doc_type :: Type -> Doc
doc_type TVoid         = text "void"
doc_type TInt          = text "int"
doc_type TFloat        = text "float"
doc_type TChar         = text "char"
doc_type (TPtr tp)     = (doc_type tp) <> text "*"
doc_type (TStruct str) = text "struct" <+> text str

exp_doc :: Exp -> Doc
exp_doc (EIdent str)                = text str
exp_doc (ELit either)               = if isLeft either
                                                then text (show (head (lefts [either])))
                                                else text (rights [either])
exp_doc (EBinOp str exp1 exp2)      = exp_doc exp1 <+> text str <+> exp_doc exp2
exp_doc (EUnOpPre str exp)          = text str <> exp_doc exp
exp_doc (EUnOpPost str exp)         = exp_doc exp <> text str
exp_doc (EFunCall exp exps)        = exp_doc exp <> text "("
                                                  <> exp_list_concat_doc exps
                                                  <> text ")"

case_doc :: Case -> Doc
case_doc CDefault   = text "default:""
case_doc (CInt int) = text "case" <+> text (show int) <> text ":"
case_doc (CChar c)  = text "case" <+> text c <> text ":"

stmt_doc :: Stmt -> Doc
stmt_doc SBreak                           = text "break;"
stmt_doc SContinue                        = text "continue;"
stmt_doc (SLoc tp str maybe_exp)          = doc_type tp <+> text str <+> doc
                                                                    where doc = if isNothing maybe_exp
                                                                                            then text ";"
                                                                                            else text " = "
                                                                   <> exp_doc (fromJust maybe_exp)
                                                                  <> text ";"
stmt_doc (SExp exp)                       = exp_doc exp <> text ";"
stmt_doc (SReturn exp)                    = text "return" <+> exp_doc exp <> text ";"
stmt_doc (SBlock stmts)                   = text "{" <> nest 2 (statements stmts) <!> text "}"
stmt_doc (SIf exp stmt m_stmt)              = text "if (" <> exp_doc exp <> text ")"
                                                                <+> stmt_doc stmt <> text "" <> doc
                                                                      where doc = if isNothing m_stmt
                                                                                              then text ""
                                                                                              else line
                                                                     <> text "else "
                                                                     <> stmt_doc(fromJust m_stmt)
stmt_doc (SSwitch Exp [Either Case Stmt]) =