| 1 | (* HCoop Domtool (http://hcoop.sourceforge.net/) |
| 2 | * Copyright (c) 2006-2007, Adam Chlipala |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or |
| 5 | * modify it under the terms of the GNU General Public License |
| 6 | * as published by the Free Software Foundation; either version 2 |
| 7 | * of the License, or (at your option) any later version. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License |
| 15 | * along with this program; if not, write to the Free Software |
| 16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. |
| 17 | *) |
| 18 | |
| 19 | (* Configuration language abstract syntax *) |
| 20 | |
| 21 | structure Ast = struct |
| 22 | |
| 23 | open DataStructures |
| 24 | |
| 25 | (* A description of a predicate on configuration block stacks *) |
| 26 | datatype pred' = |
| 27 | CRoot |
| 28 | (* The stack is empty. *) |
| 29 | | CConst of string |
| 30 | (* The given pred name is on top of the stack. *) |
| 31 | | CPrefix of pred |
| 32 | (* Some prefix of the stack matches the pred. *) |
| 33 | | CNot of pred |
| 34 | (* The pred does not match. *) |
| 35 | | CAnd of pred * pred |
| 36 | (* Both preds match. *) |
| 37 | withtype pred = pred' * position |
| 38 | |
| 39 | datatype typ' = |
| 40 | TBase of string |
| 41 | (* Base type *) |
| 42 | | TList of typ |
| 43 | (* SML 'a list *) |
| 44 | | TArrow of typ * typ |
| 45 | (* SML -> *) |
| 46 | | TAction of pred * record * record |
| 47 | (* An action that: |
| 48 | * - Is valid in the given pred |
| 49 | * - Expects an environment compatible with the first record |
| 50 | * - Modifies it according to the second record *) |
| 51 | | TNested of pred * typ |
| 52 | (* Allow nested configuration, in the form of a function from an action |
| 53 | * satisfying the first predicate to an action satisfying the second and |
| 54 | * with the same environment variable IO behavior. *) |
| 55 | |
| 56 | | TError |
| 57 | (* Marker that something already went wrong, so don't generate further |
| 58 | * error messages. *) |
| 59 | | TUnif of string * typ option ref |
| 60 | (* Unification variable to be determined during type-checking *) |
| 61 | withtype typ = typ' * position |
| 62 | and record = (typ' * position) StringMap.map |
| 63 | |
| 64 | datatype exp' = |
| 65 | EInt of int |
| 66 | (* Constant integer *) |
| 67 | | EString of string |
| 68 | (* Constant string *) |
| 69 | | EList of exp list |
| 70 | (* Basic list constructor *) |
| 71 | |
| 72 | | ELam of string * typ option * exp |
| 73 | (* Function abstraction *) |
| 74 | | EVar of string |
| 75 | (* Variable bound by a function *) |
| 76 | | EApp of exp * exp |
| 77 | (* Function application *) |
| 78 | |
| 79 | | ESkip |
| 80 | (* Do-nothing action *) |
| 81 | | ESet of string * exp |
| 82 | (* Set an environment variable *) |
| 83 | | EGet of string * typ option * string * exp |
| 84 | (* Get an environment variable *) |
| 85 | | ESeq of exp list |
| 86 | (* Monad sequencer; execute a number of commands in order *) |
| 87 | | ELocal of exp * exp |
| 88 | (* Local execution; like ESeq, but the writes of the first |
| 89 | * action are abandoned *) |
| 90 | | EWith of exp * exp |
| 91 | (* Apply a TNested to an action *) |
| 92 | | EALam of string * pred * exp |
| 93 | (* Abstraction for building TNested values *) |
| 94 | | EIf of exp * exp * exp |
| 95 | (* If..then..else *) |
| 96 | withtype exp = exp' * position |
| 97 | |
| 98 | datatype decl' = |
| 99 | DExternType of string |
| 100 | | DExternVal of string * typ |
| 101 | | DVal of string * typ option * exp |
| 102 | | DContext of string |
| 103 | type decl = decl' * string option * position |
| 104 | |
| 105 | type file = string option * decl list * exp option |
| 106 | |
| 107 | fun multiApp (f, loc, args) = |
| 108 | foldl (fn (arg, e) => (EApp (e, arg), loc)) f args |
| 109 | |
| 110 | datatype unification_error = |
| 111 | UnifyPred of pred * pred |
| 112 | | UnifyTyp of typ * typ |
| 113 | | UnifyOccurs of string * typ |
| 114 | |
| 115 | exception Unify of unification_error |
| 116 | |
| 117 | datatype type_error = |
| 118 | WrongType of string * exp * typ * typ * unification_error option |
| 119 | | WrongForm of string * string * exp * typ * unification_error option |
| 120 | | UnboundVariable of string |
| 121 | | WrongPred of string * pred * pred |
| 122 | |
| 123 | end |