jinja2/docs/examples/inline_gettext_extension.py

73 lines
2.3 KiB
Python

import re
from jinja2.exceptions import TemplateSyntaxError
from jinja2.ext import Extension
from jinja2.lexer import count_newlines
from jinja2.lexer import Token
_outside_re = re.compile(r"\\?(gettext|_)\(")
_inside_re = re.compile(r"\\?[()]")
class InlineGettext(Extension):
"""This extension implements support for inline gettext blocks::
<h1>_(Welcome)</h1>
<p>_(This is a paragraph)</p>
Requires the i18n extension to be loaded and configured.
"""
def filter_stream(self, stream):
paren_stack = 0
for token in stream:
if token.type != "data":
yield token
continue
pos = 0
lineno = token.lineno
while True:
if not paren_stack:
match = _outside_re.search(token.value, pos)
else:
match = _inside_re.search(token.value, pos)
if match is None:
break
new_pos = match.start()
if new_pos > pos:
preval = token.value[pos:new_pos]
yield Token(lineno, "data", preval)
lineno += count_newlines(preval)
gtok = match.group()
if gtok[0] == "\\":
yield Token(lineno, "data", gtok[1:])
elif not paren_stack:
yield Token(lineno, "block_begin", None)
yield Token(lineno, "name", "trans")
yield Token(lineno, "block_end", None)
paren_stack = 1
else:
if gtok == "(" or paren_stack > 1:
yield Token(lineno, "data", gtok)
paren_stack += -1 if gtok == ")" else 1
if not paren_stack:
yield Token(lineno, "block_begin", None)
yield Token(lineno, "name", "endtrans")
yield Token(lineno, "block_end", None)
pos = match.end()
if pos < len(token.value):
yield Token(lineno, "data", token.value[pos:])
if paren_stack:
raise TemplateSyntaxError(
"unclosed gettext expression",
token.lineno,
stream.name,
stream.filename,
)