# Copyright 2012 Benjamin Kalman
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# TODO: Escaping control characters somehow. e.g. \{{, \{{-.
import json
import re
'''Motemplate templates are data binding templates more-than-loosely inspired by
ctemplate. Use like:
from motemplate import Motemplate
template = Motemplate('hello {{#foo bar/}} world')
input = {
'foo': [
{ 'bar': 1 },
{ 'bar': 2 },
{ 'bar': 3 }
]
}
print(template.render(input).text)
Motemplate will use get() on contexts to return values, so to create custom
getters (for example, something that populates values lazily from keys), just
provide an object with a get() method.
class CustomContext(object):
def get(self, key):
return 10
print(Motemplate('hello {{world}}').render(CustomContext()).text)
will print 'hello 10'.
'''
class ParseException(Exception):
'''The exception thrown while parsing a template.
'''
def __init__(self, error):
Exception.__init__(self, error)
class RenderResult(object):
'''The result of a render operation.
'''
def __init__(self, text, errors):
self.text = text;
self.errors = errors
def __repr__(self):
return '%s(text=%s, errors=%s)' % (type(self).__name__,
self.text,
self.errors)
def __str__(self):
return repr(self)
class _StringBuilder(object):
'''Efficiently builds strings.
'''
def __init__(self):
self._buf = []
def __len__(self):
self._Collapse()
return len(self._buf[0])
def Append(self, string):
if not isinstance(string, basestring):
string = str(string)
self._buf.append(string)
def ToString(self):
self._Collapse()
return self._buf[0]
def _Collapse(self):
self._buf = [u''.join(self._buf)]
def __repr__(self):
return self.ToString()
def __str__(self):
return repr(self)
class _Contexts(object):
'''Tracks a stack of context objects, providing efficient key/value retrieval.
'''
class _Node(object):
'''A node within the stack. Wraps a real context and maintains the key/value
pairs seen so far.
'''
def __init__(self, value):
self._value = value
self._value_has_get = hasattr(value, 'get')
self._found = {}
def GetKeys(self):
'''Returns the list of keys that |_value| contains.
'''
return self._found.keys()
def Get(self, key):
'''Returns the value for |key|, or None if not found (including if
|_value| doesn't support key retrieval).
'''
if not self._value_has_get:
return None
value = self._found.get(key)
if value is not None:
return value
value = self._value.get(key)
if value is not None:
self._found[key] = value
return value
def __repr__(self):
return 'Node(value=%s, found=%s)' % (self._value, self._found)
def __str__(self):
return repr(self)
def __init__(self, globals_):
'''Initializes with the initial global contexts, listed in order from most
to least important.
'''
self._nodes = map(_Contexts._Node, globals_)
self._first_local = len(self._nodes)
self._value_info = {}
def CreateFromGlobals(self):
new = _Contexts([])
new._nodes = self._nodes[:self._first_local]
new._first_local = self._first_local
return new
def Push(self, context):
self._nodes.append(_Contexts._Node(context))
def Pop(self):
node = self._nodes.pop()
assert len(self._nodes) >= self._first_local
for found_key in node.GetKeys():
# [0] is the stack of nodes that |found_key| has been found in.
self._value_info[found_key][0].pop()
def FirstLocal(self):
if len(self._nodes) == self._first_local:
return None
return self._nodes[-1]._value
def Resolve(self, path):
# This method is only efficient at finding |key|; if |tail| has a value (and
# |key| evaluates to an indexable value) we'll need to descend into that.
key, tail = path.split('.', 1) if '.' in path else (path, None)
found = self._FindNodeValue(key)
if tail is None:
return found
for part in tail.split('.'):
if not hasattr(found, 'get'):
return None
found = found.get(part)
return found
def Scope(self, context, fn, *args):
self.Push(context)
try:
return fn(*args)
finally:
self.Pop()
def _FindNodeValue(self, key):
# |found_node_list| will be all the nodes that |key| has been found in.
# |checked_node_set| are those that have been checked.
info = self._value_info.get(key)
if info is None:
info = ([], set())
self._value_info[key] = info
found_node_list, checked_node_set = info
# Check all the nodes not yet checked for |key|.
newly_found = []
for node in reversed(self._nodes):
if node in checked_node_set:
break
value = node.Get(key)
if value is not None:
newly_found.append(node)
checked_node_set.add(node)
# The nodes will have been found in reverse stack order. After extending
# the found nodes, the freshest value will be at the tip of the stack.
found_node_list.extend(reversed(newly_found))
if not found_node_list:
return None
return found_node_list[-1]._value.get(key)
class _Stack(object):
class Entry(object):
def __init__(self, name, id_):
self.name = name
self.id_ = id_
def __init__(self, entries=[]):
self.entries = entries
def Descend(self, name, id_):
descended = list(self.entries)
descended.append(_Stack.Entry(name, id_))
return _Stack(entries=descended)
class _InternalContext(object):
def __init__(self):
self._render_state = None
def SetRenderState(self, render_state):
self._render_state = render_state
def get(self, key):
if key == 'errors':
errors = self._render_state._errors
return '\n'.join(errors) if errors else None
return None
class _RenderState(object):
'''The state of a render call.
'''
def __init__(self, name, contexts, _stack=_Stack()):
self.text = _StringBuilder()
self.contexts = contexts
self._name = name
self._errors = []
self._stack = _stack
def AddResolutionError(self, id_, description=None):
message = id_.CreateResolutionErrorMessage(self._name, stack=self._stack)
if description is not None:
message = '%s (%s)' % (message, description)
self._errors.append(message)
def Copy(self):
return _RenderState(
self._name, self.contexts, _stack=self._stack)
def ForkPartial(self, custom_name, id_):
name = custom_name or id_.name
return _RenderState(name,
self.contexts.CreateFromGlobals(),
_stack=self._stack.Descend(name, id_))
def Merge(self, render_state, text_transform=None):
self._errors.extend(render_state._errors)
text = render_state.text.ToString()
if text_transform is not None:
text = text_transform(text)
self.text.Append(text)
def GetResult(self):
return RenderResult(self.text.ToString(), self._errors);
class _Identifier(object):
'''An identifier of the form 'foo', 'foo.bar.baz', 'foo-bar.baz', etc.
'''
_VALID_ID_MATCHER = re.compile(r'^[a-zA-Z0-9@_/-]+$')
def __init__(self, name, line, column):
self.name = name
self.line = line
self.column = column
if name == '':
raise ParseException('Empty identifier %s' % self.GetDescription())
for part in name.split('.'):
if not _Identifier._VALID_ID_MATCHER.match(part):
raise ParseException('Invalid identifier %s' % self.GetDescription())
def GetDescription(self):
return '\'%s\' at line %s column %s' % (self.name, self.line, self.column)
def CreateResolutionErrorMessage(self, name, stack=None):
message = _StringBuilder()
message.Append('Failed to resolve %s in %s\n' % (self.GetDescription(),
name))
if stack is not None:
for entry in reversed(stack.entries):
message.Append(' included as %s in %s\n' % (entry.id_.GetDescription(),
entry.name))
return message.ToString().strip()
def __repr__(self):
return self.name
def __str__(self):
return repr(self)
class _Node(object): pass
class _LeafNode(_Node):
def __init__(self, start_line, end_line):
self._start_line = start_line
self._end_line = end_line
def StartsWithNewLine(self):
return False
def TrimStartingNewLine(self):
pass
def TrimEndingSpaces(self):
return 0
def TrimEndingNewLine(self):
pass
def EndsWithEmptyLine(self):
return False
def GetStartLine(self):
return self._start_line
def GetEndLine(self):
return self._end_line
def __str__(self):
return repr(self)
class _DecoratorNode(_Node):
def __init__(self, content):
self._content = content
def StartsWithNewLine(self):
return self._content.StartsWithNewLine()
def TrimStartingNewLine(self):
self._content.TrimStartingNewLine()
def TrimEndingSpaces(self):
return self._content.TrimEndingSpaces()
def TrimEndingNewLine(self):
self._content.TrimEndingNewLine()
def EndsWithEmptyLine(self):
return self._content.EndsWithEmptyLine()
def GetStartLine(self):
return self._content.GetStartLine()
def GetEndLine(self):
return self._content.GetEndLine()
def __repr__(self):
return str(self._content)
def __str__(self):
return repr(self)
class _InlineNode(_DecoratorNode):
def __init__(self, content):
_DecoratorNode.__init__(self, content)
def Render(self, render_state):
content_render_state = render_state.Copy()
self._content.Render(content_render_state)
render_state.Merge(content_render_state,
text_transform=lambda text: text.replace('\n', ''))
class _IndentedNode(_DecoratorNode):
def __init__(self, content, indentation):
_DecoratorNode.__init__(self, content)
self._indent_str = ' ' * indentation
def Render(self, render_state):
if isinstance(self._content, _CommentNode):
return
def inlinify(text):
if len(text) == 0: # avoid rendering a blank line
return ''
buf = _StringBuilder()
buf.Append(self._indent_str)
buf.Append(text.replace('\n', '\n%s' % self._indent_str))
if not text.endswith('\n'): # partials will often already end in a \n
buf.Append('\n')
return buf.ToString()
content_render_state = render_state.Copy()
self._content.Render(content_render_state)
render_state.Merge(content_render_state, text_transform=inlinify)
class _BlockNode(_DecoratorNode):
def __init__(self, content):
_DecoratorNode.__init__(self, content)
content.TrimStartingNewLine()
content.TrimEndingSpaces()
def Render(self, render_state):
self._content.Render(render_state)
class _NodeCollection(_Node):
def __init__(self, nodes):
assert nodes
self._nodes = nodes
def Render(self, render_state):
for node in self._nodes:
node.Render(render_state)
def StartsWithNewLine(self):
return self._nodes[0].StartsWithNewLine()
def TrimStartingNewLine(self):
self._nodes[0].TrimStartingNewLine()
def TrimEndingSpaces(self):
return self._nodes[-1].TrimEndingSpaces()
def TrimEndingNewLine(self):
self._nodes[-1].TrimEndingNewLine()
def EndsWithEmptyLine(self):
return self._nodes[-1].EndsWithEmptyLine()
def GetStartLine(self):
return self._nodes[0].GetStartLine()
def GetEndLine(self):
return self._nodes[-1].GetEndLine()
def __repr__(self):
return ''.join(str(node) for node in self._nodes)
class _StringNode(_Node):
'''Just a string.
'''
def __init__(self, string, start_line, end_line):
self._string = string
self._start_line = start_line
self._end_line = end_line
def Render(self, render_state):
render_state.text.Append(self._string)
def StartsWithNewLine(self):
return self._string.startswith('\n')
def TrimStartingNewLine(self):
if self.StartsWithNewLine():
self._string = self._string[1:]
def TrimEndingSpaces(self):
original_length = len(self._string)
self._string = self._string[:self._LastIndexOfSpaces()]
return original_length - len(self._string)
def TrimEndingNewLine(self):
if self._string.endswith('\n'):
self._string = self._string[:len(self._string) - 1]
def EndsWithEmptyLine(self):
index = self._LastIndexOfSpaces()
return index == 0 or self._string[index - 1] == '\n'
def _LastIndexOfSpaces(self):
index = len(self._string)
while index > 0 and self._string[index - 1] == ' ':
index -= 1
return index
def GetStartLine(self):
return self._start_line
def GetEndLine(self):
return self._end_line
def __repr__(self):
return self._string
class _EscapedVariableNode(_LeafNode):
'''{{foo}}
'''
def __init__(self, id_):
_LeafNode.__init__(self, id_.line, id_.line)
self._id = id_
def Render(self, render_state):
value = render_state.contexts.Resolve(self._id.name)
if value is None:
render_state.AddResolutionError(self._id)
return
string = value if isinstance(value, basestring) else str(value)
render_state.text.Append(string.replace('&', '&')
.replace('<', '<')
.replace('>', '>'))
def __repr__(self):
return '{{%s}}' % self._id
class _UnescapedVariableNode(_LeafNode):
'''{{{foo}}}
'''
def __init__(self, id_):
_LeafNode.__init__(self, id_.line, id_.line)
self._id = id_
def Render(self, render_state):
value = render_state.contexts.Resolve(self._id.name)
if value is None:
render_state.AddResolutionError(self._id)
return
string = value if isinstance(value, basestring) else str(value)
render_state.text.Append(string)
def __repr__(self):
return '{{{%s}}}' % self._id
class _CommentNode(_LeafNode):
'''{{- This is a comment -}}
An empty placeholder node for correct indented rendering behaviour.
'''
def __init__(self, start_line, end_line):
_LeafNode.__init__(self, start_line, end_line)
def Render(self, render_state):
pass
def __repr__(self):
return '<comment>'
class _SectionNode(_DecoratorNode):
'''{{#var:foo}} ... {{/foo}}
'''
def __init__(self, bind_to, id_, content):
_DecoratorNode.__init__(self, content)
self._bind_to = bind_to
self._id = id_
def Render(self, render_state):
value = render_state.contexts.Resolve(self._id.name)
if isinstance(value, list):
for item in value:
if self._bind_to is not None:
render_state.contexts.Scope({self._bind_to.name: item},
self._content.Render, render_state)
else:
self._content.Render(render_state)
elif hasattr(value, 'get'):
if self._bind_to is not None:
render_state.contexts.Scope({self._bind_to.name: value},
self._content.Render, render_state)
else:
render_state.contexts.Scope(value, self._content.Render, render_state)
else:
render_state.AddResolutionError(self._id)
def __repr__(self):
return '{{#%s}}%s{{/%s}}' % (
self._id, _DecoratorNode.__repr__(self), self._id)
class _VertedSectionNode(_DecoratorNode):
'''{{?var:foo}} ... {{/foo}}
'''
def __init__(self, bind_to, id_, content):
_DecoratorNode.__init__(self, content)
self._bind_to = bind_to
self._id = id_
def Render(self, render_state):
value = render_state.contexts.Resolve(self._id.name)
if _VertedSectionNode.ShouldRender(value):
if self._bind_to is not None:
render_state.contexts.Scope({self._bind_to.name: value},
self._content.Render, render_state)
else:
self._content.Render(render_state)
def __repr__(self):
return '{{?%s}}%s{{/%s}}' % (
self._id, _DecoratorNode.__repr__(self), self._id)
@staticmethod
def ShouldRender(value):
if value is None:
return False
if isinstance(value, bool):
return value
if isinstance(value, list):
return len(value) > 0
return True
class _InvertedSectionNode(_DecoratorNode):
'''{{^foo}} ... {{/foo}}
'''
def __init__(self, bind_to, id_, content):
_DecoratorNode.__init__(self, content)
if bind_to is not None:
raise ParseException('{{^%s:%s}} does not support variable binding'
% (bind_to, id_))
self._id = id_
def Render(self, render_state):
value = render_state.contexts.Resolve(self._id.name)
if not _VertedSectionNode.ShouldRender(value):
self._content.Render(render_state)
def __repr__(self):
return '{{^%s}}%s{{/%s}}' % (
self._id, _DecoratorNode.__repr__(self), self._id)
class _AssertionNode(_LeafNode):
'''{{!foo Some comment about foo}}
'''
def __init__(self, id_, description):
_LeafNode.__init__(self, id_.line, id_.line)
self._id = id_
self._description = description
def Render(self, render_state):
if render_state.contexts.Resolve(self._id.name) is None:
render_state.AddResolutionError(self._id, description=self._description)
def __repr__(self):
return '{{!%s %s}}' % (self._id, self._description)
class _JsonNode(_LeafNode):
'''{{*foo}}
'''
def __init__(self, id_):
_LeafNode.__init__(self, id_.line, id_.line)
self._id = id_
def Render(self, render_state):
value = render_state.contexts.Resolve(self._id.name)
if value is None:
render_state.AddResolutionError(self._id)
return
render_state.text.Append(json.dumps(value, separators=(',',':')))
def __repr__(self):
return '{{*%s}}' % self._id
class _PartialNodeWithArguments(_DecoratorNode):
def __init__(self, partial, args):
if isinstance(partial, Motemplate):
# Preserve any get() method that the caller has added.
if hasattr(partial, 'get'):
self.get = partial.get
partial = partial._top_node
_DecoratorNode.__init__(self, partial)
self._partial = partial
self._args = args
def Render(self, render_state):
render_state.contexts.Scope(self._args, self._partial.Render, render_state)
class _PartialNodeInContext(_DecoratorNode):
def __init__(self, partial, context):
if isinstance(partial, Motemplate):
# Preserve any get() method that the caller has added.
if hasattr(partial, 'get'):
self.get = partial.get
partial = partial._top_node
_DecoratorNode.__init__(self, partial)
self._partial = partial
self._context = context
def Render(self, render_state):
original_contexts = render_state.contexts
try:
render_state.contexts = self._context
render_state.contexts.Scope(
# The first local context of |original_contexts| will be the
# arguments that were passed to the partial, if any.
original_contexts.FirstLocal() or {},
self._partial.Render, render_state)
finally:
render_state.contexts = original_contexts
class _PartialNode(_LeafNode):
'''{{+var:foo}} ... {{/foo}}
'''
def __init__(self, bind_to, id_, content):
_LeafNode.__init__(self, id_.line, id_.line)
self._bind_to = bind_to
self._id = id_
self._content = content
self._args = None
self._pass_through_id = None
@classmethod
def Inline(cls, id_):
return cls(None, id_, None)
def Render(self, render_state):
value = render_state.contexts.Resolve(self._id.name)
if value is None:
render_state.AddResolutionError(self._id)
return
if not isinstance(value, (Motemplate, _Node)):
render_state.AddResolutionError(self._id, description='not a partial')
return
if isinstance(value, Motemplate):
node, name = value._top_node, value._name
else:
node, name = value, None
partial_render_state = render_state.ForkPartial(name, self._id)
arg_context = {}
if self._pass_through_id is not None:
context = render_state.contexts.Resolve(self._pass_through_id.name)
if context is not None:
arg_context[self._pass_through_id.name] = context
if self._args is not None:
def resolve_args(args):
resolved = {}
for key, value in args.iteritems():
if isinstance(value, dict):
assert len(value.keys()) == 1
id_of_partial, partial_args = value.items()[0]
partial = render_state.contexts.Resolve(id_of_partial.name)
if partial is not None:
resolved[key] = _PartialNodeWithArguments(
partial, resolve_args(partial_args))
else:
context = render_state.contexts.Resolve(value.name)
if context is not None:
resolved[key] = context
return resolved
arg_context.update(resolve_args(self._args))
if self._bind_to and self._content:
arg_context[self._bind_to.name] = _PartialNodeInContext(
self._content, render_state.contexts)
if arg_context:
partial_render_state.contexts.Push(arg_context)
node.Render(partial_render_state)
render_state.Merge(
partial_render_state,
text_transform=lambda text: text[:-1] if text.endswith('\n') else text)
def SetArguments(self, args):
self._args = args
def PassThroughArgument(self, id_):
self._pass_through_id = id_
def __repr__(self):
return '{{+%s}}' % self._id
_TOKENS = {}
class _Token(object):
'''The tokens that can appear in a template.
'''
class Data(object):
def __init__(self, name, text, clazz):
self.name = name
self.text = text
self.clazz = clazz
_TOKENS[text] = self
def ElseNodeClass(self):
if self.clazz == _VertedSectionNode:
return _InvertedSectionNode
if self.clazz == _InvertedSectionNode:
return _VertedSectionNode
return None
def __repr__(self):
return self.name
def __str__(self):
return repr(self)
OPEN_START_SECTION = Data(
'OPEN_START_SECTION' , '{{#', _SectionNode)
OPEN_START_VERTED_SECTION = Data(
'OPEN_START_VERTED_SECTION' , '{{?', _VertedSectionNode)
OPEN_START_INVERTED_SECTION = Data(
'OPEN_START_INVERTED_SECTION', '{{^', _InvertedSectionNode)
OPEN_ASSERTION = Data(
'OPEN_ASSERTION' , '{{!', _AssertionNode)
OPEN_JSON = Data(
'OPEN_JSON' , '{{*', _JsonNode)
OPEN_PARTIAL = Data(
'OPEN_PARTIAL' , '{{+', _PartialNode)
OPEN_ELSE = Data(
'OPEN_ELSE' , '{{:', None)
OPEN_END_SECTION = Data(
'OPEN_END_SECTION' , '{{/', None)
INLINE_END_SECTION = Data(
'INLINE_END_SECTION' , '/}}', None)
OPEN_UNESCAPED_VARIABLE = Data(
'OPEN_UNESCAPED_VARIABLE' , '{{{', _UnescapedVariableNode)
CLOSE_MUSTACHE3 = Data(
'CLOSE_MUSTACHE3' , '}}}', None)
OPEN_COMMENT = Data(
'OPEN_COMMENT' , '{{-', _CommentNode)
CLOSE_COMMENT = Data(
'CLOSE_COMMENT' , '-}}', None)
OPEN_VARIABLE = Data(
'OPEN_VARIABLE' , '{{' , _EscapedVariableNode)
CLOSE_MUSTACHE = Data(
'CLOSE_MUSTACHE' , '}}' , None)
CHARACTER = Data(
'CHARACTER' , '.' , None)
class _TokenStream(object):
'''Tokeniser for template parsing.
'''
def __init__(self, string):
self.next_token = None
self.next_line = 1
self.next_column = 0
self._string = string
self._cursor = 0
self.Advance()
def HasNext(self):
return self.next_token is not None
def NextCharacter(self):
if self.next_token is _Token.CHARACTER:
return self._string[self._cursor - 1]
return None
def Advance(self):
if self._cursor > 0 and self._string[self._cursor - 1] == '\n':
self.next_line += 1
self.next_column = 0
elif self.next_token is not None:
self.next_column += len(self.next_token.text)
self.next_token = None
if self._cursor == len(self._string):
return None
assert self._cursor < len(self._string)
if (self._cursor + 1 < len(self._string) and
self._string[self._cursor + 1] in '{}'):
self.next_token = (
_TOKENS.get(self._string[self._cursor:self._cursor+3]) or
_TOKENS.get(self._string[self._cursor:self._cursor+2]))
if self.next_token is None:
self.next_token = _Token.CHARACTER
self._cursor += len(self.next_token.text)
return self
def AdvanceOver(self, token, description=None):
parse_error = None
if not self.next_token:
parse_error = 'Reached EOF but expected %s' % token.name
elif self.next_token is not token:
parse_error = 'Expecting token %s but got %s at line %s' % (
token.name, self.next_token.name, self.next_line)
if parse_error:
parse_error += ' %s' % description or ''
raise ParseException(parse_error)
return self.Advance()
def AdvanceOverSeparator(self, char, description=None):
self.SkipWhitespace()
next_char = self.NextCharacter()
if next_char != char:
parse_error = 'Expected \'%s\'. got \'%s\'' % (char, next_char)
if description is not None:
parse_error += ' (%s)' % description
raise ParseException(parse_error)
self.AdvanceOver(_Token.CHARACTER)
self.SkipWhitespace()
def AdvanceOverNextString(self, excluded=''):
start = self._cursor - len(self.next_token.text)
while (self.next_token is _Token.CHARACTER and
# Can use -1 here because token length of CHARACTER is 1.
self._string[self._cursor - 1] not in excluded):
self.Advance()
end = self._cursor - (len(self.next_token.text) if self.next_token else 0)
return self._string[start:end]
def AdvanceToNextWhitespace(self):
return self.AdvanceOverNextString(excluded=' \n\r\t')
def SkipWhitespace(self):
while (self.next_token is _Token.CHARACTER and
# Can use -1 here because token length of CHARACTER is 1.
self._string[self._cursor - 1] in ' \n\r\t'):
self.Advance()
def __repr__(self):
return '%s(next_token=%s, remainder=%s)' % (type(self).__name__,
self.next_token,
self._string[self._cursor:])
def __str__(self):
return repr(self)
class Motemplate(object):
'''A motemplate template.
'''
def __init__(self, template, name=None):
self.source = template
self._name = name
tokens = _TokenStream(template)
self._top_node = self._ParseSection(tokens)
if not self._top_node:
raise ParseException('Template is empty')
if tokens.HasNext():
raise ParseException('There are still tokens remaining at %s, '
'was there an end-section without a start-section?' %
tokens.next_line)
def _ParseSection(self, tokens):
nodes = []
while tokens.HasNext():
if tokens.next_token in (_Token.OPEN_END_SECTION,
_Token.OPEN_ELSE):
# Handled after running parseSection within the SECTION cases, so this
# is a terminating condition. If there *is* an orphaned
# OPEN_END_SECTION, it will be caught by noticing that there are
# leftover tokens after termination.
break
elif tokens.next_token in (_Token.CLOSE_MUSTACHE,
_Token.CLOSE_MUSTACHE3):
raise ParseException('Orphaned %s at line %s' % (tokens.next_token.name,
tokens.next_line))
nodes += self._ParseNextOpenToken(tokens)
for i, node in enumerate(nodes):
if isinstance(node, _StringNode):
continue
previous_node = nodes[i - 1] if i > 0 else None
next_node = nodes[i + 1] if i < len(nodes) - 1 else None
rendered_node = None
if node.GetStartLine() != node.GetEndLine():
rendered_node = _BlockNode(node)
if previous_node:
previous_node.TrimEndingSpaces()
if next_node:
next_node.TrimStartingNewLine()
elif ((not previous_node or previous_node.EndsWithEmptyLine()) and
(not next_node or next_node.StartsWithNewLine())):
indentation = 0
if previous_node:
indentation = previous_node.TrimEndingSpaces()
if next_node:
next_node.TrimStartingNewLine()
rendered_node = _IndentedNode(node, indentation)
else:
rendered_node = _InlineNode(node)
nodes[i] = rendered_node
if len(nodes) == 0:
return None
if len(nodes) == 1:
return nodes[0]
return _NodeCollection(nodes)
def _ParseNextOpenToken(self, tokens):
next_token = tokens.next_token
if next_token is _Token.CHARACTER:
# Plain strings.
start_line = tokens.next_line
string = tokens.AdvanceOverNextString()
return [_StringNode(string, start_line, tokens.next_line)]
elif next_token in (_Token.OPEN_VARIABLE,
_Token.OPEN_UNESCAPED_VARIABLE,
_Token.OPEN_JSON):
# Inline nodes that don't take arguments.
tokens.Advance()
close_token = (_Token.CLOSE_MUSTACHE3
if next_token is _Token.OPEN_UNESCAPED_VARIABLE else
_Token.CLOSE_MUSTACHE)
id_ = self._NextIdentifier(tokens)
tokens.AdvanceOver(close_token)
return [next_token.clazz(id_)]
elif next_token is _Token.OPEN_ASSERTION:
# Inline nodes that take arguments.
tokens.Advance()
id_ = self._NextIdentifier(tokens)
node = next_token.clazz(id_, tokens.AdvanceOverNextString())
tokens.AdvanceOver(_Token.CLOSE_MUSTACHE)
return [node]
elif next_token in (_Token.OPEN_PARTIAL,
_Token.OPEN_START_SECTION,
_Token.OPEN_START_VERTED_SECTION,
_Token.OPEN_START_INVERTED_SECTION):
# Block nodes, though they may have inline syntax like {{#foo bar /}}.
tokens.Advance()
bind_to, id_ = None, self._NextIdentifier(tokens)
if tokens.NextCharacter() == ':':
# This section has the format {{#bound:id}} as opposed to just {{id}}.
# That is, |id_| is actually the identifier to bind what the section
# is producing, not the identifier of where to find that content.
tokens.AdvanceOverSeparator(':')
bind_to, id_ = id_, self._NextIdentifier(tokens)
partial_args = None
if next_token is _Token.OPEN_PARTIAL:
partial_args = self._ParsePartialNodeArgs(tokens)
if tokens.next_token is not _Token.CLOSE_MUSTACHE:
# Inline syntax for partial types.
if bind_to is not None:
raise ParseException(
'Cannot bind %s to a self-closing partial' % bind_to)
tokens.AdvanceOver(_Token.INLINE_END_SECTION)
partial_node = _PartialNode.Inline(id_)
partial_node.SetArguments(partial_args)
return [partial_node]
elif tokens.next_token is not _Token.CLOSE_MUSTACHE:
# Inline syntax for non-partial types. Support select node types:
# variables, partials, JSON.
line, column = tokens.next_line, (tokens.next_column + 1)
name = tokens.AdvanceToNextWhitespace()
clazz = _UnescapedVariableNode
if name.startswith('*'):
clazz = _JsonNode
elif name.startswith('+'):
clazz = _PartialNode.Inline
if clazz is not _UnescapedVariableNode:
name = name[1:]
column += 1
inline_node = clazz(_Identifier(name, line, column))
if isinstance(inline_node, _PartialNode):
inline_node.SetArguments(self._ParsePartialNodeArgs(tokens))
if bind_to is not None:
inline_node.PassThroughArgument(bind_to)
tokens.SkipWhitespace()
tokens.AdvanceOver(_Token.INLINE_END_SECTION)
return [next_token.clazz(bind_to, id_, inline_node)]
# Block syntax.
tokens.AdvanceOver(_Token.CLOSE_MUSTACHE)
section = self._ParseSection(tokens)
else_node_class = next_token.ElseNodeClass() # may not have one
else_section = None
if (else_node_class is not None and
tokens.next_token is _Token.OPEN_ELSE):
self._OpenElse(tokens, id_)
else_section = self._ParseSection(tokens)
self._CloseSection(tokens, id_)
nodes = []
if section is not None:
node = next_token.clazz(bind_to, id_, section)
if partial_args:
node.SetArguments(partial_args)
nodes.append(node)
if else_section is not None:
nodes.append(else_node_class(bind_to, id_, else_section))
return nodes
elif next_token is _Token.OPEN_COMMENT:
# Comments.
start_line = tokens.next_line
self._AdvanceOverComment(tokens)
return [_CommentNode(start_line, tokens.next_line)]
def _AdvanceOverComment(self, tokens):
tokens.AdvanceOver(_Token.OPEN_COMMENT)
depth = 1
while tokens.HasNext() and depth > 0:
if tokens.next_token is _Token.OPEN_COMMENT:
depth += 1
elif tokens.next_token is _Token.CLOSE_COMMENT:
depth -= 1
tokens.Advance()
def _CloseSection(self, tokens, id_):
tokens.AdvanceOver(_Token.OPEN_END_SECTION,
description='to match %s' % id_.GetDescription())
next_string = tokens.AdvanceOverNextString()
if next_string != '' and next_string != id_.name:
raise ParseException(
'Start section %s doesn\'t match end %s' % (id_, next_string))
tokens.AdvanceOver(_Token.CLOSE_MUSTACHE)
def _OpenElse(self, tokens, id_):
tokens.AdvanceOver(_Token.OPEN_ELSE)
next_string = tokens.AdvanceOverNextString()
if next_string != '' and next_string != id_.name:
raise ParseException(
'Start section %s doesn\'t match else %s' % (id_, next_string))
tokens.AdvanceOver(_Token.CLOSE_MUSTACHE)
def _ParsePartialNodeArgs(self, tokens):
args = {}
tokens.SkipWhitespace()
while (tokens.next_token is _Token.CHARACTER and
tokens.NextCharacter() != ')'):
key = tokens.AdvanceOverNextString(excluded=':')
tokens.AdvanceOverSeparator(':')
if tokens.NextCharacter() == '(':
tokens.AdvanceOverSeparator('(')
inner_id = self._NextIdentifier(tokens)
inner_args = self._ParsePartialNodeArgs(tokens)
tokens.AdvanceOverSeparator(')')
args[key] = {inner_id: inner_args}
else:
args[key] = self._NextIdentifier(tokens)
return args or None
def _NextIdentifier(self, tokens):
tokens.SkipWhitespace()
column_start = tokens.next_column + 1
id_ = _Identifier(tokens.AdvanceOverNextString(excluded=' \n\r\t:()'),
tokens.next_line,
column_start)
tokens.SkipWhitespace()
return id_
def Render(self, *user_contexts):
'''Renders this template given a variable number of contexts to read out
values from (such as those appearing in {{foo}}).
'''
internal_context = _InternalContext()
contexts = list(user_contexts)
contexts.append({
'_': internal_context,
'false': False,
'true': True,
})
render_state = _RenderState(self._name or '<root>', _Contexts(contexts))
internal_context.SetRenderState(render_state)
self._top_node.Render(render_state)
return render_state.GetResult()
def render(self, *contexts):
return self.Render(*contexts)
def __eq__(self, other):
return self.source == other.source and self._name == other._name
def __ne__(self, other):
return not (self == other)
def __repr__(self):
return str('%s(%s)' % (type(self).__name__, self._top_node))
def __str__(self):
return repr(self)
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