Add example of 'woods' operational semantics. Clearer error messages. Implement full OD-API. Small refactoring of Conformance class.

api/cd.py

@@ -0,0 +1,92 @@
+from services.bottom.V0 import Bottom
+from uuid import UUID
+
+class CDAPI:
+    def __init__(self, state, m: UUID):
+        self.state = state
+        self.bottom = Bottom(state)
+        self.m = m
+        self.mm = UUID(state.read_value(state.read_dict(state.read_root(), "SCD")))
+
+        # pre-compute some things
+
+        # element -> name
+        self.type_model_names = {
+            self.bottom.read_outgoing_elements(self.m, e)[0]
+                : e for e in self.bottom.read_keys(self.m)
+        }
+
+
+        inh_type, = self.bottom.read_outgoing_elements(self.mm, "Inheritance")
+        inh_links = []
+        for tm_element, tm_name in self.type_model_names.items():
+            types = self.bottom.read_outgoing_elements(tm_element, "Morphism")
+            if inh_type in types:
+                inh_links.append(tm_element)
+
+        # for each inheritance link we add the parent and child to the sub types map
+        # name -> name
+        self.direct_sub_types = { type_name: set() for type_name in self.bottom.read_keys(self.m) } # empty initially
+        self.direct_super_types = { type_name: set() for type_name in self.bottom.read_keys(self.m) } # empty initially
+        for link in inh_links:
+            tm_source = self.bottom.read_edge_source(link)
+            tm_target = self.bottom.read_edge_target(link)
+            parent_name = self.type_model_names[tm_target]
+            child_name = self.type_model_names[tm_source]
+            self.direct_sub_types[parent_name].add(child_name)
+            self.direct_super_types[child_name].add(parent_name)
+
+        def get_transitive_sub_types(type_name: str):
+            # includes the type itself - reason: if we want to get all the instances of some type and its subtypes, we don't have to consider the type itself as an extra case
+            return [type_name, *(sub_type for child_name in self.direct_sub_types.get(type_name, set()) for sub_type in get_transitive_sub_types(child_name) )]
+
+        def get_transitive_super_types(type_name: str):
+            # includes the type itself - reason: if we want to check if something is an instance of a type, we check if its type or one of its super types is equal to the type we're looking for, without having to consider the instance's type itself as an extra case
+            return [type_name, *(super_type for parent_name in self.direct_super_types.get(type_name, set()) for super_type in get_transitive_super_types(parent_name))]
+
+
+        self.transitive_sub_types = { type_name: set(get_transitive_sub_types(type_name)) for type_name in self.direct_sub_types } 
+        self.transitive_super_types = { type_name: set(get_transitive_super_types(type_name)) for type_name in self.direct_super_types }
+
+    def get_type(type_name: str):
+        return self.bottom.read_outgoing_elements(self.m, type_name)[0]
+
+    def is_direct_subtype(super_type_name: str, sub_type_name: str):
+        return sub_type_name in self.direct_sub_types[super_type]
+
+    def is_direct_supertype(sub_type_name: str, super_type_name: str):
+        return super_type_name in self.direct_super_types[sub_type_name]
+
+    def is_subtype(super_type_name: str, sub_type_name: str):
+        return sub_type_name in self.transitive_sub_types[super_type]
+
+    def is_supertype(sub_type_name: str, super_type_name: str):
+        return super_type_name in self.transitive_super_types[sub_type_name]
+
+    # # The edge connecting an object to the value of a slot must be named `{object_name}_{attr_name}`
+    # def get_attr_link_name(self, class_name, attr_name):
+    #     assoc_name = f"{class_name}_{attr_name}"
+    #     type_edges = self.bottom.read_outgoing_elements(self.m, assoc_name)
+    #     if len(type_edges) == 1:
+    #         return assoc_name
+    #     else:
+    #         # look for attribute in the super-types
+    #         conf = Conformance(self.bottom.state, self.model, self.type_model)
+    #         conf.precompute_sub_types() # only need to know about subtypes
+    #         super_types = [s for s in conf.sub_types if class_name in conf.sub_types[s]]
+    #         for s in super_types:
+    #             assoc_name = f"{s}_{attr_name}"
+    #             if len(self.bottom.read_outgoing_elements(self.type_model, assoc_name)) == 1:
+    #                 return assoc_name
+
+    # Attributes are inherited, so when we instantiate an attribute of a class, the AttributeLink may contain the name of the superclass
+    def find_attribute_type(self, class_name: str, attr_name: str):
+        assoc_name = f"{class_name}_{attr_name}"
+        type_edges = self.bottom.read_outgoing_elements(self.m, assoc_name)
+        if len(type_edges) == 1:
+            return type_edges[0]
+        else:
+            for supertype in self.direct_super_types[class_name]:
+                result = self.find_attribute_type(supertype, attr_name)
+                if result != None:
+                    return result

api/od.py

@@ -0,0 +1,148 @@
+from services import od
+from api import cd
+from services.bottom.V0 import Bottom
+from uuid import UUID
+from typing import Optional
+
+NEXT_ID = 0
+
+# Models map names to elements
+# This builds the inverse mapping, so we can quickly lookup the name of an element
+def build_name_mapping(state, m):
+    mapping = {}
+    bottom = Bottom(state)
+    for name in bottom.read_keys(m):
+        element, = bottom.read_outgoing_elements(m, name)
+        mapping[element] = name
+    return mapping
+
+# Object Diagram API
+# Intended to replace the 'services.od.OD' class eventually
+class ODAPI:
+    def __init__(self, state, m: UUID, mm: UUID):
+        self.state = state
+        self.bottom = Bottom(state)
+        self.m = m
+        self.mm = mm
+        self.od = od.OD(mm, m, state)
+        self.cd = cd.CDAPI(state, mm)
+
+        self.create_boolean_value = self.od.create_boolean_value
+        self.create_integer_value = self.od.create_integer_value
+        self.create_string_value = self.od.create_string_value
+        self.create_actioncode_value = self.od.create_actioncode_value
+
+        self.__recompute_mappings()
+
+    # Called after every change - makes querying faster but modifying slower
+    def __recompute_mappings(self):
+        self.obj_to_name = {**build_name_mapping(self.state, self.m), **build_name_mapping(self.state, self.mm)}
+        # self.obj_to_type = {}
+        self.type_to_objs = { type_name : set() for type_name in self.bottom.read_keys(self.mm)}
+        for m_name in self.bottom.read_keys(self.m):
+            m_element, = self.bottom.read_outgoing_elements(self.m, m_name)
+            tm_element = self.get_type(m_element)
+            tm_name = self.obj_to_name[tm_element]
+            # self.obj_to_type[m_name] = tm_name
+            self.type_to_objs[tm_name].add(m_name)
+
+    def get_value(self, obj: UUID):
+        return od.read_primitive_value(self.bottom, obj, self.mm)[0]
+
+    def get_target(self, link: UUID):
+        return self.bottom.read_edge_target(link)
+
+    def get_source(self, link: UUID):
+        return self.bottom.read_edge_source(link)
+
+    def get_slot(self, obj: UUID, attr_name: str):
+        return self.od.get_slot(obj, attr_name)
+
+    def get_slot_link(self, obj: UUID, attr_name: str):
+        return self.od.get_slot_link(obj, attr_name)
+
+    def get_outgoing(self, obj: UUID, assoc_name: str):
+        return od.find_outgoing_typed_by(self.bottom, src=obj, type_node=self.bottom.read_outgoing_elements(self.mm, assoc_name)[0])
+
+    def get_incoming(self, obj: UUID, assoc_name: str):
+        return od.find_incoming_typed_by(self.bottom, tgt=obj, type_node=self.bottom.read_outgoing_elements(self.mm, assoc_name)[0])
+
+    def get_all_instances(self, type_name: str, include_subtypes=True):
+        obj_names = self.type_to_objs[type_name]
+        return [(obj_name, self.bottom.read_outgoing_elements(self.m, obj_name)[0]) for obj_name in obj_names]
+
+    def get_type(self, obj: UUID):
+        types = self.bottom.read_outgoing_elements(obj, "Morphism")
+        if len(types) != 1:
+            raise Exception(f"Expected obj to have 1 type, instead got {len(types)} types.")
+        return types[0]
+
+    def get_name(self, obj: UUID):
+        return (
+            [name for name in self.bottom.read_keys(self.m) if self.bottom.read_outgoing_elements(self.m, name)[0] == obj] +
+            [name for name in self.bottom.read_keys(self.mm) if self.bottom.read_outgoing_elements(self.mm, name)[0] == obj]
+        )[0]
+        return self.obj_to_name[obj]
+
+    def get(self, name: str):
+        return self.bottom.read_outgoing_elements(self.m, name)[0]
+
+    def get_type_name(self, obj: UUID):
+        return self.get_name(self.get_type(obj))
+
+    def is_instance(obj: UUID, type_name: str, include_subtypes=True):
+        typ = self.cd.get_type(type_name)
+        types = set(typ) if not include_subtypes else self.cd.transitive_subtypes[type_name]
+        for type_of_obj in self.bottom.read_outgoing_elements(obj, "Morphism"):
+            if type_of_obj in types:
+                return True
+        return False
+
+    def delete(self, obj: UUID):
+        self.bottom.delete_element(obj)
+        self.__recompute_mappings()
+
+    def get_slot_value(self, obj: UUID, attr_name: str):
+        return self.get_value(self.get_slot(obj, attr_name))
+
+    def set_slot_value(self, obj: UUID, attr_name: str, new_value: any):
+        obj_name = self.get_name(obj)
+
+        link_name = f"{obj_name}_{attr_name}"
+        target_name = f"{obj_name}.{attr_name}"
+
+        old_slot_link = self.get_slot_link(obj, attr_name)
+        if old_slot_link != None:
+            old_target = self.get_target(old_slot_link)
+            # if old_target != None:
+            self.bottom.delete_element(old_target) # this also deletes the slot-link
+
+        new_target = self.create_primitive_value(target_name, new_value)
+        slot_type = self.cd.find_attribute_type(self.get_type_name(obj), attr_name)
+        new_link = self.od._create_link(link_name, slot_type, obj, new_target)
+        self.__recompute_mappings()
+
+    def create_primitive_value(self, name: str, value: any, is_code=False):
+        if isinstance(value, bool):
+            tgt = self.create_boolean_value(name, value)
+        elif isinstance(value, int):
+            tgt = self.create_integer_value(name, value)
+        elif isinstance(value, str):
+            if is_code:
+                tgt = self.create_actioncode_value(name, value)
+            else:
+                tgt = self.create_string_value(name, value)
+        else:
+            raise Exception("Unimplemented type "+value)
+        self.__recompute_mappings()
+        return tgt
+
+    def create_link(self, link_name: Optional[str], assoc_name: str, src: UUID, tgt: UUID):
+        global NEXT_ID
+        typ, = self.bottom.read_outgoing_elements(self.mm, assoc_name)
+        if link_name == None:
+            link_name = f"__{assoc_name}{NEXT_ID}"
+            NEXT_ID += 1
+        link_id = self.od._create_link(link_name, typ, src, tgt)
+        self.__recompute_mappings()
+        return link_id

concrete_syntax/textual_od/parser.py

@@ -90,16 +90,16 @@ def parse_od(state, m_text, mm):
                 # watch out: in Python, 'bool' is subtype of 'int'
                 #  so we must check for 'bool' first
                 if isinstance(value, bool):
-                    tgt = od.create_boolean_value(value_name, value)
+                    od.create_boolean_value(value_name, value)
                 elif isinstance(value, int):
-                    tgt = od.create_integer_value(value_name, value)
+                    od.create_integer_value(value_name, value)
                 elif isinstance(value, str):
-                    tgt = od.create_string_value(value_name, value)
+                    od.create_string_value(value_name, value)
                 elif isinstance(value, _Code):
-                    tgt = od.create_actioncode_value(value_name, value.code)
+                    od.create_actioncode_value(value_name, value.code)
                 else:
                     raise Exception("Unimplemented type "+value)
-                od.create_slot(attr_name, obj_name, tgt)
+                od.create_slot(attr_name, obj_name, value_name)
 
             return obj_name
 

examples/semantics/operational/woods_pysem.py

@@ -1,11 +1,14 @@
+import functools
+
 from state.devstate import DevState
 from bootstrap.scd import bootstrap_scd
 from framework.conformance import Conformance, render_conformance_check_result
 from concrete_syntax.textual_od import parser, renderer
 from concrete_syntax.common import indent
 from concrete_syntax.plantuml import renderer as plantuml
-from util.prompt import yes_no, pause
+from util import prompt
 from transformation.cloner import clone_od
+from api.od import ODAPI
 
 state = DevState()
 
@@ -86,6 +89,40 @@ woods_rt_mm_cs = woods_mm_cs + """
     }
     :Inheritance (ManState -> AnimalState)
 
+    attacking:Association (AnimalState -> ManState) {
+        # Animal can only attack one Man at a time
+        target_upper_cardinality = 1;
+
+        # Man can only be attacked by one Animal at a time
+        source_upper_cardinality = 1;
+
+        constraint = ```
+            source = get_source(this)
+            if get_type_name(source) == "BearState":
+                # only BearState has 'hunger' attribute
+                hunger = get_value(get_slot(source, "hunger"))
+            else:
+                hunger = 100 # Man can always attack
+            animal_state = get_source(this)
+            animal_dead = get_value(get_slot(animal_state, "dead"))
+            man_state = get_target(this)
+            man_dead = get_value(get_slot(man_state, "dead"))
+            hunger > 50 and not animal_dead and not man_dead # whoever is dead cannot attack or get attacked
+        ```;
+    }
+
+    attacking_starttime:AttributeLink (attacking -> Integer) {
+        name = "starttime";
+        optional = False;
+        constraint = ```
+            val = get_value(get_target(this))
+            _, clock = get_all_instances("Clock")[0]
+            current_time = get_slot_value(clock, "time")
+            val >= 0 and val <= current_time
+        ```;
+    }
+
+    # Just a clock singleton for keeping the time
     Clock:Class {
         lower_cardinality = 1;
         upper_cardinality = 1;
@@ -182,11 +219,106 @@ print("RT-M valid?")
 conf = Conformance(state, woods_rt_m, woods_rt_mm)
 print(render_conformance_check_result(conf.check_nominal()))
 
-# print("--------------")
-# print(indent(
-#     renderer.render_od(state,
-#         m_id=woods_rt_m,
-#         mm_id=woods_rt_mm),
-#     4))
-# print("--------------")
-
+def filter_actions(old_od):
+    result = {}
+    for name, callback in get_actions(old_od).items():
+        # Clone OD before transforming
+        cloned_rt_m = clone_od(state, old_od.m, old_od.mm)
+        new_od = ODAPI(state, cloned_rt_m, old_od.mm)
+
+        print(f"checking '{name}' ...", end='\r')
+
+        msgs = callback(new_od)
+        conf = Conformance(state, new_od.m, new_od.mm)
+        errors = conf.check_nominal()
+        # erase current line:
+        print("                                                  ", end='\r')
+        if len(errors) == 0:
+            # updated RT-M is conform, we have a valid action:
+            yield (name, (new_od, msgs))
+
+def state_of(od, animal):
+    return od.get_source(od.get_incoming(animal, "of")[0])
+
+def animal_of(od, state):
+    return od.get_target(od.get_outgoing(state, "of")[0])
+
+def advance_time(od):
+    msgs = []
+    _, clock = od.get_all_instances("Clock")[0]
+    old_time = od.get_slot_value(clock, "time")
+    new_time = old_time + 1
+    od.set_slot_value(clock, "time", new_time)
+    msgs.append(f"Time is now {new_time}")
+
+    for _, attacking_link in od.get_all_instances("attacking"):
+        man_state = od.get_target(attacking_link)
+        animal_state = od.get_source(attacking_link)
+        if od.get_type_name(animal_state) == "BearState":
+            od.set_slot_value(animal_state, "hunger", max(od.get_slot_value(animal_state, "hunger") - 50, 0))
+        od.set_slot_value(man_state, "dead", True)
+        od.delete(attacking_link)
+        msgs.append(f"{od.get_name(animal_of(od, animal_state))} kills {od.get_name(animal_of(od, man_state))}.")
+
+    for _, bear_state in od.get_all_instances("BearState"):
+        if od.get_slot_value(bear_state, "dead"):
+            continue # bear already dead
+        old_hunger = od.get_slot_value(bear_state, "hunger")
+        new_hunger = min(old_hunger + 5, 100)
+        od.set_slot_value(bear_state, "hunger", new_hunger)
+        bear = od.get_target(od.get_outgoing(bear_state, "of")[0])
+        bear_name = od.get_name(bear)
+        if new_hunger == 100:
+            od.set_slot_value(bear_state, "dead", True)
+            msgs.append(f"Bear {bear_name} dies of hunger.")
+        else:
+            msgs.append(f"Bear {bear_name}'s hunger level is now {new_hunger}.")
+    return msgs
+
+# we must use the names of the objects as parameters, because when cloning, the IDs of objects change!
+def attack(od, animal_name: str, man_name: str):
+    msgs = []
+    animal = od.get(animal_name)
+    man = od.get(man_name)
+    animal_state = state_of(od, animal)
+    man_state = state_of(od, man)
+    attack_link = od.create_link(None, # auto-generate link name
+        "attacking", animal_state, man_state)
+    _, clock = od.get_all_instances("Clock")[0]
+    current_time = od.get_slot_value(clock, "time")
+    od.set_slot_value(attack_link, "starttime", current_time)
+    msgs.append(f"{animal_name} is now attacking {man_name}")
+    return msgs
+
+def get_actions(od):
+    # can always advance time:
+    actions = { "advance time": advance_time }
+
+    # who can attack whom?
+    for _, afraid_link in od.get_all_instances("afraidOf"):
+        man = od.get_source(afraid_link)
+        animal = od.get_target(afraid_link)
+        animal_name = od.get_name(animal)
+        man_name = od.get_name(man)
+        man_state = state_of(od, man)
+        animal_state = state_of(od, animal)
+        actions[f"{animal_name} ({od.get_type_name(animal)}) attacks {man_name} ({od.get_type_name(man)})"] =functools.partial(attack, animal_name=animal_name, man_name=man_name)
+
+    return actions
+
+od = ODAPI(state, woods_rt_m, woods_rt_mm)
+
+while True:
+    print("--------------")
+    print(indent(
+        renderer.render_od(state,
+            m_id=od.m,
+            mm_id=od.mm),
+        4))
+    print("--------------")
+
+    (od, msgs) = prompt.choose("Select action:", filter_actions(od))
+    print(indent('\n'.join(msgs), 4))
+    if od == None:
+        print("No enabled actions. Quit.")
+        break # no more enabled actions

framework/conformance.py

@@ -6,6 +6,9 @@ from state.base import State
 from typing import Dict, Tuple, Set, Any, List
 from pprint import pprint
 
+from api.cd import CDAPI
+from api.od import ODAPI
+
 import functools
 
 
@@ -21,10 +24,10 @@ def exec_then_eval(code, _globals, _locals):
 
 def render_conformance_check_result(error_list):
     if len(error_list) == 0:
-        return "OK"
+        return "CONFORM"
     else:
         joined = '\n  '.join(error_list)
-        return f"There were {len(error_list)} errors: \n  {joined}"
+        return f"NOT CONFORM, {len(error_list)} errors: \n  {joined}"
 
 
 class Conformance:
@@ -59,6 +62,10 @@ class Conformance:
         self.matches = {}
         self.candidates = {}
 
+        self.odapi = ODAPI(state, model, type_model)
+
+        # CDAPI(state, type_model)
+
     def check_nominal(self, *, log=False):
         """
         Perform a nominal conformance check
@@ -220,7 +227,8 @@ class Conformance:
             suc = self.read_attribute(tm_element, "source_upper_cardinality")
             if slc or suc:
                 mult = (
-                    slc if slc != None else float("-inf"),
+                    # slc if slc != None else float("-inf"),
+                    slc if slc != None else 0,
                     suc if suc != None else float("inf")
                 )
                 self.source_multiplicities[tm_name] = mult
@@ -228,7 +236,8 @@ class Conformance:
             tuc = self.read_attribute(tm_element, "target_upper_cardinality")
             if tlc or tuc:
                 mult = (
-                    tlc if tlc != None else float("-inf"),
+                    # tlc if tlc != None else float("-inf"),
+                    tlc if tlc != None else 0,
                     tuc if tuc != None else float("inf")
                 )
                 self.target_multiplicities[tm_name] = mult
@@ -381,15 +390,16 @@ class Conformance:
 
         funcs = {
             'read_value': self.state.read_value,
-            'get_value': lambda el: od.read_primitive_value(self.bottom, el, self.type_model)[0],
-            'get_target': lambda el: self.bottom.read_edge_target(el),
-            'get_source': lambda el: self.bottom.read_edge_source(el),
-            'get_slot': od.OD(self.type_model, self.model, self.state).get_slot,
-            'get_all_instances': self.get_all_instances,
-            'get_name': self.get_name,
-            'get_type_name': self.get_type_name,
-            'get_outgoing': self.get_outgoing,
-            'get_incoming': self.get_incoming,
+            'get_value': self.odapi.get_value,
+            'get_target': self.odapi.get_target,
+            'get_source': self.odapi.get_source,
+            'get_slot': self.odapi.get_slot,
+            'get_slot_value': self.odapi.get_slot_value,
+            'get_all_instances': self.odapi.get_all_instances,
+            'get_name': self.odapi.get_name,
+            'get_type_name': self.odapi.get_type_name,
+            'get_outgoing': self.odapi.get_outgoing,
+            'get_incoming': self.odapi.get_incoming,
         }
         # print("evaluating constraint ...", code)
         loc = {**kwargs, }
@@ -404,30 +414,6 @@ class Conformance:
         # print('result =', result)
         return result
 
-    def get_name(self, element: UUID):
-        return [name for name in self.bottom.read_keys(self.model) if self.bottom.read_outgoing_elements(self.model, name)[0] == element][0]
-
-    def get_type_name(self, element: UUID):
-        type_node = self.bottom.read_outgoing_elements(element, "Morphism")[0]
-        for type_name in self.bottom.read_keys(self.type_model):
-            if self.bottom.read_outgoing_elements(self.type_model, type_name)[0] == type_node:
-                return type_name
-
-    def get_all_instances(self, type_name: str, include_subtypes=True):
-        result = [e_name for e_name, t_name in self.type_mapping.items() if t_name == type_name]
-        if include_subtypes:
-            for subtype_name in self.sub_types[type_name]:
-                # print(subtype_name, 'is subtype of ')
-                result += [e_name for e_name, t_name in self.type_mapping.items() if t_name == subtype_name]
-        result_with_ids = [ (e_name, self.bottom.read_outgoing_elements(self.model, e_name)[0]) for e_name in result]
-        return result_with_ids
-
-    def get_outgoing(self, element: UUID, assoc_or_attr_name: str):
-        return od.find_outgoing_typed_by(self.bottom, src=element, type_node=self.bottom.read_outgoing_elements(self.type_model, assoc_or_attr_name)[0])
-
-    def get_incoming(self, element: UUID, assoc_or_attr_name: str):
-        return od.find_incoming_typed_by(self.bottom, tgt=element, type_node=self.bottom.read_outgoing_elements(self.type_model, assoc_or_attr_name)[0])
-
     def check_constraints(self):
         """
         Check whether all constraints defined for a model are respected
@@ -451,10 +437,11 @@ class Conformance:
         for type_name in self.bottom.read_keys(self.type_model):
             code = get_code(type_name)
             if code != None:
-                instances = self.get_all_instances(type_name, include_subtypes=self.constraint_check_subtypes)
+                instances = self.odapi.get_all_instances(type_name, include_subtypes=self.constraint_check_subtypes)
                 for obj_name, obj_id in instances:
-                    result = self.evaluate_constraint(code, this=obj_id)
                     description = f"Local constraint of \"{type_name}\" in \"{obj_name}\""
+                    # print(description)
+                    result = self.evaluate_constraint(code, this=obj_id)
                     check_result(result, description)
 
         # global constraints

services/od.py

@@ -78,14 +78,20 @@ class OD:
         return slot_id
 
     def get_slot(self, object_node: UUID, attr_name: str):
+        edge = self.get_slot_link(object_node, attr_name)
+        slot_ref = self.bottom.read_edge_target(edge)
+        return slot_ref
+
+    def get_slot_link(self, object_node: UUID, attr_name: str):
         # I really don't like how complex and inefficient it is to read an attribute of an object...
         class_name = self._get_class_of_object(object_node)
         attr_link_name = self.get_attr_link_name(class_name, attr_name)
+        if attr_link_name == None:
+            raise Exception(f"Type '{class_name}' has no attribute '{attr_name}'")
         type_edge, = self.bottom.read_outgoing_elements(self.type_model, attr_link_name)
         for outgoing_edge in self.bottom.read_outgoing_edges(object_node):
             if type_edge in self.bottom.read_outgoing_elements(outgoing_edge, "Morphism"):
-                slot_ref = self.bottom.read_edge_target(outgoing_edge)
-                return slot_ref
+                return outgoing_edge
 
     def get_slots(self, object_node):
         attrlink_node = get_scd_mm_attributelink_node(self.bottom)
@@ -111,32 +117,28 @@ class OD:
         integer_t.create(value)
         # name = 'int'+str(value) # name of the ref to the created integer
         # By convention, the type model must have a ModelRef named "Integer"
-        self.create_model_ref(name, "Integer", int_node)
-        return name
+        return self.create_model_ref(name, "Integer", int_node)
 
     def create_boolean_value(self, name: str, value: bool):
         from services.primitives.boolean_type import Boolean
         bool_node = self.bottom.create_node()
         bool_service = Boolean(bool_node, self.bottom.state)
         bool_service.create(value)
-        self.create_model_ref(name, "Boolean", bool_node)
-        return name
+        return self.create_model_ref(name, "Boolean", bool_node)
 
     def create_string_value(self, name: str, value: str):
         from services.primitives.string_type import String
         string_node = self.bottom.create_node()
         string_t = String(string_node, self.bottom.state)
         string_t.create(value)
-        self.create_model_ref(name, "String", string_node)
-        return name
+        return self.create_model_ref(name, "String", string_node)
 
     def create_actioncode_value(self, name: str, value: str):
         from services.primitives.actioncode_type import ActionCode
         actioncode_node = self.bottom.create_node()
         actioncode_t = ActionCode(actioncode_node, self.bottom.state)
         actioncode_t.create(value)
-        self.create_model_ref(name, "ActionCode", actioncode_node)
-        return name
+        return self.create_model_ref(name, "ActionCode", actioncode_node)
 
     # Identical to the same SCD method:
     def create_model_ref(self, name: str, type_name: str, model: UUID):
@@ -184,7 +186,10 @@ class OD:
         link_id = self._create_link(link_name, type_edge, src_obj_node, tgt_obj_node)
         return link_id
 
+    # used for attribute-links and association-links
     def _create_link(self, link_name: str, type_edge: UUID, src_obj_node: UUID, tgt_obj_node: UUID):
+        # print('create_link', link_name, type_edge, src_obj_node, tgt_obj_node)
+
         # the link itself is unlabeled:
         link_edge = self.bottom.create_edge(src_obj_node, tgt_obj_node)
         # it is only in the context of the model, that the link has a name:

util/prompt.py

@@ -14,4 +14,26 @@ def yes_no(msg: str):
 
 def pause():
    print("press any key...")
-   input()
+   input()
+
+def choose(msg:str, options):
+   arr = []
+   for i, (key, result) in enumerate(options):
+      print(f"  {i}. {key}")
+      arr.append(result)
+   if len(arr) == 0:
+      return
+   return __choose(msg, arr)
+
+def __choose(msg: str, arr):
+   sys.stdout.write(f"{msg} ")
+   try:
+      raw = input()
+      choice = int(raw) # may raise ValueError
+      if choice >= 0 and choice < len(arr):
+         return arr[choice]
+   except ValueError:
+      pass
+
+   print("Invalid option")
+   return __choose(msg, arr)