Partial support of nested states, with Sdl2010 syntax

AdaGenerator.py

@@ -124,6 +124,54 @@ def _process(process):
                         t=var_type.ReferencedTypeName.replace('-','_'),
                         default=' := ' + dstr if def_value else ''))
 
+    # Flatten the nested states, add states to the process state list
+    # Requires renaming of nested states and setting chaining of transitions
+    def update_terminator(context, term, process):
+        '''Set next_id, identifying the next transition to run '''
+        if term.inputString.lower() in (st.statename.lower()
+                                for st in context.composite_states):
+            if not term.via:
+                term.next_id = context.mapping \
+                                          [term.inputString.lower() + '_START']
+            else:
+                term.next_id = context.mapping[term.inputString.lower()
+                                               + '_'
+                                               + term.via.lower()
+                                               + '_START']
+
+    def update_composite_state(state, process):
+        ''' Rename inner states, recursively, and add inner transitions
+            to process, updating indexes, and update terminators
+        '''
+        trans_idx = len(process.transitions)
+        state.mapping = {state.statename + '_' + key:state.mapping.pop(key)
+                         for key in state.mapping.keys()}
+        process.transitions.extend(state.transitions)
+        for key, value in state.mapping.viewitems():
+            # Update transition indices
+            if isinstance(value, int):
+                state.mapping[key] = value + trans_idx
+            else:
+                for inp in value:
+                    inp.transition_id += trans_idx
+        process.mapping.update(state.mapping)
+        for inner in state.composite_states:
+            inner.statename = state.statename + '_' + inner.statename
+            update_composite_state(inner, process)
+        for each in state.terminators:
+            # Update state names in terminators and set next transition id
+            if each.kind == 'next_state':
+                each.inputString = state.statename + '_' + each.inputString
+                update_terminator(state, each, process)
+    for each in process.composite_states:
+        update_composite_state(each, process)
+
+    # Update terminators at process level
+    for each in process.terminators:
+        if each.kind == 'next_state':
+            update_terminator(process, each, process)
+
+
     # Add the process states list to the process-level variables
     states_decl = 'type states is ('
     states_decl += ', '.join(process.mapping.iterkeys()) + ');'
@@ -136,12 +184,13 @@ def _process(process):
                                                          .format(process_name))
 
     # Add the declaration of the runTransition procedure
-    process_level_decl.append('procedure runTransition(trId: Integer);')
+    process_level_decl.append('procedure runTransition(Id: Integer);')
 
     # Generate the code of the start transition:
     start_transition = ['begin']
     start_transition.append('runTransition(0);')
 
+
     mapping = {}
     # Generate the code for the transitions in a mapping input-state
     input_signals = [sig['name'] for sig in process.input_signals]
@@ -150,7 +199,8 @@ def _process(process):
     for input_signal in input_signals:
         mapping[input_signal] = {}
         for state_name, input_symbols in process.mapping.viewitems():
-            if state_name != 'START':
+            if isinstance(input_symbols, list):
+                # Start symbols have no list of inputs
                 for i in input_symbols:
                     if input_signal.lower() in (inp.lower() for
                                                inp in i.inputlist):
@@ -224,7 +274,7 @@ package {process_name} is'''.format(process_name=process_name,
         taste_template.append('begin')
         taste_template.append('case state is')
         for state in process.mapping.viewkeys():
-            if state == 'START':
+            if state.endswith('START'):
                 continue
             taste_template.append('when {state} =>'.format(state=state))
             input_def = mapping[signal['name']].get(state)
@@ -293,7 +343,9 @@ package {process_name} is'''.format(process_name=process_name,
                 'pragma import(C, RESET_{timer}, "{proc}_RI_reset_{timer}");'
                 .format(timer=timer, proc=process_name))
 
-    taste_template.append('procedure runTransition(trId: Integer) is')
+    taste_template.append('procedure runTransition(Id: Integer) is')
+    taste_template.append('trId : Integer := Id;')
+
 
     # Generate the code for all transitions
     code_transitions = []
@@ -327,6 +379,10 @@ package {process_name} is'''.format(process_name=process_name,
     taste_template.extend(decl)
     taste_template.append('begin')
 
+    # Generate a loop that ends when a next state is reached
+    # (there can be chained transition when entering a nested state)
+    taste_template.append('while (trId /= -1) loop')
+
     # Generate the switch-case on the transition id
     taste_template.append('case trId is')
 
@@ -342,10 +398,18 @@ package {process_name} is'''.format(process_name=process_name,
     taste_template.append('null;')
 
     taste_template.append('end case;')
+    if code_labels:
+        # Due to nested states (chained transitions) jump over label code
+        # (NEXTSTATEs do not return from runTransition)
+        taste_template.append('goto next_transition;')
 
     # Add the code for the floating labels
     taste_template.extend(code_labels)
 
+    if code_labels:
+        taste_template.append('<<next_transition>>')
+        taste_template.append('null;')
+    taste_template.append('end loop;')
     taste_template.append('end runTransition;')
     taste_template.append('\n')
 
@@ -1233,12 +1297,12 @@ def _transition(tr):
                 code.append('<<{label}>>'.format(
                     label=tr.terminator.label.inputString))
             if tr.terminator.kind == 'next_state':
+                code.append('trId := ' + str(tr.terminator.next_id) + ';')
                 if tr.terminator.inputString.strip() != '-':
                     # discard the dash state (remain in the same state)
-                    code.append('state := {nextState};'.format(
+                    if tr.terminator.next_id == -1:
+                        code.append('state := {nextState};'.format(
                                  nextState=tr.terminator.inputString))
-                # In any case, return to avoid code of floating labels
-                code.append('return;')
             elif tr.terminator.kind == 'join':
                 code.append('goto {label};'.format(
                     label=tr.terminator.inputString))
@@ -1247,11 +1311,15 @@ def _transition(tr):
                 # TODO
             elif tr.terminator.kind == 'return':
                 string = ''
-                if tr.terminator.return_expr:
-                    stmts, string, local = generate(tr.terminator.return_expr)
-                    code.extend(stmts)
-                    local_decl.extend(local)
-                code.append('return{};'.format(' ' + string if string else ''))
+                if tr.terminator.next_id == -1:
+                    if tr.terminator.return_expr:
+                        stmts, string, local = generate\
+                                                    (tr.terminator.return_expr)
+                        code.extend(stmts)
+                        local_decl.extend(local)
+                    code.append('return{};'.format(' ' + string if string else ''))
+                else:
+                    code.append('trId := ' + str(tr.terminator.next_id) + ';')
     if empty_transition:
         # If transition does not have any statement, generate an Ada 'null;'
         code.append('null;')
@@ -1329,6 +1397,15 @@ def _inner_procedure(proc):
                 name=var_name,
                 sort=typename,
                 default=' := ' + dstr if def_value else ''))
+
+        # Look for labels in the diagram and transform them in floating labels
+        for idx in xrange(len(proc.content.floating_labels)):
+            for new_floating in find_labels(
+                          proc.content.floating_labels[idx].transition):
+                proc.content.floating_labels.append(new_floating)
+        for new_floating in find_labels(proc.content.start.transition):
+            proc.content.floating_labels.append(new_floating)
+
         tr_code, tr_decl = generate(proc.content.start.transition)
         # Generate code for the floating labels
         code_labels = []

Renderer.py

@@ -91,6 +91,10 @@ def _automaton(ast, scene):
     if ast.start:
         top_level_symbols.append(render(ast.start, scene, ast.states))
 
+    # Render named start symbols in nested states
+    for each in ast.named_start:
+        top_level_symbols.append(render(each, scene, ast.states))
+
     # Render floating labels
     for label in ast.floating_labels:
         top_level_symbols.append(render(label, scene, ast.states))
@@ -128,6 +132,9 @@ def _state(ast, scene, states, terminators, parent=None):
 
     for inp in ast.inputs:
         render(inp, scene=scene, parent=new_state, states=states)
+
+    new_state.nested_scene = ast.composite or ogAST.CompositeState()
+
     return new_state
 
 
@@ -161,6 +168,18 @@ def _start(ast, scene, states, parent=None):
     return start_symbol
 
 
+@render.register(ogAST.CompositeState_start)
+def _start(ast, scene, states, parent=None):
+    ''' Add an editable start symbol to a scene (in composite states) '''
+    _ = parent
+    start_symbol = sdlSymbols.StateStart(ast)
+    scene.addItem(start_symbol)
+    if ast.transition:
+        render(ast.transition,
+                      scene=scene, parent=start_symbol, states=states)
+    return start_symbol
+
+
 @render.register(ogAST.Procedure_start)
 def _procedure_start(ast, scene, states, parent=None):
     ''' Add the procedure start symbol to a scene '''

genericSymbols.py

@@ -561,6 +561,8 @@ class Symbol(QObject, QGraphicsPathItem, object):
     redbold = ()
     # Specify if the symbol can be drawn with anti-aliasing
     _antialiasing = True
+    # Specify if the symbol text can be edited
+    editable = True
 
     def __init__(self, parent=None):
         '''
@@ -1342,7 +1344,7 @@ class HorizontalSymbol(Symbol, object):
         super(HorizontalSymbol, self).__init__(parent)
         self.minDistanceToSymbolAbove = 20
         self.connection = None
-        if text:
+        if self.editable:
             self.text = EditableText(parent=self, text=text,
                     hyperlink=hyperlink)
         if parent:
@@ -1506,7 +1508,10 @@ class VerticalSymbol(Symbol, object):
             x=None, y=None, hyperlink=None):
         super(VerticalSymbol, self).__init__(parent)
         self.connection = None
-        self.text = EditableText(parent=self, text=text, hyperlink=hyperlink)
+        if self.editable:
+            self.text = EditableText(parent=self,
+                                     text=text,
+                                     hyperlink=hyperlink)
         self.minDistanceToSymbolAbove = 15
         if parent:
             local_pos = self.mapFromScene(0, y or 0)

icons.py

@@ -2,8 +2,8 @@
 
 # Resource object code
 #
-# Created: Fri Feb 28 10:41:17 2014
-#      by: The Resource Compiler for PySide (Qt v4.8.4)
+# Created: Fri Mar 7 19:56:41 2014
+#      by: The Resource Compiler for PySide (Qt v4.8.6)
 #
 # WARNING! All changes made in this file will be lost!
 

ogAST.py

@@ -268,7 +268,7 @@ class Answer(object):
     ''' AST Entry for a decision answer '''
     def __init__(self):
         ''' One ANSWER of a DECISION '''
-        self.inputString = 'case'
+        self.inputString = ''
         self.line = None
         self.charPositionInLine = None
         self.pos_x = 0
@@ -303,7 +303,7 @@ class Task(object):
     ''' AST Entry for TASKS '''
     def __init__(self):
         ''' Initialize TASK attributes (set of ASSIGN statements) '''
-        self.inputString = 'x := 1'
+        self.inputString = ''
         self.line = None
         self.charPositionInLine = None
         self.pos_x = 0
@@ -342,7 +342,7 @@ class TaskForLoop(Task):
 
 class Output(object):
     ''' AST Entry for OUTPUT statements '''
-    def __init__(self, defName='RI'):
+    def __init__(self, defName=''):
         ''' Set of OUTPUT statements '''
         self.inputString = defName
         self.pos_x = 0
@@ -392,6 +392,8 @@ class Terminator(object):
         self.return_expr = None
         # via clause, used for entering nested state with an entry point
         self.via = None
+        # some transitions can be chained, when entering/leaving nested states
+        self.next_id = -1
 
     def __repr__(self):
         ''' Debug output for terminators '''
@@ -406,7 +408,7 @@ class Label(object):
     def __init__(self):
         ''' Initialize the label attributes '''
         # inputString holds the label name
-        self.inputString = 'Here'
+        self.inputString = ''
         self.pos_x = 0
         self.pos_y = 0
         self.width = 70
@@ -475,7 +477,7 @@ class Input(object):
     def __init__(self):
         ''' Initialize the Input attributes '''
         # inputString is the user text, it can contain several inputs
-        self.inputString = 'PI'
+        self.inputString = ''
         self.pos_x = 0
         self.pos_y = 0
         self.width = 70
@@ -526,7 +528,7 @@ class Start(object):
 
     def __repr__(self):
         ''' Debug output for a START symbol '''
-        return 'START'
+        return 'START {}'.format(self.inputString)
 
 
 class Procedure_start(Start):
@@ -534,6 +536,11 @@ class Procedure_start(Start):
     pass
 
 
+class CompositeState_start(Start):
+    ''' Composite state start symbol - inherits from Start, can have a name '''
+    pass
+
+
 class Comment(object):
     ''' AST Entry for COMMENT symbols '''
     def __init__(self):
@@ -575,6 +582,8 @@ class State(object):
         self.comment = None
         # optional hyperlink
         self.hyperlink = None
+        # optional composite state content (type CompositeState)
+        self.composite = None
 
     def __repr__(self):
         ''' Debug output for a STATE symbol '''
@@ -588,7 +597,7 @@ class TextArea(object):
     def __init__(self):
         ''' Text area (raw content for rendering only) '''
         self.inputString = '-- Declare your variables\n\n' \
-                           '-- Syntax: DCL <variable name> <type name>;'
+                           '-- Syntax: DCL <variable name> <type name>;\n\n'
         # DCL variables in the text area {name: (sort, default_value), ...}
         self.variables = {}
         self.line = None
@@ -617,13 +626,14 @@ class Automaton(object):
         self.start = None
         self.floating_labels = []
         self.states = []
+        self.named_start = []
 
 
 class Procedure(object):
     ''' Internal procedure definition '''
     def __init__(self):
         ''' Procedure AST default value '''
-        self.inputString = 'Proc'
+        self.inputString = ''
         self.line = None
         self.charPositionInLine = None
         # Set default coordinates and width/height
@@ -712,6 +722,9 @@ class Process(object):
         # list of type Transition - use 'mapping' to map index to inputs/states
         self.transitions = []
 
+        # list of type CompositeState
+        self.composite_states = []
+
         # Set of symbols contained in the process (type Automaton)
         # (Includes inner procedures)
         self.content = Automaton(parent=self)
@@ -720,6 +733,27 @@ class Process(object):
         self.timers = []
 
 
+class CompositeState(Process):
+    '''
+        Composite states: the difference with Process is that they can have:
+        - several START elements, that correspond to state entry points,
+        - state exit points (with RETURN terminators)
+        - entry and exit procedures
+    '''
+    def __init__(self):
+        super(CompositeState, self).__init__()
+        self.statename = ''
+        self.state_entrypoints = []
+        self.state_exitpoints = []
+        # Special entry and exit procedures (named "entry" and "exit")
+        self.entry_procedure = None
+        self.exit_procedure = None
+        # Body can contain text areas, procedures, composite states,
+        # one nameless START, named START (one per entrypoint), states,
+        # and floating labels.
+        # XXX check what to do with local DCL and timers
+
+
 class Block(object):
     ''' AST for a BLOCK entity '''
     def __init__(self):

opengeode.py

@@ -53,7 +53,7 @@ from PySide import QtSvg
 from genericSymbols import Symbol, Comment, EditableText, Cornergrabber
 from sdlSymbols import(Input, Output, Decision, DecisionAnswer, Task,
         ProcedureCall, TextSymbol, State, Start, Join, Label, Procedure,
-        ProcedureStart, ProcedureStop)
+        ProcedureStart, ProcedureStop, StateStart)
 
 # Icons and png files generated from the resource file:
 import icons  # NOQA
@@ -128,7 +128,9 @@ ACTIONS = {
     'procedure': [ProcedureStart, Task, Decision,
                   DecisionAnswer, Output, ProcedureCall, TextSymbol,
                   Comment, Label, Join, ProcedureStop],
-    'statechart': []
+    'statechart': [],
+    'state': [StateStart, State, Input, Task, Decision, DecisionAnswer, Output,
+              ProcedureCall, TextSymbol, Comment, Label, Join, ProcedureStop]
 }
 
 
@@ -256,7 +258,10 @@ class SDL_Scene(QtGui.QGraphicsScene, object):
     scene_left = QtCore.Signal()
 
     def __init__(self, context='process'):
-        ''' Create an SDL Scene for a given context (process or procedure) '''
+        '''
+            Create an SDL Scene for a given context:
+            process, procedure or composite state
+        '''
         super(SDL_Scene, self).__init__()
         self.mode = 'idle'
         self.context = context
@@ -273,7 +278,8 @@ class SDL_Scene(QtGui.QGraphicsScene, object):
         # buttonSelected is used to set which symbol to draw
         # on next scene click (see mousePressEvent)
         self.button_selected = None
-        self.setBackgroundBrush(QtGui.QBrush(QtGui.QImage(':icons/texture.png')))
+        self.setBackgroundBrush(QtGui.QBrush(
+                                           QtGui.QImage(':icons/texture.png')))
         self.messages_window = None
         self.click_coordinates = None
         self.process_name = 'opengeode'
@@ -922,9 +928,9 @@ class SDL_Scene(QtGui.QGraphicsScene, object):
             # When creating a new decision, add two default answers
             self.place_symbol(item_type=DecisionAnswer, parent=item)
             self.place_symbol(item_type=DecisionAnswer, parent=item)
-        elif item_type == Procedure:
-            # Create a sub-scene for the procedure
-            subscene = SDL_Scene(context='procedure')
+        elif item_type in (Procedure, State):
+            # Create a sub-scene for the procedure or nested state
+            subscene = SDL_Scene(context=item_type.__name__.lower())
             subscene.messages_window = self.messages_window
             item.nested_scene = subscene
 

opengeode.qrc

@@ -12,6 +12,7 @@
      <file>icons/procedurestop.png</file>
      <file>icons/procedure.png</file>
      <file>icons/start.png</file>
+     <file>icons/statestart.png</file>
      <file>icons/state.png</file>
      <file>icons/task.png</file>
      <file>icons/textsymbol.png</file>

sdl92.g

@@ -111,8 +111,9 @@ tokens {
         BLOCK;
         PARAMNAMES;
         ASN1;
-        FLOATING_LABEL; 
+        FLOATING_LABEL;
         COMPOSITE_STATE;
+        CONNECT;
 }
 
 
@@ -307,7 +308,7 @@ floating_label
 
 
 state
-        :       cif? 
+        :       cif?
                 hyperlink?
                 STATE statelist e=end
                 (state_part)*
@@ -317,7 +318,7 @@ state
 
 statelist
         :       ((statename)(',' statename)*)
-        ->      ^(STATELIST statename+) 
+        ->      ^(STATELIST statename+)
                 | ASTERISK exception_state?
         ->      ^(ASTERISK exception_state?);
 
@@ -330,17 +331,17 @@ exception_state
 composite_state
         :       STATE statename e=end
                 SUBSTRUCTURE
-                cnx=connection_points*
+                connection_points*
                 body=composite_state_body
                 ENDSUBSTRUCTURE statename? f=end
-        ->      ^(COMPOSITE_STATE statename $cnx* $body $e?);
+        ->      ^(COMPOSITE_STATE statename connection_points* $body $e?);
 
 
 connection_points
-        :       IN state_entry_exit_points e=end
-        ->      ^(IN state_entry_exit_points $e?)
-                | OUT state_entry_exit_points f=end
-        ->      ^(OUT state_entry_exit_points $f?);
+        :       IN state_entry_exit_points end
+        ->      ^(IN state_entry_exit_points end?)
+                | OUT state_entry_exit_points end
+        ->      ^(OUT state_entry_exit_points end?);
 
 
 state_entry_exit_points
@@ -358,7 +359,21 @@ state_part
                 //| priority_input        // Not supported
                 | save_part               // Not supported in openGEODE
                 | spontaneous_transition
-                | continuous_signal;      // Not supoorted in openGEODE
+                | continuous_signal       // Not supoorted in openGEODE
+                | connect_part;
+
+
+// connect part is used to connect nested state exit points to a transition
+connect_part
+        :       CONNECT connect_list? end
+                transition
+        ->      ^(CONNECT connect_list? end? transition);
+
+
+connect_list
+        :       state_exit_point_name (',' state_exit_point_name)*
+                -> state_exit_point_name+
+                | ASTERISK;
 
 
 spontaneous_transition
@@ -1040,6 +1055,8 @@ dash_nextstate  :       DASH;
 connector_name  :       ID;
 signal_id       :       ID;
 statename       :       ID;
+state_exit_point_name
+                :       ID;
 state_entry_point_name
                 :       ID;
 variable_id     :       ID;

sdlSymbols.py

@@ -19,7 +19,8 @@
 
 __all__ = ['Input', 'Output', 'State', 'Task', 'ProcedureCall', 'Label',
            'Decision', 'DecisionAnswer', 'Join', 'Start', 'TextSymbol',
-           'Procedure', 'ProcedureStart', 'ProcedureStop', 'ASN1Viewer']
+           'Procedure', 'ProcedureStart', 'ProcedureStop', 'ASN1Viewer',
+           'StateStart']
 
 from genericSymbols import(
         HorizontalSymbol, VerticalSymbol, Connection, Comment)
@@ -52,7 +53,7 @@ SDL_REDBOLD = ['\\b{word}\\b'.format(word=word) for word in (
 
 
 # pylint: disable=R0904
-class Input(HorizontalSymbol, object):
+class Input(HorizontalSymbol):
     ''' SDL INPUT Symbol '''
     _unique_followers = ['Comment']
     _insertable_followers = ['Task', 'ProcedureCall', 'Output', 'Decision',
@@ -86,7 +87,6 @@ class Input(HorizontalSymbol, object):
         _, syntax_errors, ___, ____, _____ = self.parser.parseSingleElement(
                 self.common_name, self.pr())
         try:
-            # LOG.error('\n'.join(syntax_errors))
             self.scene().raise_syntax_errors(syntax_errors)
         except AttributeError:
             LOG.debug('raise_syntax_error raised an exception')
@@ -133,8 +133,14 @@ class Input(HorizontalSymbol, object):
         return '\n'.join(result)
 
 
+class Connect(Input):
+    ''' Connect point below a nested state '''
+    common_name = 'connect_part'
+    # TODO
+
+
 # pylint: disable=R0904
-class Output(VerticalSymbol, object):
+class Output(VerticalSymbol):
     ''' SDL OUTPUT Symbol '''
     _unique_followers = ['Comment']
     _insertable_followers = [
@@ -184,7 +190,7 @@ class Output(VerticalSymbol, object):
 
 
 # pylint: disable=R0904
-class Decision(VerticalSymbol, object):
+class Decision(VerticalSymbol):
     ''' SDL DECISION Symbol '''
     _unique_followers = ['Comment']
     _insertable_followers = ['DecisionAnswer', 'Task', 'ProcedureCall', 'Output',
@@ -220,7 +226,7 @@ class Decision(VerticalSymbol, object):
         for branch in self.branches():
             if not branch.last_branch_item.terminal_symbol:
                 return False
-        else:        
+        else:
             return True
 
     def branches(self):
@@ -351,7 +357,7 @@ class Decision(VerticalSymbol, object):
 
 
 # pylint: disable=R0904
-class DecisionAnswer(HorizontalSymbol, object):
+class DecisionAnswer(HorizontalSymbol):
     ''' If Decision is a "switch", DecisionAnswer is a "case" '''
     _insertable_followers = ['DecisionAnswer', 'Task', 'ProcedureCall',
                         'Output', 'Decision', 'Label']
@@ -441,7 +447,7 @@ class DecisionAnswer(HorizontalSymbol, object):
 
 
 # pylint: disable=R0904
-class Join(VerticalSymbol, object):
+class Join(VerticalSymbol):
     ''' JOIN symbol (GOTO) '''
     auto_expand = False
     arrow_head = True
@@ -453,7 +459,7 @@ class Join(VerticalSymbol, object):
 
     def __init__(self, parent=None, ast=None):
         if not ast:
-            ast = ogAST.Terminator(defName='Go')
+            ast = ogAST.Terminator(defName='')
             ast.pos_y = 0
             ast.width = 35
             ast.height = 35
@@ -491,7 +497,7 @@ class Join(VerticalSymbol, object):
                     h=int(self.boundingRect().height())))
 
 
-class ProcedureStop(Join, object):
+class ProcedureStop(Join):
     ''' Procedure STOP symbol - very similar to JOIN '''
     # Define reserved keywords for the syntax highlighter
     blackbold = SDL_BLACKBOLD
@@ -535,7 +541,7 @@ class ProcedureStop(Join, object):
 
 
 # pylint: disable=R0904
-class Label(VerticalSymbol, object):
+class Label(VerticalSymbol):
     ''' LABEL symbol '''
     _insertable_followers = [
             'Task', 'ProcedureCall', 'Output', 'Decision', 'Label']
@@ -619,7 +625,7 @@ class Label(VerticalSymbol, object):
 
 
 # pylint: disable=R0904
-class Task(VerticalSymbol, object):
+class Task(VerticalSymbol):
     ''' TASK symbol '''
     _unique_followers = ['Comment']
     _insertable_followers = [
@@ -668,7 +674,7 @@ class Task(VerticalSymbol, object):