# -*- coding: utf-8 -*- # # Copyright (C) 2006-2008 Edgewall Software # All rights reserved. # # This software is licensed as described in the file COPYING, which # you should have received as part of this distribution. The terms # are also available at http://genshi.edgewall.org/wiki/License. # # This software consists of voluntary contributions made by many # individuals. For the exact contribution history, see the revision # history and logs, available at http://genshi.edgewall.org/log/. """Plain text templating engine. This module implements two template language syntaxes, at least for a certain transitional period. `OldTextTemplate` (aliased to just `TextTemplate`) defines a syntax that was inspired by Cheetah/Velocity. `NewTextTemplate` on the other hand is inspired by the syntax of the Django template language, which has more explicit delimiting of directives, and is more flexible with regards to white space and line breaks. In a future release, `OldTextTemplate` will be phased out in favor of `NewTextTemplate`, as the names imply. Therefore the new syntax is strongly recommended for new projects, and existing projects may want to migrate to the new syntax to remain compatible with future Genshi releases. """ import re from genshi.core import TEXT from genshi.template.base import BadDirectiveError, Template, \ TemplateSyntaxError, EXEC, INCLUDE, SUB from genshi.template.eval import Suite from genshi.template.directives import * from genshi.template.directives import Directive from genshi.template.interpolation import interpolate __all__ = ['NewTextTemplate', 'OldTextTemplate', 'TextTemplate'] __docformat__ = 'restructuredtext en' class NewTextTemplate(Template): r"""Implementation of a simple text-based template engine. This class will replace `OldTextTemplate` in a future release. It uses a more explicit delimiting style for directives: instead of the old style which required putting directives on separate lines that were prefixed with a ``#`` sign, directives and commenbtsr are enclosed in delimiter pairs (by default ``{% ... %}`` and ``{# ... #}``, respectively). Variable substitution uses the same interpolation syntax as for markup languages: simple references are prefixed with a dollar sign, more complex expression enclosed in curly braces. >>> tmpl = NewTextTemplate('''Dear $name, ... ... {# This is a comment #} ... We have the following items for you: ... {% for item in items %} ... * ${'Item %d' % item} ... {% end %} ... ''') >>> print tmpl.generate(name='Joe', items=[1, 2, 3]).render() Dear Joe, We have the following items for you: * Item 1 * Item 2 * Item 3 By default, no spaces or line breaks are removed. If a line break should not be included in the output, prefix it with a backslash: >>> tmpl = NewTextTemplate('''Dear $name, ... ... {# This is a comment #}\ ... We have the following items for you: ... {% for item in items %}\ ... * $item ... {% end %}\ ... ''') >>> print tmpl.generate(name='Joe', items=[1, 2, 3]).render() Dear Joe, We have the following items for you: * 1 * 2 * 3 Backslashes are also used to escape the start delimiter of directives and comments: >>> tmpl = NewTextTemplate('''Dear $name, ... ... \{# This is a comment #} ... We have the following items for you: ... {% for item in items %}\ ... * $item ... {% end %}\ ... ''') >>> print tmpl.generate(name='Joe', items=[1, 2, 3]).render() Dear Joe, {# This is a comment #} We have the following items for you: * 1 * 2 * 3 :since: version 0.5 """ directives = [('def', DefDirective), ('when', WhenDirective), ('otherwise', OtherwiseDirective), ('for', ForDirective), ('if', IfDirective), ('choose', ChooseDirective), ('with', WithDirective)] serializer = 'text' _DIRECTIVE_RE = r'((? offset: text = _escape_sub(_escape_repl, source[offset:start]) for kind, data, pos in interpolate(text, self.filepath, lineno, lookup=self.lookup): stream.append((kind, data, pos)) lineno += len(text.splitlines()) lineno += len(source[start:end].splitlines()) command, value = mo.group(2, 3) if command == 'include': pos = (self.filename, lineno, 0) value = list(interpolate(value, self.filepath, lineno, 0, lookup=self.lookup)) if len(value) == 1 and value[0][0] is TEXT: value = value[0][1] stream.append((INCLUDE, (value, None, []), pos)) elif command == 'python': if not self.allow_exec: raise TemplateSyntaxError('Python code blocks not allowed', self.filepath, lineno) try: suite = Suite(value, self.filepath, lineno, lookup=self.lookup) except SyntaxError, err: raise TemplateSyntaxError(err, self.filepath, lineno + (err.lineno or 1) - 1) pos = (self.filename, lineno, 0) stream.append((EXEC, suite, pos)) elif command == 'end': depth -= 1 if depth in dirmap: directive, start_offset = dirmap.pop(depth) substream = stream[start_offset:] stream[start_offset:] = [(SUB, ([directive], substream), (self.filepath, lineno, 0))] elif command: cls = self._dir_by_name.get(command) if cls is None: raise BadDirectiveError(command) directive = cls, value, None, (self.filepath, lineno, 0) dirmap[depth] = (directive, len(stream)) depth += 1 offset = end if offset < len(source): text = _escape_sub(_escape_repl, source[offset:]) for kind, data, pos in interpolate(text, self.filepath, lineno, lookup=self.lookup): stream.append((kind, data, pos)) return stream class OldTextTemplate(Template): """Legacy implementation of the old syntax text-based templates. This class is provided in a transition phase for backwards compatibility. New code should use the `NewTextTemplate` class and the improved syntax it provides. >>> tmpl = OldTextTemplate('''Dear $name, ... ... We have the following items for you: ... #for item in items ... * $item ... #end ... ... All the best, ... Foobar''') >>> print tmpl.generate(name='Joe', items=[1, 2, 3]).render() Dear Joe, We have the following items for you: * 1 * 2 * 3 All the best, Foobar """ directives = [('def', DefDirective), ('when', WhenDirective), ('otherwise', OtherwiseDirective), ('for', ForDirective), ('if', IfDirective), ('choose', ChooseDirective), ('with', WithDirective)] serializer = 'text' _DIRECTIVE_RE = re.compile(r'(?:^[ \t]*(? offset: text = source[offset:start] for kind, data, pos in interpolate(text, self.filepath, lineno, lookup=self.lookup): stream.append((kind, data, pos)) lineno += len(text.splitlines()) text = source[start:end].lstrip()[1:] lineno += len(text.splitlines()) directive = text.split(None, 1) if len(directive) > 1: command, value = directive else: command, value = directive[0], None if command == 'end': depth -= 1 if depth in dirmap: directive, start_offset = dirmap.pop(depth) substream = stream[start_offset:] stream[start_offset:] = [(SUB, ([directive], substream), (self.filepath, lineno, 0))] elif command == 'include': pos = (self.filename, lineno, 0) stream.append((INCLUDE, (value.strip(), None, []), pos)) elif command != '#': cls = self._dir_by_name.get(command) if cls is None: raise BadDirectiveError(command) directive = cls, value, None, (self.filepath, lineno, 0) dirmap[depth] = (directive, len(stream)) depth += 1 offset = end if offset < len(source): text = source[offset:].replace('\\#', '#') for kind, data, pos in interpolate(text, self.filepath, lineno, lookup=self.lookup): stream.append((kind, data, pos)) return stream TextTemplate = OldTextTemplate