Mercurial > p > roundup > code
comparison PageTemplates/PythonExpr.py @ 984:a3a8ac7b8c40
Adding PageTemplates to the dist
| author | Richard Jones <richard@users.sourceforge.net> |
|---|---|
| date | Fri, 30 Aug 2002 08:27:34 +0000 |
| parents | |
| children |
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| 983:7fe79c67aaa9 | 984:a3a8ac7b8c40 |
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| 1 ############################################################################## | |
| 2 # | |
| 3 # Copyright (c) 2001 Zope Corporation and Contributors. All Rights Reserved. | |
| 4 # | |
| 5 # This software is subject to the provisions of the Zope Public License, | |
| 6 # Version 2.0 (ZPL). A copy of the ZPL should accompany this distribution. | |
| 7 # THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED | |
| 8 # WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED | |
| 9 # WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS | |
| 10 # FOR A PARTICULAR PURPOSE | |
| 11 # | |
| 12 ############################################################################## | |
| 13 | |
| 14 """Generic Python Expression Handler | |
| 15 """ | |
| 16 | |
| 17 __version__='$Revision: 1.1 $'[11:-2] | |
| 18 | |
| 19 from TALES import CompilerError | |
| 20 from string import strip, split, join, replace, lstrip | |
| 21 from sys import exc_info | |
| 22 | |
| 23 class getSecurityManager: | |
| 24 '''Null security manager''' | |
| 25 def validate(self, *args, **kwargs): | |
| 26 return 1 | |
| 27 addContext = removeContext = validateValue = validate | |
| 28 | |
| 29 class PythonExpr: | |
| 30 def __init__(self, name, expr, engine): | |
| 31 self.expr = expr = replace(strip(expr), '\n', ' ') | |
| 32 try: | |
| 33 d = {} | |
| 34 exec 'def f():\n return %s\n' % strip(expr) in d | |
| 35 self._f = d['f'] | |
| 36 except: | |
| 37 raise CompilerError, ('Python expression error:\n' | |
| 38 '%s: %s') % exc_info()[:2] | |
| 39 self._get_used_names() | |
| 40 | |
| 41 def _get_used_names(self): | |
| 42 self._f_varnames = vnames = [] | |
| 43 for vname in self._f.func_code.co_names: | |
| 44 if vname[0] not in '$_': | |
| 45 vnames.append(vname) | |
| 46 | |
| 47 def _bind_used_names(self, econtext): | |
| 48 # Bind template variables | |
| 49 names = {} | |
| 50 vars = econtext.vars | |
| 51 getType = econtext._engine.getTypes().get | |
| 52 for vname in self._f_varnames: | |
| 53 has, val = vars.has_get(vname) | |
| 54 if not has: | |
| 55 has = val = getType(vname) | |
| 56 if has: | |
| 57 val = ExprTypeProxy(vname, val, econtext) | |
| 58 if has: | |
| 59 names[vname] = val | |
| 60 return names | |
| 61 | |
| 62 def __call__(self, econtext): | |
| 63 __traceback_info__ = self.expr | |
| 64 f = self._f | |
| 65 f.func_globals.update(self._bind_used_names(econtext)) | |
| 66 return f() | |
| 67 | |
| 68 def __str__(self): | |
| 69 return 'Python expression "%s"' % self.expr | |
| 70 def __repr__(self): | |
| 71 return '<PythonExpr %s>' % self.expr | |
| 72 | |
| 73 class ExprTypeProxy: | |
| 74 '''Class that proxies access to an expression type handler''' | |
| 75 def __init__(self, name, handler, econtext): | |
| 76 self._name = name | |
| 77 self._handler = handler | |
| 78 self._econtext = econtext | |
| 79 def __call__(self, text): | |
| 80 return self._handler(self._name, text, | |
| 81 self._econtext._engine)(self._econtext) | |
| 82 |