371 lines
10 KiB
Python
371 lines
10 KiB
Python
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"""PyPlate : a simple Python-based templating program
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PyPlate parses a file and replaces directives (in double square brackets [[ ... ]])
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by various means using a given dictionary of variables. Arbitrary Python code
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can be run inside many of the directives, making this system highly flexible.
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Usage:
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# Load and parse template file
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template = pyplate.Template("output") (filename or string)
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# Execute it with a dictionary of variables
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template.execute_file(output_stream, locals())
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PyPlate defines the following directives:
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[[...]] evaluate the arbitrary Python expression and insert the
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result into the output
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[[# ... #]] comment.
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[[exec ...]] execute arbitrary Python code in the sandbox namespace
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[[if ...]] conditional expressions with usual Python semantics
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[[elif ...]]
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[[else]]
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[[end]]
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[[for ... in ...]] for-loop with usual Python semantics
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[[end]]
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[[def ...(...)]] define a "function" out of other templating elements
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[[end]]
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[[call ...]] call a templating function (not a regular Python function)
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"""
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#
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# Copyright (C) 2002 Michael Droettboom
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#
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# This program is free software; you can redistribute it and/or
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# modify it under the terms of the GNU General Public License
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# as published by the Free Software Foundation; either version 2
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# of the License, or (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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#
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from __future__ import nested_scopes
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import sys, string, re, io
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re_directive = re.compile("\[\[(.*)\]\]")
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re_for_loop = re.compile("for (.*) in (.*)")
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re_if = re.compile("if (.*)")
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re_elif = re.compile("elif (.*)")
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re_def = re.compile("def (.*?)\((.*)\)")
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re_call = re.compile("call (.*?)\((.*)\)")
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re_exec = re.compile("exec (.*)")
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re_comment = re.compile("#(.*)#")
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############################################################
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# Template parser
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class ParserException(Exception):
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def __init__(self, lineno, s):
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Exception.__init__(self, "line %d: %s" % (lineno, s))
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class Template:
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def __init__(self, filename=None):
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if filename != None:
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try:
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self.parse_file(filename)
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except:
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self.parse_string(filename)
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def parse_file(self, filename):
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file = open(filename, 'r')
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self.parse(file)
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file.close()
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def parse_string(self, template):
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if sys.version_info >= (3,0):
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file = io.StringIO(template)
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else:
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file = io.StringIO(template.decode('utf-8'))
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self.parse(file)
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file.close()
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def parse(self, file):
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self.file = file
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self.line = self.file.read()
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self.lineno = 0
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self.functions = {}
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self.tree = TopLevelTemplateNode(self)
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def parser_get(self):
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if self.line == '':
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return None
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return self.line
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def parser_eat(self, chars):
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self.lineno = self.lineno + self.line[:chars].count("\n")
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self.line = self.line[chars:]
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def parser_exception(self, s):
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raise ParserException(self.lineno, s)
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def execute_file(self, filename, data):
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file = open(filename, 'w')
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self.execute(file, data)
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file.close()
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def execute_string(self, data):
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s = io.StringIO()
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self.execute(s, data)
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return s.getvalue()
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def execute_stdout(self, data):
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self.execute(sys.stdout, data)
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def execute(self, stream=sys.stdout, data={}):
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self.tree.execute(stream, data)
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def __repr__(self):
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return repr(self.tree)
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############################################################
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# NODES
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class TemplateNode:
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def __init__(self, parent, s):
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self.parent = parent
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self.s = s
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self.node_list = []
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while 1:
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new_node = TemplateNodeFactory(parent)
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if self.add_node(new_node):
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break
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def add_node(self, node):
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if node == 'end':
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return 1
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elif node != None:
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self.node_list.append(node)
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else:
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raise self.parent.parser_exception(
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"[[%s]] does not have a matching [[end]]" % self.s)
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def execute(self, stream, data):
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for node in self.node_list:
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node.execute(stream, data)
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def __repr__(self):
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r = "<" + self.__class__.__name__ + " "
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for i in self.node_list:
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r = r + repr(i)
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r = r + ">"
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return r
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class TopLevelTemplateNode(TemplateNode):
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def __init__(self, parent):
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TemplateNode.__init__(self, parent, '')
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def add_node(self, node):
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if node != None:
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self.node_list.append(node)
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else:
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return 1
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class ForTemplateNode(TemplateNode):
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def __init__(self, parent, s):
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TemplateNode.__init__(self, parent, s)
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match = re_for_loop.match(s)
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if match == None:
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raise self.parent.parser_exception(
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"[[%s]] is not a valid for-loop expression" % self.s)
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else:
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self.vars_temp = match.group(1).split(",")
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self.vars = []
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for v in self.vars_temp:
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self.vars.append(v.strip())
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#print self.vars
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self.expression = match.group(2)
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def execute(self, stream, data):
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remember_vars = {}
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for var in self.vars:
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if var in data:
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remember_vars[var] = data[var]
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for list in eval(self.expression, globals(), data):
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if is_sequence(list):
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for index, value in enumerate(list):
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data[self.vars[index]] = value
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else:
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data[self.vars[0]] = list
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TemplateNode.execute(self, stream, data)
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for key, value in remember_vars.items():
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data[key] = value
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class IfTemplateNode(TemplateNode):
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def __init__(self, parent, s):
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self.else_node = None
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TemplateNode.__init__(self, parent, s)
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match = re_if.match(s)
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if match == None:
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raise self.parent.parser_exception(
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"[[%s]] is not a valid if expression" % self.s)
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else:
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self.expression = match.group(1)
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def add_node(self, node):
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if node == 'end':
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return 1
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elif isinstance(node, ElseTemplateNode):
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self.else_node = node
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return 1
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elif isinstance(node, ElifTemplateNode):
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self.else_node = node
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return 1
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elif node != None:
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self.node_list.append(node)
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else:
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raise self.parent.parser_exception(
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"[[%s]] does not have a matching [[end]]" % self.s)
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def execute(self, stream, data):
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if eval(self.expression, globals(), data):
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TemplateNode.execute(self, stream, data)
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elif self.else_node != None:
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self.else_node.execute(stream, data)
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class ElifTemplateNode(IfTemplateNode):
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def __init__(self, parent, s):
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self.else_node = None
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TemplateNode.__init__(self, parent, s)
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match = re_elif.match(s)
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if match == None:
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self.parent.parser_exception(
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"[[%s]] is not a valid elif expression" % self.s)
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else:
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self.expression = match.group(1)
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class ElseTemplateNode(TemplateNode):
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pass
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class FunctionTemplateNode(TemplateNode):
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def __init__(self, parent, s):
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TemplateNode.__init__(self, parent, s)
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match = re_def.match(s)
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if match == None:
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self.parent.parser_exception(
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"[[%s]] is not a valid function definition" % self.s)
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self.function_name = match.group(1)
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self.vars_temp = match.group(2).split(",")
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self.vars = []
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for v in self.vars_temp:
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self.vars.append(v.strip())
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#print self.vars
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self.parent.functions[self.function_name] = self
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def execute(self, stream, data):
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pass
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def call(self, args, stream, data):
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remember_vars = {}
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for index, var in enumerate(self.vars):
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if var in data:
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remember_vars[var] = data[var]
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data[var] = args[index]
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TemplateNode.execute(self, stream, data)
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for key, value in remember_vars.items():
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data[key] = value
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class LeafTemplateNode(TemplateNode):
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def __init__(self, parent, s):
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self.parent = parent
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self.s = s
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def execute(self, stream, data):
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stream.write(self.s)
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def __repr__(self):
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return "<" + self.__class__.__name__ + ">"
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class CommentTemplateNode(LeafTemplateNode):
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def execute(self, stream, data):
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pass
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class ExpressionTemplateNode(LeafTemplateNode):
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def execute(self, stream, data):
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if sys.version_info >= (3,0):
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stream.write(str(eval(self.s, globals(), data)))
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else:
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stream.write(str(eval(self.s, globals(), data)).decode('utf-8'))
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class ExecTemplateNode(LeafTemplateNode):
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def __init__(self, parent, s):
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LeafTemplateNode.__init__(self, parent, s)
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match = re_exec.match(s)
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if match == None:
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self.parent.parser_exception(
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"[[%s]] is not a valid statement" % self.s)
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self.s = match.group(1)
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def execute(self, stream, data):
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exec(self.s, globals(), data)
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pass
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class CallTemplateNode(LeafTemplateNode):
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def __init__(self, parent, s):
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LeafTemplateNode.__init__(self, parent, s)
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match = re_call.match(s)
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if match == None:
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self.parent.parser_exception(
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"[[%s]] is not a valid function call" % self.s)
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self.function_name = match.group(1)
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self.vars = "(" + match.group(2).strip() + ",)"
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def execute(self, stream, data):
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self.parent.functions[self.function_name].call(
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eval(self.vars, globals(), data), stream, data)
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############################################################
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# Node factory
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template_factory_type_map = {
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'if' : IfTemplateNode,
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'for' : ForTemplateNode,
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'elif' : ElifTemplateNode,
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'else' : ElseTemplateNode,
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'def' : FunctionTemplateNode,
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'call' : CallTemplateNode,
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'exec' : ExecTemplateNode }
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template_factory_types = template_factory_type_map.keys()
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def TemplateNodeFactory(parent):
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src = parent.parser_get()
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if src == None:
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return None
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match = re_directive.search(src)
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if match == None:
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parent.parser_eat(len(src))
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return LeafTemplateNode(parent, src)
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elif src == '' or match.start() != 0:
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parent.parser_eat(match.start())
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return LeafTemplateNode(parent, src[:match.start()])
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else:
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directive = match.group()[2:-2].strip()
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parent.parser_eat(match.end())
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if directive == 'end':
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return 'end'
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elif re_comment.match(directive):
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return CommentTemplateNode(parent, directive)
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else:
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for i in template_factory_types:
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if directive[0:len(i)] == i:
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return template_factory_type_map[i](parent, directive)
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return ExpressionTemplateNode(parent, directive)
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def is_sequence(object):
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try:
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test = object[0:0]
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except:
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return False
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else:
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return True
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