update from Atlas

metaprog/spreadsheet.py

@@ -0,0 +1,50 @@
+"""
+Spreadsheet example adapted from Raymond Hettinger's `recipe`__
+
+__ http://code.activestate.com/recipes/355045-spreadsheet/
+
+Demonstration::
+
+    >>> from math import sin, pi
+    >>> ss = Spreadsheet(sin=sin, pi=pi, abs=abs)
+    >>> ss['a1'] = '-5'
+    >>> ss['a2'] = 'a1*6'
+    >>> ss['a3'] = 'a2*7'
+    >>> ss['a3']
+    -210
+    >>> ss['b1'] = 'sin(pi/4)'
+    >>> ss['b1']  # doctest:+ELLIPSIS
+    0.707106781186...
+    >>> ss.getformula('b1')
+    'sin(pi/4)'
+    >>> ss['c1'] = 'abs(a2)'
+    >>> ss['c1']
+    30
+    >>> ss['c2'] = 'len(a2)'
+    >>> ss['c2']
+    Traceback (most recent call last):
+      ...
+    NameError: name 'len' is not defined
+    >>> ss['d1'] = '3*'
+    >>> ss['d1']
+    Traceback (most recent call last):
+      ...
+    SyntaxError: unexpected EOF while parsing
+"""
+
+
+class Spreadsheet:
+
+    def __init__(self, **tools):
+        self._cells = {}
+        self._tools = {'__builtins__' : {}}
+        self._tools.update(tools)
+
+    def __setitem__(self, key, formula):
+        self._cells[key] = formula
+
+    def getformula(self, key):
+        return self._cells[key]
+
+    def __getitem__(self, key):
+        return eval(self._cells[key], self._tools, self)

metaprog/spreadsheet2.py

@@ -0,0 +1,54 @@
+"""
+Spreadsheet example adapted from Raymond Hettinger's `recipe`__
+
+__ http://code.activestate.com/recipes/355045-spreadsheet/
+
+Demonstration::
+
+    >>> from math import sin, pi
+    >>> ss = Spreadsheet(sin=sin, pi=pi, abs=abs)
+    >>> ss['a1'] = '-5'
+    >>> ss['a2'] = 'a1*6'
+    >>> ss['a3'] = 'a2*7'
+    >>> ss['a3']
+    -210
+    >>> ss['b1'] = 'sin(pi/4)'
+    >>> ss['b1']  # doctest:+ELLIPSIS
+    0.707106781186...
+    >>> ss.getformula('b1')
+    'sin(pi/4)'
+    >>> ss['c1'] = 'abs(a2)'
+    >>> ss['c1']
+    30
+    >>> ss['c2'] = 'len(a2)'
+    >>> ss['c2']
+    Traceback (most recent call last):
+      ...
+    NameError: name 'len' is not defined
+    >>> ss['d1'] = '3*'
+    Traceback (most recent call last):
+      ...
+    SyntaxError: unexpected EOF while parsing ['d1'] = '3*'
+"""
+
+
+class Spreadsheet:
+
+    def __init__(self, **tools):
+        self._cells = {}
+        self._tools = {'__builtins__' : {}}
+        self._tools.update(tools)
+
+    def __setitem__(self, key, formula):
+        try:
+            compile(formula, '<__setitem__>', 'eval')
+        except SyntaxError as exc:
+            msg = '{} [{!r}] = {!r}'.format(exc.msg, key, formula)
+            raise SyntaxError(msg)
+        self._cells[key] = formula
+
+    def getformula(self, key):
+        return self._cells[key]
+
+    def __getitem__(self, key):
+        return eval(self._cells[key], self._tools, self)