class Parser(object):
def __init__(self, fail_gracefully=True):
self.fail_gracefully = fail_gracefully
def parse(self, template_name, templates):
"""
Creates an AST for the given template. Returns a Template object.
"""
self.templates = templates # Maps template names to template sources.
self.root = Template(template_name)
self.stack = [self.root]
self.current = self.root
self.tokens = Lexer(self.templates[template_name], 'django-pancake').tokenize()
_TOKEN_TEXT, _TOKEN_VAR, _TOKEN_BLOCK = TOKEN_TEXT, TOKEN_VAR, TOKEN_BLOCK
while self.tokens:
token = self.next_token()
if token.token_type == _TOKEN_TEXT:
self.current.leaves.append(token.contents)
elif token.token_type == _TOKEN_VAR:
if token.contents == 'block.super':
if self.root.parent is None:
raise PancakeFail('Got {{ block.super }} in a template that has no parent')
super_block_name = self.stack[-1].name
current_par = self.root.parent
while current_par is not None:
if super_block_name in current_par.blocks:
self.current.leaves.extend(current_par.blocks[super_block_name].leaves)
break
current_par = current_par.parent
else:
self.current.leaves.append('{{ %s }}' % token.contents)
elif token.token_type == _TOKEN_BLOCK:
try:
tag_name, arg = token.contents.split(None, 1)
except ValueError:
tag_name, arg = token.contents.strip(), None
method_name = 'do_%s' % tag_name
if hasattr(self, method_name):
getattr(self, method_name)(arg)
else:
self.current.leaves.append('{%% %s %%}' % token.contents)
return self.root
def next_token(self):
return self.tokens.pop(0)
def do_block(self, text):
if not text:
raise PancakeFail('{% block %} without a name')
self.current.leaves.append(Block(text))
self.root.blocks[text] = self.current = self.current.leaves[-1]
self.stack.append(self.current)
def do_endblock(self, text):
self.stack.pop()
self.current = self.stack[-1]
def do_extends(self, text):
if not text:
raise PancakeFail('{%% extends %%} without an argument (file: %r)' % self.root.name)
if text[0] in ('"', "'"):
parent_name = text[1:-1]
self.root.parent = Parser().parse(parent_name, self.templates)
else:
raise PancakeFail('Variable {%% extends %%} tags are not supported (file: %r)' % self.root.name)
def do_comment(self, text):
# Consume all tokens until 'endcomment'
while self.tokens:
token = self.next_token()
if token.token_type == TOKEN_BLOCK:
try:
tag_name, arg = token.contents.split(None, 1)
except ValueError:
tag_name, arg = token.contents.strip(), None
if tag_name == 'endcomment':
break
def do_load(self, text):
# Keep track of which template libraries have been loaded,
# so that we can pass them up to the root.
self.root.loads.update(text.split())
def do_include(self, text):
if ' only' in text:
if self.fail_gracefully:
self.current.leaves.append('{%% include %s %%}' % text)
return
else:
raise PancakeFail('{%% include %%} tags containing "only" are not supported (file: %r)' % self.root.name)
try:
template_name, rest = text.split(None, 1)
except ValueError:
template_name, rest = text, ''
if not template_name[0] in ('"', "'"):
if self.fail_gracefully:
self.current.leaves.append('{%% include %s %%}' % text)
return
else:
raise PancakeFail('Variable {%% include %%} tags are not supported (file: %r)' % self.root.name)
template_name = template_name[1:-1]
if rest.startswith('with '):
rest = rest[5:]
include_node = Parser().parse(template_name, self.templates)
# Add {% load %} tags from the included template.
self.root.loads.update(include_node.loads)
if rest:
self.current.leaves.append('{%% with %s %%}' % rest)
self.current.leaves.extend(include_node.leaves)
if rest:
self.current.leaves.append('{% endwith %}')
class Parser(object):
def __init__(self, fail_gracefully=True):
self.fail_gracefully = fail_gracefully
def parse(self, template_name, templates):
"""
Creates an AST for the given template. Returns a Template object.
"""
self.templates = templates # Maps template names to template sources.
self.root = Template(template_name)
self.stack = [self.root]
self.current = self.root
self.tokens = Lexer(self.templates[template_name]).tokenize()
_TOKEN_TEXT, _TOKEN_VAR, _TOKEN_BLOCK = TokenType.TEXT, TokenType.VAR, TokenType.BLOCK
while self.tokens:
token = self.next_token()
if token.token_type == _TOKEN_TEXT:
self.current.leaves.append(token.contents)
elif token.token_type == _TOKEN_VAR:
if token.contents == 'block.super':
if self.root.parent is None:
raise PancakeFail(
'Got {{ block.super }} in a template that has no parent'
)
super_block_name = self.stack[-1].name
current_par = self.root.parent
while current_par is not None:
if super_block_name in current_par.blocks:
self.current.leaves.extend(
current_par.blocks[super_block_name].leaves)
break
current_par = current_par.parent
else:
self.current.leaves.append('{{ %s }}' % token.contents)
elif token.token_type == _TOKEN_BLOCK:
try:
tag_name, arg = token.contents.split(None, 1)
except ValueError:
tag_name, arg = token.contents.strip(), None
method_name = 'do_%s' % tag_name
if hasattr(self, method_name):
getattr(self, method_name)(arg)
else:
self.current.leaves.append('{%% %s %%}' % token.contents)
return self.root
def next_token(self):
return self.tokens.pop(0)
def do_block(self, text):
if not text:
raise PancakeFail('{% block %} without a name')
self.current.leaves.append(Block(text))
self.root.blocks[text] = self.current = self.current.leaves[-1]
self.stack.append(self.current)
def do_endblock(self, text):
self.stack.pop()
self.current = self.stack[-1]
def do_extends(self, text):
if not text:
raise PancakeFail(
'{%% extends %%} without an argument (file: %r)' %
self.root.name)
if text[0] in ('"', "'"):
parent_name = text[1:-1]
self.root.parent = Parser().parse(parent_name, self.templates)
else:
raise PancakeFail(
'Variable {%% extends %%} tags are not supported (file: %r)' %
self.root.name)
def do_comment(self, text):
# Consume all tokens until 'endcomment'
while self.tokens:
token = self.next_token()
if token.token_type == TokenType.BLOCK:
try:
tag_name, arg = token.contents.split(None, 1)
except ValueError:
tag_name, arg = token.contents.strip(), None
if tag_name == 'endcomment':
break
def do_load(self, text):
# Keep track of which template libraries have been loaded,
# so that we can pass them up to the root.
self.root.loads.update(text.split())
def do_include(self, text):
if ' only' in text:
if self.fail_gracefully:
self.current.leaves.append('{%% include %s %%}' % text)
return
else:
raise PancakeFail(
'{%% include %%} tags containing "only" are not supported (file: %r)'
% self.root.name)
try:
template_name, rest = text.split(None, 1)
except ValueError:
template_name, rest = text, ''
if not template_name[0] in ('"', "'"):
if self.fail_gracefully:
self.current.leaves.append('{%% include %s %%}' % text)
return
else:
raise PancakeFail(
'Variable {%% include %%} tags are not supported (file: %r)'
% self.root.name)
template_name = template_name[1:-1]
if rest.startswith('with '):
rest = rest[5:]
include_node = Parser().parse(template_name, self.templates)
# Add {% load %} tags from the included template.
self.root.loads.update(include_node.loads)
if rest:
self.current.leaves.append('{%% with %s %%}' % rest)
self.current.leaves.extend(include_node.leaves)
if rest:
self.current.leaves.append('{% endwith %}')
