1 files changed, 72 insertions, 0 deletions
diff --git a/docs/examples/inline_gettext_extension.py b/docs/examples/inline_gettext_extension.py
new file mode 100644
index 00000000..d75119cf
--- /dev/null
+++ b/docs/examples/inline_gettext_extension.py
@@ -0,0 +1,72 @@
+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 1:
+                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,
+            )