+(* goaljobs
+ * Copyright (C) 2013 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *)
+
+(* For general information about camlp4, see:
+ * http://brion.inria.fr/gallium/index.php/Camlp4
+ *
+ * For information about quotations, see:
+ * http://brion.inria.fr/gallium/index.php/Quotation
+ *)
+
+open Printf
+
+open Camlp4.PreCast
+open Syntax
+open Ast
+
+let locfail _loc msg = Loc.raise _loc (Failure msg)
+
+(* 'expr' is a function expression (RHS of a binding). It has the
+ * form 'fun a -> fun b -> ...'. Return the parameters and the body of
+ * the function.
+ *)
+let rec function_parameters = function
+ (* fun patt -> expr *)
+ | ExFun (_loc, McArr (_ploc, param, ExNil _, expr)) ->
+ let params, body = function_parameters expr in
+ ((_ploc, param) :: params), body
+ (* patt when expr -> expr *)
+ | ExFun (_loc, McArr (_, _, _, expr)) ->
+ locfail _loc "not supported: goal function uses when-clause"
+ | body -> [], body
+
+(* Define one or more 'let [rec] goal ... [and ...]' expressions.
+ *
+ * 'r' is Some _ if the rec keyword was defined. 'lets' is the list
+ * of let statements.
+ *)
+let generate_let_goal _loc (r : rec_flag) (lets : binding) =
+ (* lets might be a single binding, or multiple bindings using BiAnd
+ * ('let .. and'). Rewrite each individual goal in the list.
+ *)
+ let rec rewrite = function
+ | BiNil _loc -> BiNil _loc
+
+ (* let goal left = ... and right = ... *)
+ | BiAnd (_loc, left, right) ->
+ BiAnd (_loc, rewrite left, rewrite right)
+
+ (* let goal name = expr *)
+ | BiEq (_loc, PaId (_, (IdLid (_, name))), expr) ->
+ (* Rename the function to goal_<name>. *)
+ let gname = "goal_" ^ name in
+
+ (* Split the function into parameters and body. *)
+ let params, body = function_parameters expr in
+
+ if params = [] then
+ locfail _loc "goal must have some parameters; you probably want to put '()' here";
+
+ (* Put a try-clause around the body. *)
+ let body = <:expr< try $body$ with Goal_result Goal_OK -> () >> in
+
+ (* Recreate the function with parameters. *)
+ let expr =
+ List.fold_right (
+ fun (_ploc, param) rest ->
+ ExFun (_loc, McArr (_ploc, param, ExNil _ploc, rest))
+ ) params body in
+
+ <:binding< $lid:gname$ = $expr$ >>
+ | _ ->
+ locfail _loc "cannot parse 'let goal' expression"
+ in
+ let lets = rewrite lets in
+
+ (* let [rec] ... and ... in () *)
+ Ast.StVal (_loc, r, lets)
+
+(* Rewrite 'require (name args...)' as 'require (goal_name args)'.
+ * 'expr' is a function call.
+ *)
+let generate_require _loc expr =
+ (* Note that 'f a b c' is parsed as '((f a) b) c' so the actually
+ * function name is buried deeply in the tree. Rewrite the name.
+ *)
+ let rec rewrite = function
+ | ExApp (_loc, ExId (_loc1, IdLid (_loc2, name)), right) ->
+ let gname = "goal_" ^ name in
+ ExApp (_loc, ExId (_loc1, IdLid (_loc2, gname)), right)
+ | ExApp (_loc, (ExApp _ as expr), right) ->
+ ExApp (_loc, rewrite expr, right)
+ | _ ->
+ locfail _loc "require (...) expression must contain a call to a goal"
+ in
+ let expr = rewrite expr in
+ <:expr< Goaljobs.require ($expr$) >>
+
+;;
+
+EXTEND Gram
+ GLOBAL: expr str_item;
+
+ (* Rewrite 'require (name args...)'. *)
+ expr: LEVEL "apply" [
+ [ "require"; e = expr ->
+ generate_require _loc e ]
+ ];
+
+ (* "str_item" is a top level statement in an OCaml program. *)
+ str_item: LEVEL "top" [
+ [ "let"; r = opt_rec; "goal"; ls = binding ->
+ generate_let_goal _loc r ls ]
+ ];
+
+END
git.annexia.org / goaljobs.git / commitdiff