@@ -0,0 +1,27 @@
+# follow.py
+import os
+import time
+
+
+def follow(filename):
+    f = open(filename)
+    f.seek(0, os.SEEK_END)  # Move file pointer 0 bytes from end of file
+    while True:
+        line = f.readline()
+        if line:
+            yield line
+
+
+if __name__ == '__main__':
+    import report
+
+    portfolio = report.read_portfolio('Data/portfolio.csv')
+
+    for line in follow('Data/stocklog.csv'):
+        fields = line.split(',')
+        name = fields[0].strip('"')
+        price = float(fields[1])
+        change = float(fields[4])
+        if name in portfolio:
+            print(f'{name:>10s} {price:>10.2f} {change:>10.2f}')       
+
@@ -7,21 +7,22 @@
 import report
 
 def portfolio_cost(filename):
-    total_cost = 0.0
-    stock_price = 0.0
-    num_of_shares = 0
-    records = report.read_portfolio(filename) 
+#    total_cost = 0.0
+#    stock_price = 0.0
+#    num_of_shares = 0
+    portfolio = report.read_portfolio(filename) 
 
-    for lineno, record in enumerate(records, start=1):
-        try:
-            nshares = int(record.shares)
-            price = float(record.price)
-            total_cost += nshares * price
-        # This catches errors in int() and float() conversions above
-        except ValueError:
-            print(f'Row {lineno}: Bad row: {line}')
+#    for lineno, record in enumerate(records, start=1):
+#        try:
+#            nshares = int(record.shares)
+#            price = float(record.price)
+#            total_cost += nshares * price
+#        # This catches errors in int() and float() conversions above
+#        except ValueError:
+#            print(f'Row {lineno}: Bad row: {line}')
 
-    return total_cost
+    return portfolio.total_cost
+
 
 def main(argv):
     if len(argv) == 2:
 
@@ -0,0 +1,35 @@
+# portfolio.py
+
+class Portfolio:
+
+    def __init__(self, holdings):
+        self._holdings = holdings
+
+
+    def __iter__(self):
+        return self._holdings.__iter__()
+
+
+    def __len__(self):
+        return len(self._holdings)
+
+
+    def __getitem__(self, index):
+        return self._holdings[index]
+
+
+    def __contains__(self, name):
+        return any([s.name == name for s in self._holdings])
+
+
+    @property
+    def total_cost(self):
+        return sum([s.cost for s in self._holdings])
+
+
+    def tabulate_shares(self):
+        from collections import Counter
+        total_shares = Counter()
+        for s in self._holdings:
+            total_shares[s.name] += s.shares
+        return total_shares
@@ -7,12 +7,13 @@
 import fileparse
 import stock
 import tableformat
+from portfolio import Portfolio
 
 def read_portfolio(filename):
     with open(filename) as f:
         portdicts = fileparse.parse_csv(f, select=['name', 'shares', 'price'], types=[str, int, float]) 
         portfolio = [ stock.Stock(d['name'], d['shares'], d['price']) for d in portdicts ]
-        return portfolio
+        return Portfolio(portfolio)
 
 
 def read_prices(filename):
@@ -35,17 +36,9 @@ def make_report(portfolio, prices):
 
 def print_report(reportdata, formatter):
      formatter.headings(['Name','Shares','Price','Change'])
-#     headers = ('Name', 'Shares', 'Price', 'Change')
-#     separator = '----------'
-#     print(f'{headers[0]:>10s} {headers[1]:>10s} {headers[2]:>10s} {headers[3]:>10s}')
-#     print(f'{separator:>10s} {separator:>10s} {separator:>10s} {separator:>10s}')
      for name, shares, price, change in reportdata:
         rowdata = [ name, str(shares), f'{price:0.2f}', f'{change:0.2f}']
         formatter.row(rowdata)
-#    currency_sym = '$'
-#    for name, shares, price, change in report:
-#        money = f'{currency_sym}{price:0.2f}'
-#        print(f'{name:>10s} {shares:>10d} {price:>10.2f} {change:>10.2f}')
 
 
 def portfolio_report(portfolio_filename, prices_filename, fmt='txt'):
 
@@ -1,5 +1,7 @@
 class Stock:
 
+    __slots__ = 'name', '_shares', 'price'
+
     def __init__(self, name, shares, price):
         self.name = name
         self.shares = shares
@@ -9,10 +11,23 @@ def __init__(self, name, shares, price):
     def __repr__(self):
         return f'Stock({self.name}, {self.shares}, {self.price})'
 
+    
+    @property
+    def shares(self):
+        return self._shares
+
+
+    @shares.setter
+    def shares(self, value):
+        if not isinstance(value, int):
+            raise TypeError('Expected int')
+        self._shares = value
+
 
     def sell(self, qty):
        self.shares -= qty 
 
 
+    @property
     def cost(self):
        return self.shares * self.price 
@@ -0,0 +1,55 @@
+# ticker.py
+
+from follow import follow
+import csv
+import report
+import tableformat
+
+def select_columns(rows, indices):
+    for row in rows:
+        yield [ row[index] for index in indices ]
+
+
+def convert_types(rows, types):
+    for row in rows:
+        yield [func(val) for func, val in zip(types, row)]
+
+
+def make_dicts(rows, headers):
+    for row in rows:
+        yield dict(zip(headers, row))
+
+
+def filter_symbols(rows, names):
+    for row in rows:
+        if row['name'] in names:
+            yield row
+
+
+def parse_stock_data(lines):
+    rows = csv.reader(lines)
+    rows = select_columns(rows, [0, 1, 4])
+    rows = convert_types(rows, [str, float, float])
+    rows = make_dicts(rows, ['name', 'price', 'change'])
+    return rows
+
+
+def ticker(portfile, logfile, fmt):
+    portfolio = report.read_portfolio(portfile)
+    lines = follow(logfile)
+    rows = parse_stock_data(lines)
+    rows = filter_symbols(rows, portfolio)
+    formatter = tableformat.create_formatter(fmt)
+    formatter.headings(['Name', 'Price', 'Change'])
+    for row in rows:
+        formatter.row([ row['name'], f"{row['price']:0.2f}", f"{row['change']:0.2f}"])
+
+
+
+if __name__ == '__main__':
+    
+    portfolio = report.read_portfolio('Data/portfolio.csv')
+    rows = parse_stock_data(follow('Data/stocklog.csv'))
+    rows = filter_symbols(rows, portfolio)
+    for row in rows:
+        print(row)