(* Title: Tools/Compute_Oracle/am_compiler.ML
Author: Steven Obua
*)
signature COMPILING_AM =
sig
include ABSTRACT_MACHINE
val set_compiled_rewriter : (term -> term) -> unit
val list_nth : 'a list * int -> 'a
val list_map : ('a -> 'b) -> 'a list -> 'b list
end
structure AM_Compiler : COMPILING_AM = struct
val list_nth = List.nth;
val list_map = map;
open AbstractMachine;
val compiled_rewriter = ref (NONE:(term -> term)Option.option)
fun set_compiled_rewriter r = (compiled_rewriter := SOME r)
type program = (term -> term)
fun count_patternvars PVar = 1
| count_patternvars (PConst (_, ps)) =
List.foldl (fn (p, count) => (count_patternvars p)+count) 0 ps
fun print_rule (p, t) =
let
fun str x = Int.toString x
fun print_pattern n PVar = (n+1, "x"^(str n))
| print_pattern n (PConst (c, [])) = (n, "c"^(str c))
| print_pattern n (PConst (c, args)) =
let
val h = print_pattern n (PConst (c,[]))
in
print_pattern_list h args
end
and print_pattern_list r [] = r
| print_pattern_list (n, p) (t::ts) =
let
val (n, t) = print_pattern n t
in
print_pattern_list (n, "App ("^p^", "^t^")") ts
end
val (n, pattern) = print_pattern 0 p
val pattern =
if exists_string Symbol.is_ascii_blank pattern then "(" ^ pattern ^")"
else pattern
fun print_term d (Var x) = (*if x < d then "Var "^(str x) else "x"^(str (n-(x-d)-1))*)
"Var " ^ str x
| print_term d (Const c) = "c" ^ str c
| print_term d (App (a,b)) = "App (" ^ print_term d a ^ ", " ^ print_term d b ^ ")"
| print_term d (Abs c) = "Abs (" ^ print_term (d + 1) c ^ ")"
| print_term d (Computed c) = print_term d c
fun listvars n = if n = 0 then "x0" else "x"^(str n)^", "^(listvars (n-1))
val term = print_term 0 t
val term =
if n > 0 then "Closure (["^(listvars (n-1))^"], "^term^")"
else "Closure ([], "^term^")"
in
" | weak_reduce (false, stack, "^pattern^") = Continue (false, stack, "^term^")"
end
fun constants_of PVar = []
| constants_of (PConst (c, ps)) = c :: maps constants_of ps
fun constants_of_term (Var _) = []
| constants_of_term (Abs m) = constants_of_term m
| constants_of_term (App (a,b)) = (constants_of_term a)@(constants_of_term b)
| constants_of_term (Const c) = [c]
| constants_of_term (Computed c) = constants_of_term c
fun load_rules sname name prog =
let
val buffer = ref ""
fun write s = (buffer := (!buffer)^s)
fun writeln s = (write s; write "\n")
fun writelist [] = ()
| writelist (s::ss) = (writeln s; writelist ss)
fun str i = Int.toString i
val _ = writelist [
"structure "^name^" = struct",
"",
"datatype term = Dummy | App of term * term | Abs of term | Var of int | Const of int | Closure of term list * term"]
val constants = distinct (op =) (maps (fn (p, r) => ((constants_of p)@(constants_of_term r))) prog)
val _ = map (fn x => write (" | c"^(str x))) constants
val _ = writelist [
"",
"datatype stack = SEmpty | SAppL of term * stack | SAppR of term * stack | SAbs of stack",
"",
"type state = bool * stack * term",
"",
"datatype loopstate = Continue of state | Stop of stack * term",
"",
"fun proj_C (Continue s) = s",
" | proj_C _ = raise Match",
"",
"fun proj_S (Stop s) = s",
" | proj_S _ = raise Match",
"",
"fun cont (Continue _) = true",
" | cont _ = false",
"",
"fun do_reduction reduce p =",
" let",
" val s = ref (Continue p)",
" val _ = while cont (!s) do (s := reduce (proj_C (!s)))",
" in",
" proj_S (!s)",
" end",
""]
val _ = writelist [
"fun weak_reduce (false, stack, Closure (e, App (a, b))) = Continue (false, SAppL (Closure (e, b), stack), Closure (e, a))",
" | weak_reduce (false, SAppL (b, stack), Closure (e, Abs m)) = Continue (false, stack, Closure (b::e, m))",
" | weak_reduce (false, stack, c as Closure (e, Abs m)) = Continue (true, stack, c)",
" | weak_reduce (false, stack, Closure (e, Var n)) = Continue (false, stack, case "^sname^".list_nth (e, n) of Dummy => Var n | r => r)",
" | weak_reduce (false, stack, Closure (e, c)) = Continue (false, stack, c)"]
val _ = writelist (map print_rule prog)
val _ = writelist [
" | weak_reduce (false, stack, clos) = Continue (true, stack, clos)",
" | weak_reduce (true, SAppR (a, stack), b) = Continue (false, stack, App (a,b))",
" | weak_reduce (true, s as (SAppL (b, stack)), a) = Continue (false, SAppR (a, stack), b)",
" | weak_reduce (true, stack, c) = Stop (stack, c)",
"",
"fun strong_reduce (false, stack, Closure (e, Abs m)) =",
" let",
" val (stack', wnf) = do_reduction weak_reduce (false, SEmpty, Closure (Dummy::e, m))",
" in",
" case stack' of",
" SEmpty => Continue (false, SAbs stack, wnf)",
" | _ => raise ("^sname^".Run \"internal error in strong: weak failed\")",
" end",
" | strong_reduce (false, stack, clos as (App (u, v))) = Continue (false, SAppL (v, stack), u)",
" | strong_reduce (false, stack, clos) = Continue (true, stack, clos)",
" | strong_reduce (true, SAbs stack, m) = Continue (false, stack, Abs m)",
" | strong_reduce (true, SAppL (b, stack), a) = Continue (false, SAppR (a, stack), b)",
" | strong_reduce (true, SAppR (a, stack), b) = Continue (true, stack, App (a, b))",
" | strong_reduce (true, stack, clos) = Stop (stack, clos)",
""]
val ic = "(case c of "^(implode (map (fn c => (str c)^" => c"^(str c)^" | ") constants))^" _ => Const c)"
val _ = writelist [
"fun importTerm ("^sname^".Var x) = Var x",
" | importTerm ("^sname^".Const c) = "^ic,
" | importTerm ("^sname^".App (a, b)) = App (importTerm a, importTerm b)",
" | importTerm ("^sname^".Abs m) = Abs (importTerm m)",
""]
fun ec c = " | exportTerm c"^(str c)^" = "^sname^".Const "^(str c)
val _ = writelist [
"fun exportTerm (Var x) = "^sname^".Var x",
" | exportTerm (Const c) = "^sname^".Const c",
" | exportTerm (App (a,b)) = "^sname^".App (exportTerm a, exportTerm b)",
" | exportTerm (Abs m) = "^sname^".Abs (exportTerm m)",
" | exportTerm (Closure (closlist, clos)) = raise ("^sname^".Run \"internal error, cannot export Closure\")",
" | exportTerm Dummy = raise ("^sname^".Run \"internal error, cannot export Dummy\")"]
val _ = writelist (map ec constants)
val _ = writelist [
"",
"fun rewrite t = ",
" let",
" val (stack, wnf) = do_reduction weak_reduce (false, SEmpty, Closure ([], importTerm t))",
" in",
" case stack of ",
" SEmpty => (case do_reduction strong_reduce (false, SEmpty, wnf) of",
" (SEmpty, snf) => exportTerm snf",
" | _ => raise ("^sname^".Run \"internal error in rewrite: strong failed\"))",
" | _ => (raise ("^sname^".Run \"internal error in rewrite: weak failed\"))",
" end",
"",
"val _ = "^sname^".set_compiled_rewriter rewrite",
"",
"end;"]
in
compiled_rewriter := NONE;
use_text ML_Context.local_context (1, "") false (!buffer);
case !compiled_rewriter of
NONE => raise (Compile "cannot communicate with compiled function")
| SOME r => (compiled_rewriter := NONE; r)
end
fun compile cache_patterns const_arity eqs =
let
val _ = if exists (fn (a,b,c) => not (null a)) eqs then raise Compile ("cannot deal with guards") else ()
val eqs = map (fn (a,b,c) => (b,c)) eqs
fun check (p, r) = if check_freevars (count_patternvars p) r then () else raise Compile ("unbound variables in rule")
val _ = map (fn (p, r) =>
(check (p, r);
case p of PVar => raise (Compile "pattern is just a variable") | _ => ())) eqs
in
load_rules "AM_Compiler" "AM_compiled_code" eqs
end
fun run prog t = (prog t)
fun discard p = ()
end