Allow Splits to be mathematical expressions

The string representing the split is stored in the DB, along with its
decimal equivalent. When viewing an expense, the string form is shown.

diff --git a/bluechips/controllers/spend.py b/bluechips/controllers/spend.py
index cf691cce522cf74b6eb1ea4c498584c1cf3de868..d27ec40d2dc448507b8d50ef1c83a9bddaf61867 100644 (file)
--- a/bluechips/controllers/spend.py
+++ b/bluechips/controllers/spend.py
@@ -2,8 +2,10 @@
 Handle expenditures
 """
 
+from __future__ import division
 import logging
 
+import re
 from decimal import Decimal, InvalidOperation
 
 from bluechips.lib.base import *
@@ -13,6 +15,7 @@ from pylons.decorators import validate
 from pylons.decorators.secure import authenticate_form
 from pylons.controllers.util import abort
 
+import formencode
 from formencode import validators, Schema
 from formencode.foreach import ForEach
 from formencode.variabledecode import NestedVariables
@@ -22,12 +25,29 @@ from mailer import Message
 
 log = logging.getLogger(__name__)
 
+class ExpenditureExpression(validators.FancyValidator):
+    goodChars = set('1234567890.+-/*() ')
+
+    def _to_python(self, value, state):
+        if (not set(value) <= self.goodChars or
+            re.search(r'([\+\-\*\/])\1', value)):
+            raise formencode.Invalid("Expression contains illegal characters", value, state)
+
+        if value == '':
+            return value, Decimal("0")
+
+        try:
+            number = eval(value)
+            return value, Decimal(str(number))
+        except:
+            raise formencode.Invalid("Not a valid mathematical expression", value, state)
+
 
 class ShareSchema(Schema):
     "Validate individual user shares."
     allow_extra_fields = False
     user_id = validators.Int(not_empty=True)
-    amount = validators.Number(not_empty=True)
+    amount = ExpenditureExpression()
 
 
 def validate_state(value_dict, state, validator):
@@ -77,16 +97,10 @@ class SpendController(BaseController):
             c.values = {}
             for ii, user_row in enumerate(c.users):
                 user_id, user = user_row
-                shares_by_user = dict(((sp.user, sp.share) for sp
+                shares_by_user = dict(((sp.user, sp.share_text) for sp
                                        in c.expenditure.splits))
-                share = shares_by_user.get(user, 0)
-                if c.expenditure.amount == 0:
-                    percent = 0
-                else:
-                    percent = (Decimal(100) * Decimal(int(share)) /
-                               Decimal(int(c.expenditure.amount))).\
-                            quantize(Decimal("0.001"))
-                c.values['shares-%d.amount' % ii] = percent
+                share = shares_by_user.get(user, '')
+                c.values['shares-%d.amount' % ii] = share
 
         return render('/spend/index.mako')
 
@@ -112,10 +126,13 @@ class SpendController(BaseController):
 
         users = dict(meta.Session.query(model.User.id, model.User).all())
         split_dict = {}
+        split_text_dict = {}
         for share_params in shares:
             user = users[share_params['user_id']]
-            split_dict[user] = Decimal(str(share_params['amount']))
-        e.split(split_dict)
+            amount_text, amount  = share_params['amount'] or ('',Decimal('0'))
+            split_dict[user] = amount
+            split_text_dict[user] = amount_text
+        e.split(split_dict, split_text_dict)
         
         meta.Session.commit()
        

diff --git a/bluechips/model/__init__.py b/bluechips/model/__init__.py
index bb3b2d9caa4689b390e1a5a05891f4afaf9e83f7..90c8b4d559f28e931a5b67056142e2daea321d22 100644 (file)
--- a/bluechips/model/__init__.py
+++ b/bluechips/model/__init__.py
@@ -49,6 +49,7 @@ splits = sa.Table('splits', meta.metadata,
                             sa.ForeignKey('expenditures.id'), nullable=False),
                   sa.Column('user_id', sa.types.Integer,
                             sa.ForeignKey('users.id'), nullable=False),
+                  sa.Column('share_text', sa.Text, nullable=False),
                   sa.Column('share', types.DBCurrency, nullable=False)
                   )
 

diff --git a/bluechips/model/expenditure.py b/bluechips/model/expenditure.py
index 4669ad1090c740aaac7284c1903bd01cbac0d037..8fd706bfd5c358046c66ec2e68d80852c1365fb2 100644 (file)
--- a/bluechips/model/expenditure.py
+++ b/bluechips/model/expenditure.py
@@ -28,7 +28,7 @@ class Expenditure(object):
         split_percentage = Decimal(100) / Decimal(residents.count())
         self.split(dict((resident, split_percentage) for resident in residents))
     
-    def split(self, split_dict):
+    def split(self, split_dict, split_text_dict):
         """
         Split up an expenditure.
         
@@ -71,7 +71,7 @@ class Expenditure(object):
                 amounts_dict[winner] -= Currency(1)
         
         for user, share in amounts_dict.iteritems():
-            s = Split(self, user, share)
+            s = Split(self, user, share, split_text_dict[user])
             meta.Session.add(s)
 
     def involves(self, user):

diff --git a/bluechips/model/split.py b/bluechips/model/split.py
index 8bf3b2e791a31a529c492e0e3c280417842cd315..3ee1f1754da2241acb2827f72e692f8762206a75 100644 (file)
--- a/bluechips/model/split.py
+++ b/bluechips/model/split.py
@@ -1,11 +1,12 @@
 from types import Currency
 
 class Split(object):
-    def __init__(self, expenditure=None, user=None, share=Currency(0)):
+    def __init__(self, expenditure=None, user=None, share=Currency(0), share_text=u""):
         self.expenditure = expenditure
         self.user = user
         self.share = share
-    
+        self.share_text = share_text
+
     def __repr__(self):
         return '<Split: expense: %s user: %s share: %s>' % (self.expenditure,
                                                             self.user,