!

String function cmd_transformation_execute(transformation_name : String, source_models : Element, target_models : Element, tracability_name : String):
	// Execute a transformation, whatever type it is
	// First we detect the type, so we know how to prepare for invocation
	String transformation_id
	String exact_type
	Element sources
	Element targets
	String source
	String target
	Element inputs
	Element outputs
	Element output_map
	Element trace_links
	String target_model_name
	String source_model_name
	String source_model_ID
	String assoc_name

	transformation_id = get_entry_id(transformation_name)
	if (transformation_id != ""):
		if (allow_execute(current_user_id, transformation_id)):
			if (is_nominal_instance(core, transformation_id, "Transformation")):
				// Read out source and target links
				inputs = dict_create()

				sources = allOutgoingAssociationInstances(core, transformation_id, "transformInput")
				while (set_len(sources) > 0):
					source = set_pop(sources)
					assoc_name = read_attribute(core, source, "name")
					if (dict_in(source_models, assoc_name)):
						source_model_name = source_models[assoc_name]
					else:
						return "Source model not bound: " + assoc_name!

					source_model_ID = get_entry_id(source_model_name)
					if (source_model_ID != ""):
						if (allow_read(current_user_id, source_model_ID)):
							if (read_type(core, source_model_ID) != "Folder"):
								// Check for conformance to the requested metamodel
								dict_add(inputs, assoc_name, source_model_name)
								continue!
							else:
								return "Not a model: " + source_model_name!
						else:
							return "Read permission denied to: " + source_model_name!
					else:
						return "Model not found: " + source_model_name!

				Element diff
				diff = set_difference(dict_keys(source_models), dict_keys(inputs))
				if (set_len(diff) > 0):
					return "Source model not bound: " + cast_string(set_pop(diff))!

				targets = allOutgoingAssociationInstances(core, transformation_id, "transformOutput")
				outputs = dict_create()
				output_map = dict_create()
				while (set_len(targets) > 0):
					target = set_pop(targets)
					assoc_name = read_attribute(core, target, "name")
					if (dict_in(target_models, assoc_name)):
						target_model_name = target_models[assoc_name]

						if (get_entry_id(target_model_name) == ""):
							// Doesn't exist yet, so we can easily create
							if (get_entry_id(get_foldername(target_model_name)) == ""):
								return "Model not found: " + get_foldername(target_model_name)!
							else:
								if (allow_write(current_user_id, get_entry_id(get_foldername(target_model_name)))):
									dict_add(output_map, assoc_name, full_name(readAssociationDestination(core, target)))
									dict_add(outputs, assoc_name, target_model_name)
								else:
									return "Write permission denied to: " + get_foldername(target_model_name)!
						else:
							// Already exists, so we need to check for write access
							if (read_type(core, get_entry_id(target_model_name)) == "Folder"):
								// Is a folder, so reject
								return "Not a model: " + target_model_name!
							else:
								if (allow_write(current_user_id, get_entry_id(target_model_name))):
									dict_add(output_map, assoc_name, read_attribute(core, readAssociationDestination(core, target), "name"))
									dict_add(outputs, assoc_name, target_model_name)
								else:
									return "Write permission denied to: " + target_model_name!

				diff = set_difference(dict_keys(target_models), dict_keys(outputs))
				if (set_len(diff) > 0):
					return "Target model not bound: " + cast_string(set_pop(diff))!

				return do_spawn_activity(transformation_id, tracability_name, inputs, outputs, output_map)!
			else:
				return "Execute permission denied to: " + transformation_name!
		else:
			return "Execute permission denied to: " + transformation_name!
	else:
		return "Model not found: " + transformation_name!

String function cmd_verify(model_name : String, metamodel_name : String):
	// Check whether a model conforms to its specification (with the selected type mapping)
	String model_id
	String result
	Element inputs

	model_id = get_entry_id(model_name)
	if (model_id != ""):
		if (allow_read(current_user_id, model_id)):
			if (read_type(core, model_id) != "Folder"):
				if (get_entry_id(metamodel_name) != ""):
					if (read_type(core, get_entry_id(metamodel_name)) != "Folder"):
						if (allow_read(current_user_id, get_entry_id(metamodel_name))):
							Element m
							m = get_full_model(get_entry_id(model_name), get_entry_id(metamodel_name))
							if (element_eq(m, read_root())):
								return "Conformance hierarchy unknown for: " + model_name!

							return string_join("Success: ", conformance_scd(m))!
						else:
							return "Read permission denied to: " + metamodel_name!
					else:
						return "Not a model: " + metamodel_name!
				else:
					return "Model not found: " + metamodel_name!
			else:
				return "Not a model: " + model_name!
		else:
			return "Read permission denied to: " + model_name!
	else:
		return "Model not found: " + model_name!

String function cmd_model_overwrite(model_name : String, metamodel_name : String):
	// Overwrites an existing model without changing any metadata
	String model_id
	String type_id
	Element new_model

	model_id = get_entry_id(model_name)
	if (model_id != ""):
		if (allow_write(current_user_id, model_id)):
			type_id = anAssociationDestination(core, model_id, "instanceOf")
			if (allow_read(current_user_id, type_id)):
				if (read_type(core, type_id) != "Folder"):
					Element mm
					mm = get_full_model(get_entry_id(metamodel_name), get_entry_id("formalisms/SimpleClassDiagrams"))
					if (element_eq(mm, read_root())):
						return "Type cannot be typed as formalisms/SimpleClassDiagrams: " + metamodel_name!

					output("Waiting for model constructors...")
					new_model = compile_model(input(), mm)

					if (is_physical_string(new_model)):
						return "Compilation error: " + cast_string(new_model)!

					model_overwrite(new_model, model_id, get_entry_id(metamodel_name))
					return "Success"!
				else:
					return "Not a model: " + full_name(type_id)!
			else:
				return "Read permission denied to: " + full_name(type_id)!
		else:
			return "Write permission denied to: " + model_name!
	else:
		return "Model not found: " + model_name!

String function cmd_model_modify(model_name : String, metamodel_name : String):
	// Model modify operation, which uses the mini_modify.alc operations, though with extensions for access control
	String model_id
	String type_id

	model_id = get_entry_id(model_name)

	if (model_id != ""):
		if (allow_read(current_user_id, model_id)):
			type_id = get_entry_id(metamodel_name)
			if (type_id != ""):
				if (allow_read(current_user_id, type_id)):
					if (read_type(core, model_id) != "Folder"):
						if (read_type(core, type_id) != "Folder"):
							Element new_model
							new_model = get_full_model(model_id, type_id)
							if (element_eq(new_model, read_root())):
								return "Conformance hierarchy unknown for: " + model_name!
							modify(new_model, allow_write(current_user_id, model_id))
							if (allow_write(current_user_id, model_id)):
								// Overwrite the modified model
								model_overwrite(new_model, model_id, type_id)
							return "Success"!
						else:
							return "Not a model: " + metamodel_name!
					else:
						return "Not a model: " + model_name!
				else:
					return "Read permission denied to: " + metamodel_name!
			else:
				return "Model not found: " + metamodel_name!
		else:
			return "Read permission denied to: " + model_name!
	else:
		return "Model not found: " + model_name!

Void function model_delete(model_id : String):
	if (read_type(core, model_id) == "Folder"):
		// Folder, so delete all containing elements as well!
		Element elems
		elems = allAssociationDestinations(core, model_id, "contains")
		while (set_len(elems) > 0):
			model_delete(set_pop(elems))

		// Delete self
		model_delete_element(core, model_id)
	else:
		// Only delete this element
		model_delete_element(core, model_id)
	
	return!

String function cmd_model_delete(model_name : String):
	String model_id
	model_id = get_entry_id(model_name)

	if (model_id != ""):
		if (allow_write(current_user_id, model_id)):
			model_delete(model_id)
			return "Success"!
		else:
			return "Write permission denied to: " + model_name!
	else:
		return "Model not found: " + model_name!

String function cmd_read_permissions(location : String):
	if (get_entry_id(location) != ""):
		String result
		result = "Success: "
		if (allow_read(current_user_id, get_entry_id(location))):
			result = result + "R"
		if (allow_write(current_user_id, get_entry_id(location))):
			result = result + "W"
		return result!
	else:
		return "Unknown location: " + location!

String function cmd_model_list(location : String):
	// List all models
	if (get_entry_id(location) != ""):
		if (allow_read(current_user_id, get_entry_id(location))):
			Element models
			String result
			String m

			result = "Success: "
			models = allAssociationDestinations(core, get_entry_id(location), "contains")
			while (set_len(models) > 0):
				m = set_pop(models)
				if (is_nominal_instance(core, m, "Folder")):
					result = result + (get_filename(read_attribute(core, m, "name")) + "/\n")
				else:
					result = result + (get_filename(read_attribute(core, m, "name")) + "\n")
			return result!
		else:
			return "Read permission denied to: " + location!
	else:
		return "Unknown location: " + location!

String function cmd_model_list_full(location : String):
	// List all models with full info
	if (get_entry_id(location) != ""):
		if (allow_read(current_user_id, get_entry_id(location))):
			Element models
			String m
			String permissions
			String owner
			String group
			String name
			String type
			String result

			result = "Success: "
			models = allAssociationDestinations(core, get_entry_id(location), "contains")
			while (set_len(models) > 0):
				m = set_pop(models)
				permissions = read_attribute(core, m, "permissions")
				owner = read_attribute(core, anAssociationDestination(core, m, "owner"), "name")
				group = read_attribute(core, anAssociationDestination(core, m, "group"), "name")
				if (is_nominal_instance(core, m, "Folder")):
					name = get_filename(read_attribute(core, m, "name")) + "/"
				else:
					name = get_filename(read_attribute(core, m, "name"))
				result = result + permissions + " " + owner + " " + group + " " + name + "\n"
			return result!
		else:
			return "Read permission denied to: " + location!
	else:
		return "Unknown location: " + location!

String function cmd_transformation_add_MANUAL(source_models : Element, target_models : Element, operation_name : String):
	return transformation_add(source_models, target_models, operation_name, "manual")!

String function cmd_transformation_add_AL(source_models : Element, target_models : Element, operation_name : String):
	return transformation_add(source_models, target_models, operation_name, "actionlanguage")!

String function transformation_add(source_models : Element, target_models : Element, operation_name : String, operation_type : String):
	// Add a manual transformation model
	String model_id
	Element models
	Element source
	Element target
	String name
	Element all_formalisms
	Element formalism_map
	Element merged_formalism
	String merged_formalism_id
	String source_formalism_id
	String tracability_link
	Element fused
	Element keys
	String key
	Element mm

	source = dict_create()
	target = dict_create()
	all_formalisms = set_create()
	formalism_map = set_create()
	fused = set_create()

	keys = dict_keys(source_models)
	while (set_len(keys) > 0):
		key = set_pop(keys)
		name = source_models[key]
		model_id = get_entry_id(name)
		if (model_id != ""):
			if (allow_read(current_user_id, model_id)):
				if (bool_not(dict_in(source, key))):
					dict_add(source, key, model_id)

					if (read_type(core, model_id) == "Folder"):
						return "Not a model: " + name!

					mm = get_full_model(model_id, get_entry_id("formalisms/SimpleClassDiagrams"))
					if (element_eq(mm, read_root())):
						return "Type cannot be typed as formalisms/SimpleClassDiagrams: " + key!

					if (bool_not(set_in(fused, key))):
						set_add_node(formalism_map, create_tuple(key, mm))
						set_add(fused, key)

					if (bool_not(set_in(all_formalisms, model_id))):
						set_add(all_formalisms, model_id)
				else:
					return "Name already selected for source: " + key!
			else:
				return "Read permission denied to: " + name!
		else:
			return "Model not found: " + name!

	keys = dict_keys(target_models)
	while (set_len(keys) > 0):
		key = set_pop(keys)
		name = target_models[key]
		model_id = get_entry_id(name)
		if (model_id != ""):
			if (allow_read(current_user_id, model_id)):
				if (bool_not(dict_in(target, key))):
					if (read_type(core, model_id) == "Folder"):
						return "Not a model: " + name!

					if (dict_in(source, key)):
						if (value_neq(source[key], model_id)):
							return "Input and output signature differ for same key: " + key!

					dict_add(target, key, model_id)
					mm = get_full_model(model_id, get_entry_id("formalisms/SimpleClassDiagrams"))
					if (element_eq(mm, read_root())):
						return "Type cannot be typed as formalisms/SimpleClassDiagrams: " + key!

					if (bool_not(set_in(fused, key))):
						set_add_node(formalism_map, create_tuple(key, mm))
						set_add(fused, key)

					if (bool_not(set_in(all_formalisms, model_id))):
						set_add(all_formalisms, model_id)
				else:
					return "Name already selected for target: " + key!
			else:
				return "Read permission denied to: " + name!
		else:
			return "Model not found: " + name!

	if (get_entry_id(operation_name) == ""):
		// Write out a merged metamodel containing all these models: this is the MM for the manual operation
		// New location is available, so write
		if (dict_len(source_models) + dict_len(target_models) > 0):
			merged_formalism = model_fuse(formalism_map)
			model_create(merged_formalism, "merged/" + operation_name, get_entry_id("formalisms/SimpleClassDiagrams"), "Model")
			do_spawn_modify("merged/" + operation_name, True)
			merged_formalism = get_full_model(get_entry_id("merged/" + operation_name), get_entry_id("formalisms/SimpleClassDiagrams"))

		if (operation_type == "manual"):
			// Finished with all information, now create the model itself!
			Element m
			m = get_full_model(get_entry_id("formalisms/ManualOperation"), get_entry_id("formalisms/SimpleClassDiagrams"))
			model_create(instantiate_model(m), operation_name, get_entry_id("formalisms/ManualOperation"), "ManualOperation")
			model_id = get_entry_id(operation_name)

		elif (operation_type == "actionlanguage"):
			// Finished with all information, now create the model itself!
			output("Waiting for code constructors...")
			Element compiled
			compiled = compile_code(input())
			if (is_physical_string(compiled)):
				return "Compilation error: " + cast_string(compiled)!

			model_create(compiled, operation_name, get_entry_id("formalisms/ActionLanguage"), "ActionLanguage")
			model_id = get_entry_id(operation_name)

		if (dict_len(source_models) + dict_len(target_models) > 0):
			merged_formalism_id = get_entry_id("merged/" + operation_name)

			// Add tracability links at this level
			while (set_len(all_formalisms) > 0):
				source_formalism_id = set_pop(all_formalisms)
				tracability_link = instantiate_link(core, "tracability", "", merged_formalism_id, source_formalism_id)
				instantiate_attribute(core, tracability_link, "type", "merged")

			tracability_link = instantiate_link(core, "tracability", "", model_id, merged_formalism_id)
			instantiate_attribute(core, tracability_link, "type", "operatesOn")

			// Extend metadata with info on source and target
			String link
			String dst

			keys = dict_keys(source)
			while (set_len(keys) > 0):
				key = set_pop(keys)
				link = instantiate_link(core, "transformInput", "", model_id, source[key])
				instantiate_attribute(core, link, "name", key)

			keys = dict_keys(target)
			while (set_len(keys) > 0):
				key = set_pop(keys)
				link = instantiate_link(core, "transformOutput", "", model_id, target[key])
				instantiate_attribute(core, link, "name", key)
			
		return "Success"!
	else:
		return "Model exists: " + operation_name!

String function cmd_transformation_add_MT(source_models : Element, target_models : Element, operation_name : String):
	// Add a model transformation model
	// Just a usual model instantiation, but need to add the source and target links based on user info
	String ramified_metamodel_id
	Element ramified_metamodel
	String model_id
	Element models
	Element links
	String link_id
	Element supported
	Element source
	Element target
	String name
	String new_model_id
	String merged_link_id
	Element links_merged
	String merged_formalism
	Element keys
	String key
	Element mm
	Element to_ramify
	String source_formalism_id
	String merged_formalism_id
	String tracability_link

	source = dict_create()
	target = dict_create()
	to_ramify = set_create()

	if (dict_len(source_models) + dict_len(target_models) == 0):
		return "Model transformation needs at least one formalism in its input or output signature!"!

	keys = dict_keys(source_models)
	while (set_len(keys) > 0):
		key = set_pop(keys)
		name = source_models[key]
		model_id = get_entry_id(name)
		if (model_id != ""):
			if (allow_read(current_user_id, model_id)):
				// Check whether or not it is formalisms/SimpleClassDiagrams
				if (read_type(core, model_id) == "Folder"):
					return "Not a model: " + name!

				mm = get_full_model(model_id, get_entry_id("formalisms/SimpleClassDiagrams"))
				if (element_neq(mm, read_root())):
					if (bool_not(dict_in(source, key))):
						dict_add(source, key, model_id)
						set_add_node(to_ramify, create_tuple(key, mm))
					else:
						return "Name was already assigned a metamodel: " + key!
				else:
					return "Type cannot be typed as formalisms/SimpleClassDiagrams: " + name!
			else:
				return "Read permission denied to: " + name!
		else:
			return "Model not found: " + name!

	keys = dict_keys(target_models)
	while (set_len(keys) > 0):
		key = set_pop(keys)
		name = target_models[key]
		model_id = get_entry_id(name)
		if (model_id != ""):
			if (allow_read(current_user_id, model_id)):
				if (read_type(core, model_id) == "Folder"):
					return "Not a model: " + name!

				mm = get_full_model(model_id, get_entry_id("formalisms/SimpleClassDiagrams"))
				if (element_neq(mm, read_root())):
					if (bool_not(dict_in(target, key))):
						if (dict_in(source, key)):
							if (value_eq(model_id, source[key])):
								dict_add(target, key, model_id)
								// Don't add to to_ramify, as it is already in there!
							else:
								return "Input and output signature differ for same key: " + key!
						else:
							dict_add(target, key, model_id)
							set_add_node(to_ramify, create_tuple(key, mm))
					else:
						return "Name was already assigned a metamodel: " + key!
				else:
					return "Type cannot be typed as formalisms/SimpleClassDiagrams: " + name!
			else:
				return "Read permission denied to: " + name!
		else:
			return "Model not found: " + name!

	merged_formalism = model_fuse(to_ramify)
	model_create(merged_formalism, "merged/" + operation_name, get_entry_id("formalisms/SimpleClassDiagrams"), "Model")
	do_spawn_modify("merged/" + operation_name, True)
	merged_formalism = get_full_model(get_entry_id("merged/" + operation_name), get_entry_id("formalisms/SimpleClassDiagrams"))
	model_overwrite(merged_formalism, get_entry_id("merged/" + operation_name), get_entry_id("formalisms/SimpleClassDiagrams"))

	ramified_metamodel = ramify(merged_formalism)
	model_create(ramified_metamodel, "RAMified/" + operation_name, get_entry_id("formalisms/SimpleClassDiagrams"), "Model")
	ramified_metamodel_id = get_entry_id("RAMified/" + operation_name)
	
	// Now use the RAMified model to create the instance
	if (get_entry_id(operation_name) == ""):
		String new_model
		// Finished with all information, now create the model itself!
		output("Waiting for model constructors...")
		new_model = compile_model(input(), get_full_model(ramified_metamodel_id, get_entry_id("formalisms/SimpleClassDiagrams")))
		if (is_physical_string(new_model)):
			return "Compilation error: " + cast_string(new_model)!
		model_create(new_model, operation_name, ramified_metamodel_id, "ModelTransformation")
		model_id = get_entry_id(operation_name)

		// Write out a merged metamodel containing all these models: this is the MM for the manual operation
		// New location is available, so write
		model_create(merged_formalism, "merged/" + operation_name, get_entry_id("formalisms/SimpleClassDiagrams"), "Model")
		merged_formalism_id = get_entry_id("merged/" + operation_name)

		// Add tracability links at this level
		tracability_link = instantiate_link(core, "tracability", "", model_id, merged_formalism_id)
		instantiate_attribute(core, tracability_link, "type", "operatesOn")

		// Add tracability links at this level
		tracability_link = instantiate_link(core, "tracability", "", merged_formalism_id, ramified_metamodel_id)
		instantiate_attribute(core, tracability_link, "type", "RAMified")

		// Extend metadata with info on source and target
		String link
		String dst

		keys = dict_keys(source)
		while (set_len(keys) > 0):
			key = set_pop(keys)
			dst = source[key]
			link = instantiate_link(core, "transformInput", "", model_id, dst)
			instantiate_attribute(core, link, "name", key)

		keys = dict_keys(target)
		while (set_len(keys) > 0):
			key = set_pop(keys)
			dst = target[key]
			link = instantiate_link(core, "transformOutput", "", model_id, dst)
			instantiate_attribute(core, link, "name", key)

		return "Success"!
	else:
		return "Model exists: " + operation_name!

String function cmd_permission_modify(model_name : String, permissions : String):
	Integer permission
	String model_id

	model_id = get_entry_id(model_name)
	if (model_id != ""):
		if (get_relation_to_model(current_user_id, model_id) == 0):
			Boolean fail
			Integer i
			i = 0
			fail = False

			if (string_len(permissions) != 3):
				fail = True

			while (i < 3):
				permission = cast_integer(string_get(permissions, i))
				if (bool_or(permission < 0, permission > 2)):
					fail = True
					break!
				i = i + 1

			if (bool_not(fail)):
				unset_attribute(core, model_id, "permissions")
				instantiate_attribute(core, model_id, "permissions", permissions)
				return "Success"!
			else:
				return "Incorrect format: must be a string of three characters, with each character being a digit between 0 and 2"!
		else:
			return "User permission denied to: " + model_name!
	else:
		return "Model not found: " + model_name!

String function cmd_permission_owner(model_name : String, new_user_name : String):
	String model_id
	String new_user_id

	model_id = get_entry_id(model_name)
	if (model_id != ""):
		if (bool_or(get_relation_to_model(current_user_id, model_id) == 0, is_admin(current_user_id))):
			new_user_id = get_user_id(new_user_name)
			if (new_user_id != ""):
				model_delete_element(core, set_pop(allOutgoingAssociationInstances(core, model_id, "owner")))
				instantiate_link(core, "owner", "", model_id, new_user_id)
				return "Success"!
			else:
				return "Unknown user: " + new_user_name!
		else:
			return "User permission denied to: " + model_name!
	else:
		return "Model not found: " + model_name!

String function cmd_permission_group(model_name : String, new_group_name : String):
	String model_id
	String group_id

	model_id = get_entry_id(model_name)
	if (model_id != ""):
		if (bool_or(get_relation_to_model(current_user_id, model_id) == 0, is_admin(current_user_id))):
			group_id = get_group_id(new_group_name)
			if (group_id != ""):
				model_delete_element(core, set_pop(allOutgoingAssociationInstances(core, model_id, "group")))
				instantiate_link(core, "group", "", model_id, group_id)
				return "Success"!
			else:
				return "Unknown group: " + new_group_name!
		else:
			return "User permission denied to: " + model_name!
	else:
		return "Model not found: " + model_name!

String function cmd_group_create(group_name : String):
	// Create a new group and become its owner
	String group_id
	String name

	group_id = get_group_id(group_name)
	if (group_id == ""):
		group_id = instantiate_node(core, "Group", "")
		instantiate_attribute(core, group_id, "name", group_name)
		instantiate_link(core, "belongsTo", "", current_user_id, group_id)
		instantiate_link(core, "owner", "", group_id, current_user_id)
		return "Success"!
	else:
		return "Group exists: " + group_name!

String function cmd_group_delete(group_name : String):
	// Delete an existing group
	String group_id

	group_id = get_group_id(group_name)
	if (group_id != ""):
		if (allow_group_modify(current_user_id, group_id)):
			model_delete_element(core, group_id)
			return "Success"!
		else:
			return "Group permission denied to: " + group_name!
	else:
		return "Unknown group: " + group_name!

String function cmd_group_owner_add(group_name : String, other_user_name : String):
	// Add an owner to your group
	String group_id
	String other_user_id

	group_id = get_group_id(group_name)
	if (group_id != ""):
		if (allow_group_modify(current_user_id, group_id)):
			other_user_id = get_user_id(other_user_name)
			if (other_user_id != ""):
				if (bool_not(set_in(allAssociationDestinations(core, group_id, "owner"), other_user_id))):
					instantiate_link(core, "owner", "", group_id, other_user_id)

					if (bool_not(set_in(allAssociationDestinations(core, other_user_id, "belongsTo"), group_id))):
						instantiate_link(core, "belongsTo", "", other_user_id, group_id)

					return "Success"!
				else:
					return "Success"!
			else:
				return "Unknown user: " + other_user_name!
		else:
			return "Group permission denied to: " + group_name!
	else:
		return "Unknown group: " + group_name!

String function cmd_group_owner_delete(group_name : String, other_user_name : String):
	// Remove an owner from your group
	String group_id
	String other_user_id

	group_id = get_group_id(group_name)
	if (group_id != ""):
		if (allow_group_modify(current_user_id, group_id)):
			other_user_id = get_user_id(other_user_name)
			if (other_user_id != ""):
				if (set_in(allAssociationDestinations(core, other_user_id, "belongsTo"), group_id)):
					if (set_in(allAssociationDestinations(core, group_id, "owner"), other_user_id)):
						Element overlap
						overlap = set_overlap(allIncomingAssociationInstances(core, other_user_id, "owner"), allOutgoingAssociationInstances(core, group_id, "owner"))
						model_delete_element(core, set_pop(overlap))
						return "Success"!
					else:
						return "Success"!
				else:
					return "User is not a member of the group!"!
			else:
				return "Unknown user: " + other_user_name!
		else:
			return "Group permission denied to: " + group_name!
	else:
		return "Unknown group: " + group_name!

String function cmd_group_join(group_name : String, other_user_name : String):
	// Add someone to your group
	String group_id
	String other_user_id

	group_id = get_group_id(group_name)
	if (group_id != ""):
		if (allow_group_modify(current_user_id, group_id)):
			other_user_id = get_user_id(other_user_name)
			if (other_user_id != ""):
				if (bool_not(set_in(allAssociationDestinations(core, other_user_id, "belongsTo"), group_id))):
					instantiate_link(core, "belongsTo", "", other_user_id, group_id)
					return "Success"!
				else:
					return "User exists: " + other_user_name!
			else:
				return "Unknown user: " + other_user_name!
		else:
			return "Group permission denied to: " + group_name!
	else:
		return "Unknown group: " + group_name!

String function cmd_group_kick(group_name : String, other_user_name : String):
	// Remove someone from your group
	String group_id
	String other_user_id

	group_id = get_group_id(group_name)
	if (group_id != ""):
		if (allow_group_modify(current_user_id, group_id)):
			other_user_id = get_user_id(other_user_name)
			if (other_user_id != ""):
				Element overlap
				if (set_in(allAssociationDestinations(core, other_user_id, "belongsTo"), group_id)):
					overlap = set_overlap(allIncomingAssociationInstances(core, group_id, "belongsTo"), allOutgoingAssociationInstances(core, other_user_id, "belongsTo"))
					model_delete_element(core,set_pop(overlap))

					// Check if user was an owner as well
					if (set_in(allAssociationDestinations(core, group_id, "owner"), other_user_id)):
						overlap = set_overlap(allIncomingAssociationInstances(core, other_user_id, "owner"), allOutgoingAssociationInstances(core, group_id, "owner"))
						model_delete_element(core, set_pop(overlap))

					return "Success"!
				else:
					return "User is not a member of the group!"!
			else:
				return "Unknown user: " + other_user_name!
		else:
			return "Group permission denied to: " + group_name!
	else:
		return "Unknown group: " + group_name!

String function cmd_group_list():
	// List all groups you are a member of (and whether you are admin or not!)
	Element groups
	String group_id
	String admin
	String result
	
	result = "Success: "
	groups = allAssociationDestinations(core, current_user_id, "belongsTo")
	while (set_len(groups) > 0):
		group_id = set_pop(groups)
		if (set_in(allAssociationDestinations(core, group_id, "owner"), current_user_id)):
			admin = " A "
		else:
			admin = "   "

		result = result + (string_join(admin, read_attribute(core, group_id, "name")) + "\n")

	return result!

String function cmd_admin_promote(other_user_name : String):
	// Promote a user to admin status
	if (is_admin(current_user_id)):
		String other_user_id

		other_user_id = get_user_id(other_user_name)
		if (other_user_id != ""):
			unset_attribute(core, other_user_id, "admin")
			instantiate_attribute(core, other_user_id, "admin", True)
			return "Success"!
		else:
			return "Unknown user: " + other_user_name!
	else:
		return "Admin permission denied"!

String function cmd_admin_demote(other_user_name : String):
	// Demote a user to normal status
	if (is_admin(current_user_id)):
		String other_user_id

		other_user_id = get_user_id(other_user_name)
		if (other_user_id != ""):
			unset_attribute(core, other_user_id, "admin")
			instantiate_attribute(core, other_user_id, "admin", False)
			return "Success"!
		else:
			return "Unknown user: " + other_user_name!
	else:
		return "Admin permission denied"!

String function cmd_service_register(service_name : String):
	// Active a service for this specific user
	if (get_service_id(service_name) == ""):
		String service
		service = instantiate_node(core, "Service", "")
		instantiate_attribute(core, service, "name", service_name)
		instantiate_attribute(core, service, "port", get_taskname())
		output("Success: " + get_taskname())

		// Wait until we can stop the service
		while (cast_value(input()) != "\"service_stop\""):
			output("Service is running on this task: stop it by sending 'service_stop'")

		model_delete_element(core, service)

		// Service terminated
		return "Success"!
	else:
		return "Service already exists: " + service_name!

String function cmd_user_password(user_name : String, new_password : String):
	if (bool_or(current_user_id == get_user_id(user_name), is_admin(current_user_id))):
		if (get_user_id(user_name) != ""):
			instantiate_attribute(core, get_user_id(user_name), "password", hash(new_password))
			return "Success"!
		else:
			return "Unknown user: " + user_name!
	else:
		return "User permission denied to: " + user_name!

String function cmd_transformation_signature(transformation_name : String):
	String model_id
	model_id = get_entry_id(transformation_name)

	if (model_id != ""):
		if (allow_execute(current_user_id, model_id)):
			if (is_nominal_instance(core, model_id, "Transformation")):
				String result
				String elem
				Element inputs
				Element outputs

				result = "Success: "
				inputs = allOutgoingAssociationInstances(core, model_id, "transformInput")
				while (set_len(inputs) > 0):
					elem = set_pop(inputs)
					result = string_join(string_join(string_join(string_join(result + "I ", read_attribute(core, elem, "name")), " "), full_name(readAssociationDestination(core, elem))), "\n")

				outputs = allOutgoingAssociationInstances(core, model_id, "transformOutput")
				while (set_len(outputs) > 0):
					elem = set_pop(outputs)
					result = string_join(string_join(string_join(string_join(result + "O ", read_attribute(core, elem, "name")), " "), full_name(readAssociationDestination(core, elem))), "\n")

				return result!
			else:
				return "Model is not an operation: " + transformation_name!
		else:
			return "Execute permission denied to: " + transformation_name!
	else:
		return "Model not found: " + transformation_name!

String function cmd_model_types(model_name : String):
	if (get_entry_id(model_name) != ""):
		String model_id
		model_id = get_entry_id(model_name)

		Element types
		String type_link
		String result

		result = "Success: "
		if (read_type(core, model_id) != "Folder"):
			types = allOutgoingAssociationInstances(core, model_id, "instanceOf")
			while (set_len(types) > 0):
				type_link = set_pop(types)
				result = result + cast_string(full_name(readAssociationDestination(core, type_link))) + ", " + cast_string(full_name(anAssociationDestination(core, type_link, "typing"))) + ", None\n"

			return result!
		else:
			return "Not a model: " + model_name!
	else:
		return "Model not found: " + model_name!
	
String function cmd_folder_create(folder_name : String):
	if (get_entry_id(folder_name) == ""):
		if (element_neq(create_folders(current_user_id, folder_name), read_root())):
			return "Success"!
		else:
			return "Write permission denied to: " + folder_name!
	else:
		return "Folder exists: " + folder_name!

String function cmd_conformance_delete(model_name : String, metamodel_name : String, typemapping_name : String):
	// Remove an existing instanceOf relation
	if (get_entry_id(model_name) != ""):
		if (get_entry_id(metamodel_name) != ""):
			if (bool_not(read_type(core, get_entry_id(model_name)) == "Folder")):
				if (bool_not(read_type(core, get_entry_id(metamodel_name)) == "Folder")):
					Element links
					String link
					String found_typing_name
					Element typings

					links = get_instanceOf_links(get_entry_id(model_name), get_entry_id(metamodel_name))
					while (set_len(links) > 0):
						// Iterate over each link and remove if type mapping matches
						link = set_pop(links)
						typings = allAssociationDestinations(core, link, "typing")
						if (set_len(typings) > 0):
							found_typing_name = set_pop(typings)
						else:
							found_typing_name = ""

						if (bool_and(typemapping_name == "", found_typing_name == "")):
							// Remove only the link
							model_delete_element(core, link)
						elif found_typing_name == "":
							continue!
						else:
							found_typing_name = read_attribute(core, found_typing_name, "name")
							if (found_typing_name == typemapping_name):
								// Type mappings match, so remove link
								// Optional: type mapping model can also be removed, but is potentially in use as it is itself a model!
								model_delete_element(core, link)
					return "Success"!
				else:
					return "Not a model: " + metamodel_name!
			else:
				return "Not a model: " + model_name!
		else:
			return "Model not found: " + metamodel_name!
	else:
		return "Model not found: " + model_name!

String function cmd_conformance_add(model_name : String, metamodel_name : String):
	// Create a new instanceOf relation now
	if (get_entry_id(model_name) != ""):
		if (get_entry_id(metamodel_name) != ""):
			if (bool_not(read_type(core, get_entry_id(model_name)) == "Folder")):
				if (bool_not(read_type(core, get_entry_id(metamodel_name)) == "Folder")):
					instantiate_link(core, "instanceOf", "", get_entry_id(model_name), get_entry_id(metamodel_name))
				else:
					return "Not a model: " + metamodel_name!
			else:
				return "Not a model: " + model_name!
		else:
			return "Model not found: " + metamodel_name!
	else:
		return "Model not found: " + model_name!
	return "Success"!

Void function new_task():
	String username
	String user_id
	String password

	// Load in a hard-reference to the previously created model
	core = import_node(core_model_location)

	caches = dict_create()
	dict_add_fast(caches, "models", dict_create())
	dict_add_fast(caches, "users", dict_create())
	dict_add_fast(caches, "full_name", dict_create())

	// Find root element
	Element elems
	String elem
	elems = allInstances(core, "Folder")
	while (set_len(elems) > 0):
		elem = set_pop(elems)
		if (value_eq(read_attribute(core, elem, "name"), "")):
			if (set_len(allIncomingAssociationInstances(core, elem, "contains")) == 0):
				dict_add_fast(caches, "root", elem)
				break!

	while (True):
		output("Log on as which user?")
		username = input()

		user_id = get_user_id(username)
		if (user_id == ""):
			// New user
			// Add user to Core Formalism
			user_id = instantiate_node(core, "User", "")
			instantiate_attribute(core, user_id, "name", username)
			instantiate_attribute(core, user_id, "admin", False)

			output("This is a new user: please give password!")
			password = hash(input())

			output("Please repeat the password")
			if (password == hash(input())):
				output("Passwords match!")
				instantiate_attribute(core, user_id, "password", password)

				// Now create a folder for this user's models!
				current_user_id = get_user_id("admin")
				create_folders(user_id, "users/" + username)
				current_user_id = user_id

				// Can continue as we are logged on now!
			else:
				output("Not the same password!")
				continue!
		elif (bool_not(check_login(user_id))):
			output("Wrong password!")
			continue!

		String cmd
		String result

		current_user_id = user_id

		output("Welcome to the Model Management Interface v2.0!")
		output("Use the 'help' command for a list of possible commands")

		while (True):
			cmd = input()
			if (cmd == "help"):
				output(cmd_help())
			elif (cmd == "model_add"):
				output(cmd_model_add(single_input("Model type?"), single_input("Model name?"), single_input("Model textual representation?")))
			elif (cmd == "model_move"):
				output(cmd_model_move(single_input("Model name?"), single_input("New location?")))
			elif (cmd == "process_execute"):
				output(cmd_process_execute(single_input("Process to execute?"), dict_input("Model bindings to use?")))
			elif (cmd == "process_signature"):
				output(cmd_process_signature(single_input("Process to query?")))
			elif (cmd == "transformation_between"):
				output(cmd_transformation_between(dict_input("Source signature?"), dict_input("Target signature?")))
			elif (cmd == "model_render"):
				output(cmd_model_render(single_input("Model name?"), single_input("Mapper name?"), single_input("Rendered name?")))
			elif (cmd == "model_rendered"):
				output(cmd_model_rendered(single_input("Model name?"), single_input("Mapper name?")))
			elif (cmd == "transformation_execute"):
				output(cmd_transformation_execute(single_input("Transformation name?"), dict_input("Source models?"), dict_input("Target models?"), single_input("Tracability model?")))
			elif (cmd == "verify"):
				result = cmd_verify(single_input("Model name?"), single_input("Metamodel name?"))
				if (result != ""):
					output(result)
			elif (cmd == "model_overwrite"):
				output(cmd_model_overwrite(single_input("Model name?"), single_input("Metamodel name?")))
			elif (cmd == "model_modify"):
				output(cmd_model_modify(single_input("Model name?"), single_input("Metamodel name?")))
			elif (cmd == "model_delete"):
				output(cmd_model_delete(single_input("Model name?")))
			elif (cmd == "model_list"):
				output(cmd_model_list(single_input("Location?")))
			elif (cmd == "model_list_full"):
				output(cmd_model_list_full(single_input("Location?")))
			elif (cmd == "read_permissions"):
				output(cmd_read_permissions(single_input("Location?")))
			elif (cmd == "transformation_add_MANUAL"):
				output(cmd_transformation_add_MANUAL(dict_input("Source models?"), dict_input("Target models?"), single_input("Operation name?")))
			elif (cmd == "transformation_add_AL"):
				output(cmd_transformation_add_AL(dict_input("Source models?"), dict_input("Target models?"), single_input("Operation name?")))
			elif (cmd == "transformation_add_MT"):
				output(cmd_transformation_add_MT(dict_input("Source models?"), dict_input("Target models?"), single_input("Operation name?")))
			elif (cmd == "permission_modify"):
				output(cmd_permission_modify(single_input("Model name?"), single_input("Permissions?")))
			elif (cmd == "permission_owner"):
				output(cmd_permission_owner(single_input("Model name?"), single_input("New owning user?")))
			elif (cmd == "permission_group"):
				output(cmd_permission_group(single_input("Model name?"), single_input("New owning group?")))
			elif (cmd == "group_create"):
				output(cmd_group_create(single_input("New group name?")))
			elif (cmd == "group_delete"):
				output(cmd_group_delete(single_input("Group name?")))
			elif (cmd == "group_owner_add"):
				output(cmd_group_owner_add(single_input("Group name?"), single_input("User name?")))
			elif (cmd == "group_owner_delete"):
				output(cmd_group_owner_delete(single_input("Group name?"), single_input("User name?")))
			elif (cmd == "group_join"):
				output(cmd_group_join(single_input("Group name?"), single_input("User name?")))
			elif (cmd == "group_kick"):
				output(cmd_group_kick(single_input("Group name?"), single_input("User name?")))
			elif (cmd == "group_list"):
				output(cmd_group_list())
			elif (cmd == "admin_promote"):
				output(cmd_admin_promote(single_input("User name?")))
			elif (cmd == "admin_demote"):
				output(cmd_admin_demote(single_input("User name?")))
			elif (cmd == "service_register"):
				output(cmd_service_register(single_input("Service name?")))
			elif (cmd == "user_password"):
				output(cmd_user_password(single_input("User name?"), single_input("New password?")))
			elif (cmd == "transformation_read_signature"):
				output(cmd_transformation_signature(single_input("Transformation name?")))
			elif (cmd == "verbose"):
				set_verbose(True)
			elif (cmd == "quiet"):
				set_verbose(False)
			elif (cmd == "user_logout"):
				output("Success")
				break!
			elif (cmd == "exit"):
				output("Success")
				sleep(5)
				return !
			elif (cmd == "folder_create"):
				output(cmd_folder_create(single_input("Folder name?")))
			elif (cmd == "add_conformance"):
				output(cmd_conformance_add(single_input("Model name?"), single_input("Metamodel name?")))
			elif (cmd == "remove_conformance"):
				output(cmd_conformance_delete(single_input("Model name?"), single_input("Metamodel name?"), single_input("Type mapping name?")))
			elif (cmd == "service_poll"):
				// TODO
				cmd = "FAIL"
			elif (cmd == "model_types"):
				output(cmd_model_types(single_input("Model name?")))
			elif (cmd == "AL_text"):
				output(cmd_AL_text(single_input("Code location?")))
			else:
				output("Unknown command: " + cmd)

	// We never get here!
	return !