Parse the language of a PostgreSQL function also when prefix

This is the way pg_dump saves it.

2 files changed, 16 insertions, 2 deletions

diff --git a/pygments/lexers/postgres.py b/pygments/lexers/postgres.py
index fe9a8a22..36717d4f 100644
--- a/pygments/lexers/postgres.py
+++ b/pygments/lexers/postgres.py
@@ -67,10 +67,14 @@ def language_callback(lexer, match):
     rules deepcopy fails in this case.
     """
     l = None
-    # TODO: the language can also be before the string
-    m = language_re.match(lexer.text[match.end():])
+    m = language_re.match(lexer.text[match.end():match.end()+100])
     if m is not None:
         l = lexer._get_lexer(m.group(1))
+    else:
+        m = list(language_re.finditer(
+            lexer.text[max(0, match.start()-100):match.start()]))
+        if m:
+            l = lexer._get_lexer(m[-1].group(1))
 
     if l:
         yield (match.start(1), String, match.group(1))
diff --git a/tests/examplefiles/postgresql_test.txt b/tests/examplefiles/postgresql_test.txt
index 23bb6d03..fa0914e3 100644
--- a/tests/examplefiles/postgresql_test.txt
+++ b/tests/examplefiles/postgresql_test.txt
@@ -32,3 +32,13 @@ END;
 $$
 LANGUAGE plpgsql;
 
+-- As returned by pg_dump
+CREATE FUNCTION test_function() RETURNS integer
+    LANGUAGE plpgsql STABLE STRICT
+    AS $$
+begin
+    return 42;
+end
+$$;
+
+