src/tree.sml

   1 (*
   2  * Dynamic web page generation with Standard ML
   3  * Copyright (C) 2003  Adam Chlipala
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2.1 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  *)
  19
  20 (* Template language abstract syntax trees *)
  21
  22 structure Tree =
  23 struct
  24     open Common
  25
  26     type ident = string
  27     type path = ident list
  28
  29     type 'a withext = 'a * (int * int)
  30
  31     (* Pattern *)
  32     datatype pat' =
  33         Wild_p | Int_p of int | String_p of string
  34       | Ident_p of path
  35       | Record_p of bool * (ident * pat) list
  36       | FlexRecord_p of (ident * pat) list
  37       | App_p of path * pat | Cons_p of pat * pat
  38       | As_p of ident * pat
  39     and pat = PAT of pat' withext
  40
  41     (* Expression *)
  42     and exp' =
  43         Int_e of int | String_e of string | Char_e of string | Ident_e of path
  44       | Plus_e of exp * exp | Minus_e of exp * exp | Times_e of exp * exp
  45       | Divide_e of exp * exp | Mod_e of exp * exp | Neg_e | Param_e
  46       | Template_e of ident
  47       | Orelse_e of exp * exp | Andalso_e of exp * exp
  48       | StrCat_e of exp * exp
  49       | Eq_e of exp * exp | Neq_e of exp * exp
  50       | Gt_e of exp * exp | Gte_e of exp * exp
  51       | Lt_e of exp * exp | Lte_e of exp * exp
  52       | Cons_e of exp * exp
  53       | Record_e of bool * (ident * exp) list
  54       | RecordUpd_e of exp * (ident * exp) list
  55       | Proj_e of ident | App_e of exp * exp
  56     and exp = EXP of exp' withext
  57
  58     and blockItem' =
  59         Html_i of string                                    (* literal HTML code to be sent *)
  60       | Ref_i of (ident * exp) list                         (* define some new refs *)
  61       | Val_i of pat * exp                                  (* val binding *)
  62       | Assn_i of ident * exp                               (* assignment to ref *)
  63       | Exp_i of exp                                        (* expression to be evaluated *)
  64       | Open_i of path list                                 (* imports to top level *)
  65       | Ifthenelse_i of (exp * block) list * block option   (* if statement *)
  66       | Case_i of exp * (pat * block) list                  (* case statement *)
  67       | Foreach_i of ident * exp * block                    (* foreach statement with list *)
  68       | For_i of ident * exp * exp * block                  (* foreach statement with integer range *)
  69       | TryCatch_i of block * (pat * block) list            (* try...catch exception handlers w/ pattern matching *)
  70     and blockItem = BITEM of blockItem' withext
  71     (* Block of thingers to twiddle *)
  72     and block = BLOCK of block' withext
  73     withtype block' = blockItem list
  74     and path = ident list
  75
  76     fun unblock (BLOCK (x, _)) = x
  77     fun unpat (PAT (x, _)) = x
  78     fun unexp (EXP (x, _)) = x
  79
  80
  81     fun expString (EXP (e, _)) =
  82         (case e of
  83              Int_e n => Int.toString n
  84            | String_e s => "\"" ^ s ^ "\""
  85            | Ident_e [id] => id
  86            | Ident_e [sn, id] => sn ^ "." ^ id
  87            | Plus_e (e1, e2) => expString e1 ^ " + " ^ expString e2
  88            | Minus_e (e1, e2) => expString e1 ^ " - " ^ expString e2
  89            | Orelse_e (e1, e2) => expString e1 ^ " || " ^ expString e2
  90            | Andalso_e (e1, e2) => expString e1 ^ " && " ^ expString e2
  91            | Times_e (e1, e2) => expString e1 ^ " * " ^ expString e2
  92            | Divide_e (e1, e2) => expString e1 ^ " / " ^ expString e2
  93            | Mod_e (e1, e2) => expString e1 ^ " % " ^ expString e2
  94            | Eq_e (e1, e2) => expString e1 ^ " = " ^ expString e2
  95            | Neq_e (e1, e2) => expString e1 ^ " <> " ^ expString e2
  96            | Gt_e (e1, e2) => expString e1 ^ " > " ^ expString e2
  97            | Gte_e (e1, e2) => expString e1 ^ " >= " ^ expString e2
  98            | Lt_e (e1, e2) => expString e1 ^ " < " ^ expString e2
  99            | Lte_e (e1, e2) => expString e1 ^ " <= " ^ expString e2
 100            | Neg_e => "-"
 101            | Param_e => "$"
 102            | Template_e id => "@" ^ id
 103            | Cons_e (e1, e2) => expString e1 ^ " :: " ^ expString e2
 104            | Record_e (true, elms) => foldl (fn ((_, e), s) => s ^ ", " ^ expString e) "(" elms ^ ")"
 105            | Record_e (false, elms) => foldl (fn ((lab, e), s) => s ^ ", " ^ lab ^ " = " ^ expString e) "(" elms ^ ")"
 106            | RecordUpd_e _ => "<RECORDUPDATE>"
 107            | Proj_e id => "#" ^ id
 108            | App_e (e1, e2) => expString e1 ^ "(" ^ expString e2 ^ ")"
 109            | _ => "<NUTTY>")
 110
 111     fun pathString [] = "<ERROR>"
 112       | pathString [id] = id
 113       | pathString (h::t) = h ^ "." ^ pathString t
 114 end