Dangling Else Ambiguity

Halp /prog/, I want to solve the Dangling Else Ambiguity here but I keep screwing it up.

void IfStmt() : {}
{
        <IF> Expr() <THEN> Stmt()
    |    <IF> Expr() <THEN> Stmt() <ELSE> Stmt()
}

void Stmt() : {}
{
        Assignment()
    |    IfStmt()
    |    WhileStmt()
    |    CaseStmt()
    |    Function()
    |    IOStmt()
    |    Block()
    |    Return()
}

>>14
Is that some kind of haskellFag concentration camp?