annotate src/mono_reduce.sml @ 167:2be573fec9a6

Unurlifying a datatype; longjmp-based error signaling mechanism
author Adam Chlipala <adamc@hcoop.net>
date Tue, 29 Jul 2008 15:25:42 -0400
parents 55d8cfa4d024
children 25b169416ea8
rev   line source
adamc@133 1 (* Copyright (c) 2008, Adam Chlipala
adamc@133 2 * All rights reserved.
adamc@133 3 *
adamc@133 4 * Redistribution and use in source and binary forms, with or without
adamc@133 5 * modification, are permitted provided that the following conditions are met:
adamc@133 6 *
adamc@133 7 * - Redistributions of source code must retain the above copyright notice,
adamc@133 8 * this list of conditions and the following disclaimer.
adamc@133 9 * - Redistributions in binary form must reproduce the above copyright notice,
adamc@133 10 * this list of conditions and the following disclaimer in the documentation
adamc@133 11 * and/or other materials provided with the distribution.
adamc@133 12 * - The names of contributors may not be used to endorse or promote products
adamc@133 13 * derived from this software without specific prior written permission.
adamc@133 14 *
adamc@133 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
adamc@133 16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
adamc@133 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
adamc@133 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
adamc@133 19 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
adamc@133 20 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
adamc@133 21 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
adamc@133 22 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
adamc@133 23 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
adamc@133 24 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
adamc@133 25 * POSSIBILITY OF SUCH DAMAGE.
adamc@133 26 *)
adamc@133 27
adamc@133 28 (* Simplify a Mono program algebraically *)
adamc@133 29
adamc@133 30 structure MonoReduce :> MONO_REDUCE = struct
adamc@133 31
adamc@133 32 open Mono
adamc@133 33
adamc@133 34 structure E = MonoEnv
adamc@133 35 structure U = MonoUtil
adamc@133 36
adamc@133 37 val liftExpInExp =
adamc@133 38 U.Exp.mapB {typ = fn t => t,
adamc@133 39 exp = fn bound => fn e =>
adamc@133 40 case e of
adamc@133 41 ERel xn =>
adamc@133 42 if xn < bound then
adamc@133 43 e
adamc@133 44 else
adamc@133 45 ERel (xn + 1)
adamc@133 46 | _ => e,
adamc@133 47 bind = fn (bound, U.Exp.RelE _) => bound + 1
adamc@133 48 | (bound, _) => bound}
adamc@133 49
adamc@133 50 val subExpInExp =
adamc@133 51 U.Exp.mapB {typ = fn t => t,
adamc@133 52 exp = fn (xn, rep) => fn e =>
adamc@133 53 case e of
adamc@133 54 ERel xn' =>
adamc@133 55 (case Int.compare (xn', xn) of
adamc@133 56 EQUAL => #1 rep
adamc@133 57 | GREATER=> ERel (xn' - 1)
adamc@133 58 | LESS => e)
adamc@133 59 | _ => e,
adamc@133 60 bind = fn ((xn, rep), U.Exp.RelE _) => (xn+1, liftExpInExp 0 rep)
adamc@133 61 | (ctx, _) => ctx}
adamc@133 62
adamc@133 63 fun bind (env, b) =
adamc@133 64 case b of
adamc@133 65 U.Decl.NamedT (x, n, co) => E.pushTNamed env x n co
adamc@133 66 | U.Decl.RelE (x, t) => E.pushERel env x t
adamc@133 67 | U.Decl.NamedE (x, n, t, eo, s) => E.pushENamed env x n t eo s
adamc@133 68
adamc@133 69 fun typ c = c
adamc@133 70
adamc@133 71 fun exp env e =
adamc@133 72 case e of
adamc@133 73 ENamed n =>
adamc@133 74 (case E.lookupENamed env n of
adamc@133 75 (_, _, SOME e', _) => #1 e'
adamc@133 76 | _ => e)
adamc@133 77
adamc@133 78 | EApp ((EAbs (_, _, _, e1), loc), e2) =>
adamc@133 79 #1 (reduceExp env (subExpInExp (0, e2) e1))
adamc@133 80
adamc@133 81 | _ => e
adamc@133 82
adamc@133 83 and reduceExp env = U.Exp.mapB {typ = typ, exp = exp, bind = bind} env
adamc@133 84
adamc@133 85 fun decl env d = d
adamc@133 86
adamc@133 87 val reduce = U.File.mapB {typ = typ, exp = exp, decl = decl, bind = bind} E.empty
adamc@133 88
adamc@133 89 end