Pythonならこんなモノがある。

Python Omni Completion
http://www.vim.org/scripts/script.php?script_id=1542

Features:
Dynamic type deduction (without actually evaluating statements) #動的に型を特定
Local visibility handling (will complete from all parent scopes). #親の可視範囲から型を特定
completeopt=preview support, displaying python docstrings # 略
Function argument completion (whenever possible) # 引数補完