diff -r 0bcc13460dae -r 65efd0c6919f pgtoolkit/pgbrowser.py
--- a/pgtoolkit/pgbrowser.py	Thu Jan 24 17:11:17 2013 +0100
+++ b/pgtoolkit/pgbrowser.py	Fri Jan 25 17:06:54 2013 +0100
@@ -113,17 +113,45 @@
     indexes = property(getindexes)
 
 
-class Function:
-    def __init__(self, browser, schema, oid, name, type, arguments, result, source):
+class Argument:
+    def __init__(self, browser, function, name, type, mode, default):
+        # PgBrowser instance
         self.browser = browser
-        self.oid = oid
+        # Function instance
+        self.function = function
         self.name = name
         self.type = type
-        self.arguments = arguments
+        self.mode = mode
+        self.default = default
+
+class Function:
+    def __init__(self, browser, schema, oid, name, function_name, type, result, source):
+        self.browser = browser
+        self.schema = schema
+        self.oid = oid
+        #: unique name - function name + arg types
+        self.name = name
+        #: pure function name without args
+        self.function_name = function_name
+        self.type = type
         self.result = result
         self.source = source
+        self._arguments = None
         self._definition = None
 
+    def refresh(self):
+        self.refresh_args()
+
+    def refresh_args(self):
+        rows = self.browser.list_function_args(self.oid)
+        self._arguments = OrderedDict([(x['name'], Argument(self.browser, self, **x)) for x in rows])
+
+    @property
+    def arguments(self):
+        if self._arguments is None:
+            self.refresh_args()
+        return self._arguments
+
     @property
     def definition(self):
         """Get full function definition including CREATE command."""
@@ -306,9 +334,12 @@
         return self._query('''
             SELECT
                 p.oid as "oid",
-                p.proname as "name",
+                p.proname || '(' || array_to_string(
+                    array(SELECT pg_catalog.format_type(unnest(p.proargtypes), NULL)),
+                      ', '
+                ) || ')' as "name",
+                p.proname as "function_name",
                 pg_catalog.pg_get_function_result(p.oid) as "result",
-                pg_catalog.pg_get_function_arguments(p.oid) as "arguments",
                 p.prosrc as "source",
                 CASE
                     WHEN p.proisagg THEN 'agg'
@@ -318,11 +349,41 @@
                 END as "type"
             FROM pg_catalog.pg_proc p
             LEFT JOIN pg_catalog.pg_namespace n ON n.oid = p.pronamespace
-            WHERE pg_catalog.pg_function_is_visible(p.oid)
-                AND n.nspname = %s
+            WHERE n.nspname = %s
             ORDER BY 1, 2, 4;
             ''', [schema])
 
+    def list_function_args(self, oid):
+        """List function arguments.
+
+        Notes about query:
+            type: Use allargtypes if present, argtypes otherwise.
+                The trick with [0:999] moves lower bound from 0 to default 1
+                by slicing all elements (slices has always lower bound 1).
+            mode: This trick makes array of NULLs of same length as argnames,
+                in case argmodes is NULL.
+            default: Use pg_get_expr, split output by ', '
+                FIXME: will fail if ', ' is present in default value string.
+        """
+        return self._query('''
+            SELECT
+              unnest(p.proargnames) AS "name",
+              pg_catalog.format_type(unnest(
+                COALESCE(p.proallargtypes, (p.proargtypes::oid[])[0:999])
+              ), NULL) AS "type",
+              unnest(
+                COALESCE(
+                  p.proargmodes::text[],
+                  array(SELECT NULL::text FROM generate_series(1, array_upper(p.proargnames, 1)))
+                )
+              ) AS "mode",
+              unnest(array_cat(
+                array_fill(NULL::text, array[COALESCE(array_upper(p.proargnames,1),0) - p.pronargdefaults]),
+                string_to_array(pg_get_expr(p.proargdefaults, 'pg_proc'::regclass, true), ', ')
+              )) AS "default"
+            FROM pg_proc p
+            WHERE p.oid = %s''', [oid])
+
     def get_function_definition(self, oid):
         """Get full function definition, including CREATE command etc.