Parse continuous signals and build valid AST

design/howto

@@ -12,8 +12,8 @@ continuous_signal
                 hyperlink?
                 PROVIDED expression e=end
                 (PRIORITY p=INT end)?
-                transition
-        ->      ^(PROVIDED cif? hyperlink? expression $p? $e? transition)
+                transition?
+        ->      ^(PROVIDED expression cif? hyperlink? $p? $e? transition?)
         ;
 
 A new token ("PROVIDED") may be needed and must be added at several places
@@ -23,7 +23,10 @@ in the ANTLR grammar:
     - in the list of tokens (tokens { ... })
 
 notes:
-    - "cif?" and "hyperlink?" are optional
+    - "cif" and "hyperlink" are optional
+    - the "transition" is also optional, to allow partial model saving
+    - the expression is always the first child, since it does not have a
+      dedicated token, and is the only mandatory field
     - "end" corresponds to the COMMENT part
 
 then the new production is added as a child option to the (existing) "state":
@@ -93,6 +96,45 @@ class State(object):
         self.continuous_signals = []
 
 Then create the new class, using the same structure as another class of a
-feature of the same family.
+feature of the same family - here, we inherit from Input. The class is very
+simple:
 
+class ContinuousSignal(Input):
+    ''' AST Entry for the Continuous Signal '''
+    def __init__(self):
+        ''' Difference with Input: trigger is an expression '''
+        super(ContinuousSignal, self).__init__()
+        # Expression triggering the transition
+        self.trigger = None
+        # Priority (integer)
+        self.priority = 0
 
+    def trace(self):
+        ''' Debug output for a Continuous signal '''
+        return u'PROVIDED {exp} ({l},{c})'.format(exp=self.inputString,
+                l=self.line, c=self.charPositionInLine)
+
+We are done with the AST, we can close ogAST.py
+
+4) Back to ogParser.py
+
+Now we can parse the construct and create the AST entries we just defined.
+In the state() function, we replace the placeholder we added at step 2:
+
+        (...)
+        elif child.type == lexer.PROVIDED:
+            # Continuous signal
+            provided_part, err, warn = continuous_signal(child, state_def,
+                                                         context)
+            state_def.continuous_signals.append(provided_part)
+            warnings.extend(warn)
+            errors.extend(err)
+
+Then we can implement the continuous_signal function.
+
+
+def continuous_signal(root, parent, context):
+    ''' Parse a PROVIDED clause in a continuous signal '''
+    i = ogAST.ContinuousSignal()
+    (...)
+    return i, errors, warnings

opengeode/icons.py

@@ -2,7 +2,7 @@
 # Resource object code
 #
-# Created: Sun Nov 22 08:45:14 2015
+# Created: Sun Nov 22 17:13:10 2015
 #      by: The Resource Compiler for PySide (Qt v4.8.6)
 #
 # WARNING! All changes made in this file will be lost!

opengeode/ogAST.py

@@ -27,7 +27,7 @@
 
     See AdaGenerator.py for an example of use.
 
-    Copyright (c) 2012-2013 European Space Agency
+    Copyright (c) 2012-2015 European Space Agency
 
     Designed and implemented by Maxime Perrotin
 
@@ -611,6 +611,21 @@ class Connect(Input):
         return u'CONNECT {exp} ({l},{c})'.format(exp=self.inputString,
                 l=self.line, c=self.charPositionInLine)
 
+class ContinuousSignal(Input):
+    ''' AST Entry for the Continuous Signal '''
+    def __init__(self):
+        ''' Difference with Input: trigger is an expression '''
+        super(ContinuousSignal, self).__init__()
+        # Expression triggering the transition
+        self.trigger = None
+        # Priority (integer)
+        self.priority = 0
+
+    def trace(self):
+        ''' Debug output for a Continuous signal '''
+        return u'PROVIDED {exp} ({l},{c})'.format(exp=self.inputString,
+                l=self.line, c=self.charPositionInLine)
+
 
 class Start(object):
     ''' AST Entry for the START symbol '''

opengeode/ogParser.py

@@ -2749,6 +2749,55 @@ def process_definition(root, parent=None, context=None):
     return process, errors, warnings
 
 
+def continuous_signal(root, parent, context):
+    ''' Parse a PROVIDED clause in a continuous signal '''
+    i = ogAST.ContinuousSignal()
+    warnings, errors = [], []
+    # Keep track of the number of terminator statements in the transition
+    # useful if we want to render graphs from the SDL model
+    terminators = len(context.terminators)
+    i.trigger, err0, warn0 = expression(root.getChild(0), context)
+    for child in root.children[1:]:
+        if child.type == lexer.CIF:
+            # Get symbol coordinates
+            i.pos_x, i.pos_y, i.width, i.height = cif(child)
+
+
+#           # Report errors with symbol coordinates
+#           errors = [[e, [i.pos_x or 0, i.pos_y or 0], []] for e in errors]
+#           warnings = [[w, [i.pos_x or 0, i.pos_y or 0], []]
+#                        for w in warnings]
+        elif child.type == lexer.INT:
+            # Priority
+            i.priority = int(child.text)
+        elif child.type == lexer.TRANSITION:
+            trans, err, warn = transition(child, parent=i, context=context)
+            errors.extend(err)
+            warnings.extend(warn)
+            i.transition = trans
+            # Associate a reference to the transition to the list of inputs
+            # The reference is an index to process.transitions table
+            context.transitions.append(trans)
+            i.transition_id = len(context.transitions) - 1
+        elif child.type == lexer.COMMENT:
+            i.comment, _, _ = end(child)
+        elif child.type == lexer.HYPERLINK:
+            i.hyperlink = child.getChild(0).toString()[1:-1]
+        elif child.type == 0:
+            # Syntax error caught by the parser, no need to report again
+            pass
+        else:
+            warnings.append('Unsupported INPUT child type: {}'
+                            .format(child.type))
+    # At the end of the input parsing, get the the list of terminators that
+    # follow the input transition by making a diff with the list at process
+    # level (we counted the number of terminators before parsing the input)
+    i.terminators = list(context.terminators[terminators:])
+    return i, errors, warnings
+
+
+
+
 def input_part(root, parent, context):
     ''' Parse an INPUT - set of TASTE provided interfaces '''
     i = ogAST.Input()
@@ -2958,7 +3007,12 @@ def state(root, parent, context):
         elif child.type == lexer.HYPERLINK:
             state_def.hyperlink = child.getChild(0).toString()[1:-1]
         elif child.type == lexer.PROVIDED:
-            sterr.append('Continuous signals are not supported yet')
+            # Continuous signal
+            provided_part, err, warn = continuous_signal(child, state_def,
+                                                         context)
+            state_def.continuous_signals.append(provided_part)
+            warnings.extend(warn)
+            errors.extend(err)
         elif child.type == 0:
             # Parser error, already caught
             pass

opengeode/sdl92Lexer.py

-# $ANTLR 3.1.3 Mar 17, 2009 19:23:44 sdl92.g 2015-11-22 08:45:16
+# $ANTLR 3.1.3 Mar 17, 2009 19:23:44 sdl92.g 2015-11-22 17:13:13
 
 import sys
 from antlr3 import *

sdl92.g

@@ -627,8 +627,8 @@ continuous_signal
                 hyperlink?
                 PROVIDED expression e=end
                 (PRIORITY p=INT end)?
-                transition
-        ->      ^(PROVIDED cif? hyperlink? expression $p? $e? transition)
+                transition?
+        ->      ^(PROVIDED expression cif? hyperlink? $p? $e? transition?)
         ;