1 files changed, 96 insertions, 0 deletions
diff --git a/ReckonPrimer.activity/exercises/exercise.py b/ReckonPrimer.activity/exercises/exercise.py
new file mode 100755
index 0000000..c3bfcc9
--- /dev/null
+++ b/ReckonPrimer.activity/exercises/exercise.py
@@ -0,0 +1,96 @@
+# -*- coding: utf-8 -*-
+from functions import contain, collect_digits, make_line, make_input
+from functions import make_line_remainder, make_input_remainder
+
+class Exercise:
+    
+    EXERCISES = {}
+    
+    """This is the base class for the individual exercises.
+    An exercise is characterized by a topic. A topic determines the 
+    fields of the settings self._sett and public methods of Exercise.
+    The values of self._sett may vary from exercise to exercise.
+    """
+    def __init__(self):
+        """ An Exercise stores data on evaluation, i.e date, duration TODO.
+        The preliminary format deals with errors only and is
+        [(None, errors), (settings, errors)], where None indicates, 
+        that the settings are not changed by the Learner,
+        and settings indicates updates done by the Learner.
+        The list allows to append the current errors to the previous ones,
+        and even to do an Exercise subsequently several times;
+        thus the most recent errors are at the end of the list. """
+        self._eval = []
+        """ The settings determine the generation of calculations.
+        The fields of the settings are determined by self._sett['topic'];
+        the values of the settings are different for different Exercises.
+        self._sett['calclines'] determines the # of lines in a calculation."""
+        self._sett = None
+        """ Calculations are generated according to the settings. """
+        self._calcs = None
+        """ An Exercise needs the Display for updating the settings"""
+        self._display = None
+
+    def get_setting(self):
+        return self._sett
+        
+    def update_setting(self, sett):
+        """ Update the settings and generate calculations accordingly. """
+        self._sett = sett
+        self._calcs = self._generate_calcs()
+
+    def get_calcs(self):
+        """ Get all calculations generated by the current settings. """
+        return self._calcs
+
+    def get_next_calc(self):
+        """ Get the next calculation from the Exercise.
+        TODO.WN091123: handle exception after last exercise. """
+        return (self._calcs).pop()
+    
+    def count(self):
+        """ Return the number of calculations generated by
+        the current settings """
+        return len(self._calcs)
+
+    #===== methods of subclasses different for topic-specific settings
+    def format(self, calc):
+        """ Prepare the representation of a calculation for Display.
+        This method is public for eventual use on calculations
+        coming through the net (TODO cooperative games, etc)"""
+        pass
+
+    def _generate_calcs(self):
+        """ Generate calculations according to topic-specific settings.
+        Called on each call of update_setting"""
+        pass
+
+    def define_buttons(self):
+        """ Define buttons for update settings including callbacks.
+        The widgets are local to exerc-instances and attached to the display:
+        #   self.butt.connect('toggled',self.butt_callback)
+        #   self._display.settings_table.attach(self.butt, 1,2,3,4)
+        And the callbacks run locally, but read and write in the display:
+        # def butt_callback(self, widget)
+        #   if widget.get_active():
+        #     self._display._sett['+'] = True
+        """
+        pass
+
+    def set_buttons(self, sett):
+        """ Display buttons according to the current setting sett. """
+        pass
+
+    #===== methods is used by more than one subclass
+    def format_addsub_simp(self, (calc, linepos)):
+        """ Prepare the representation of a calculation for Display
+        on 1 line. Used within several subclasses. """
+        #@print('in Display.format_addsub_simp: calc=', (calc, linepos))#@
+        _ccs = collect_digits(calc)
+        #print('in Exercise.format_addsub_simp: _ccs=',_ccs )
+        _l0 = make_line(_ccs, linepos)
+        _ip = make_input(_ccs, linepos)
+        #@print('in Display.format_addsub_simp: return=', ([_l0], _ip)) #@
+        return ([_l0], _ip)
+#return ([[' ', '1', '0', ' ', '-', ' ', '7', ' ', '=', ' ', '_', ' ']], [(0, 10, '3', ' 10 - 7 = _ ', ' 10 - 7 = 3 ', [' ', '1', '0', ' ', '-', ' ', '7', ' ', '=', ' ', '3', ' '])])
+