refactoring
cache the module function info, coz the depth info returned by int
module isn't telling the truth when the function call is the last expression
fix the problem where if function call is in the last expression of a
function, it is not displayed
fix the clause display bug
fix the problem where if there is only one expression in the function
definition, its variables will not be replaced
Merge pull request #33 from liuhongchao/fix-clause-bug

Fix clause bug