(* Title: Tools/Compute_Oracle/am_ghc.ML
Author: Steven Obua
*)
structure AM_GHC : ABSTRACT_MACHINE = struct
open AbstractMachine;
type program = string * string * (int Inttab.table)
fun count_patternvars PVar = 1
| count_patternvars (PConst (_, ps)) =
List.foldl (fn (p, count) => (count_patternvars p)+count) 0 ps
fun update_arity arity code a =
(case Inttab.lookup arity code of
NONE => Inttab.update_new (code, a) arity
| SOME (a': int) => if a > a' then Inttab.update (code, a) arity else arity)
(* We have to find out the maximal arity of each constant *)
fun collect_pattern_arity PVar arity = arity
| collect_pattern_arity (PConst (c, args)) arity = fold collect_pattern_arity args (update_arity arity c (length args))
local
fun collect applevel (Var _) arity = arity
| collect applevel (Const c) arity = update_arity arity c applevel
| collect applevel (Abs m) arity = collect 0 m arity
| collect applevel (App (a,b)) arity = collect 0 b (collect (applevel + 1) a arity)
in
fun collect_term_arity t arity = collect 0 t arity
end
fun nlift level n (Var m) = if m < level then Var m else Var (m+n)
| nlift level n (Const c) = Const c
| nlift level n (App (a,b)) = App (nlift level n a, nlift level n b)
| nlift level n (Abs b) = Abs (nlift (level+1) n b)
fun rep n x = if n = 0 then [] else x::(rep (n-1) x)
fun adjust_rules rules =
let
val arity = fold (fn (p, t) => fn arity => collect_term_arity t (collect_pattern_arity p arity)) rules Inttab.empty
fun arity_of c = the (Inttab.lookup arity c)
fun adjust_pattern PVar = PVar
| adjust_pattern (C as PConst (c, args)) = if (length args <> arity_of c) then raise Compile ("Constant inside pattern must have maximal arity") else C
fun adjust_rule (PVar, t) = raise Compile ("pattern may not be a variable")
| adjust_rule (rule as (p as PConst (c, args),t)) =
let
val _ = if not (check_freevars (count_patternvars p) t) then raise Compile ("unbound variables on right hand side") else ()
val args = map adjust_pattern args
val len = length args
val arity = arity_of c
fun lift level n (Var m) = if m < level then Var m else Var (m+n)
| lift level n (Const c) = Const c
| lift level n (App (a,b)) = App (lift level n a, lift level n b)
| lift level n (Abs b) = Abs (lift (level+1) n b)
val lift = lift 0
fun adjust_term n t = if n=0 then t else adjust_term (n-1) (App (t, Var (n-1)))
in
if len = arity then
rule
else if arity >= len then
(PConst (c, args @ (rep (arity-len) PVar)), adjust_term (arity-len) (lift (arity-len) t))
else (raise Compile "internal error in adjust_rule")
end
in
(arity, map adjust_rule rules)
end
fun print_term arity_of n =
let
fun str x = string_of_int x
fun protect_blank s = if exists_string Symbol.is_ascii_blank s then "(" ^ s ^")" else s
fun print_apps d f [] = f
| print_apps d f (a::args) = print_apps d ("app "^(protect_blank f)^" "^(protect_blank (print_term d a))) args
and print_call d (App (a, b)) args = print_call d a (b::args)
| print_call d (Const c) args =
(case arity_of c of
NONE => print_apps d ("Const "^(str c)) args
| SOME a =>
let
val len = length args
in
if a <= len then
let
val s = "c"^(str c)^(concat (map (fn t => " "^(protect_blank (print_term d t))) (List.take (args, a))))
in
print_apps d s (List.drop (args, a))
end
else
let
fun mk_apps n t = if n = 0 then t else mk_apps (n-1) (App (t, Var (n-1)))
fun mk_lambdas n t = if n = 0 then t else mk_lambdas (n-1) (Abs t)
fun append_args [] t = t
| append_args (c::cs) t = append_args cs (App (t, c))
in
print_term d (mk_lambdas (a-len) (mk_apps (a-len) (nlift 0 (a-len) (append_args args (Const c)))))
end
end)
| print_call d t args = print_apps d (print_term d t) args
and print_term d (Var x) = if x < d then "b"^(str (d-x-1)) else "x"^(str (n-(x-d)-1))
| print_term d (Abs c) = "Abs (\\b"^(str d)^" -> "^(print_term (d + 1) c)^")"
| print_term d t = print_call d t []
in
print_term 0
end
fun print_rule arity_of (p, t) =
let
fun str x = Int.toString x
fun print_pattern top n PVar = (n+1, "x"^(str n))
| print_pattern top n (PConst (c, [])) = (n, (if top then "c" else "C")^(str c))
| print_pattern top n (PConst (c, args)) =
let
val (n,s) = print_pattern_list (n, (if top then "c" else "C")^(str c)) args
in
(n, if top then s else "("^s^")")
end
and print_pattern_list r [] = r
| print_pattern_list (n, p) (t::ts) =
let
val (n, t) = print_pattern false n t
in
print_pattern_list (n, p^" "^t) ts
end
val (n, pattern) = print_pattern true 0 p
in
pattern^" = "^(print_term arity_of n t)
end
fun group_rules rules =
let
fun add_rule (r as (PConst (c,_), _)) groups =
let
val rs = (case Inttab.lookup groups c of NONE => [] | SOME rs => rs)
in
Inttab.update (c, r::rs) groups
end
| add_rule _ _ = raise Compile "internal error group_rules"
in
fold_rev add_rule rules Inttab.empty
end
fun haskell_prog name rules =
let
val buffer = Unsynchronized.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 (arity, rules) = adjust_rules rules
val rules = group_rules rules
val constants = Inttab.keys arity
fun arity_of c = Inttab.lookup arity c
fun rep_str s n = concat (rep n s)
fun indexed s n = s^(str n)
fun section n = if n = 0 then [] else (section (n-1))@[n-1]
fun make_show c =
let
val args = section (the (arity_of c))
in
" show ("^(indexed "C" c)^(concat (map (indexed " a") args))^") = "
^"\""^(indexed "C" c)^"\""^(concat (map (fn a => "++(show "^(indexed "a" a)^")") args))
end
fun default_case c =
let
val args = concat (map (indexed " x") (section (the (arity_of c))))
in
(indexed "c" c)^args^" = "^(indexed "C" c)^args
end
val _ = writelist [
"module "^name^" where",
"",
"data Term = Const Integer | App Term Term | Abs (Term -> Term)",
" "^(concat (map (fn c => " | C"^(str c)^(rep_str " Term" (the (arity_of c)))) constants)),
"",
"instance Show Term where"]
val _ = writelist (map make_show constants)
val _ = writelist [
" show (Const c) = \"c\"++(show c)",
" show (App a b) = \"A\"++(show a)++(show b)",
" show (Abs _) = \"L\"",
""]
val _ = writelist [
"app (Abs a) b = a b",
"app a b = App a b",
"",
"calc s c = writeFile s (show c)",
""]
fun list_group c = (writelist (case Inttab.lookup rules c of
NONE => [default_case c, ""]
| SOME (rs as ((PConst (_, []), _)::rs')) =>
if not (null rs') then raise Compile "multiple declaration of constant"
else (map (print_rule arity_of) rs) @ [""]
| SOME rs => (map (print_rule arity_of) rs) @ [default_case c, ""]))
val _ = map list_group constants
in
(arity, !buffer)
end
val guid_counter = Unsynchronized.ref 0
fun get_guid () =
let
val c = !guid_counter
val _ = guid_counter := !guid_counter + 1
in
(LargeInt.toString (Time.toMicroseconds (Time.now ()))) ^ (string_of_int c)
end
fun tmp_file s = Path.implode (Path.expand (File.tmp_path (Path.make [s])));
fun wrap s = "\""^s^"\""
fun writeTextFile name s = File.write (Path.explode name) s
val ghc = Unsynchronized.ref (case getenv "GHC_PATH" of "" => "ghc" | s => s)
fun fileExists name = ((OS.FileSys.fileSize name; true) handle OS.SysErr _ => false)
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
val guid = get_guid ()
val module = "AMGHC_Prog_"^guid
val (arity, source) = haskell_prog module eqs
val module_file = tmp_file (module^".hs")
val object_file = tmp_file (module^".o")
val _ = writeTextFile module_file source
val _ = system ((!ghc)^" -c "^module_file)
val _ = if not (fileExists object_file) then raise Compile ("Failure compiling haskell code (GHC_PATH = '"^(!ghc)^"')") else ()
in
(guid, module_file, arity)
end
fun readResultFile name = File.read (Path.explode name)
fun parse_result arity_of result =
let
val result = String.explode result
fun shift NONE x = SOME x
| shift (SOME y) x = SOME (y*10 + x)
fun parse_int' x (#"0"::rest) = parse_int' (shift x 0) rest
| parse_int' x (#"1"::rest) = parse_int' (shift x 1) rest
| parse_int' x (#"2"::rest) = parse_int' (shift x 2) rest
| parse_int' x (#"3"::rest) = parse_int' (shift x 3) rest
| parse_int' x (#"4"::rest) = parse_int' (shift x 4) rest
| parse_int' x (#"5"::rest) = parse_int' (shift x 5) rest
| parse_int' x (#"6"::rest) = parse_int' (shift x 6) rest
| parse_int' x (#"7"::rest) = parse_int' (shift x 7) rest
| parse_int' x (#"8"::rest) = parse_int' (shift x 8) rest
| parse_int' x (#"9"::rest) = parse_int' (shift x 9) rest
| parse_int' x rest = (x, rest)
fun parse_int rest = parse_int' NONE rest
fun parse (#"C"::rest) =
(case parse_int rest of
(SOME c, rest) =>
let
val (args, rest) = parse_list (the (arity_of c)) rest
fun app_args [] t = t
| app_args (x::xs) t = app_args xs (App (t, x))
in
(app_args args (Const c), rest)
end
| (NONE, rest) => raise Run "parse C")
| parse (#"c"::rest) =
(case parse_int rest of
(SOME c, rest) => (Const c, rest)
| _ => raise Run "parse c")
| parse (#"A"::rest) =
let
val (a, rest) = parse rest
val (b, rest) = parse rest
in
(App (a,b), rest)
end
| parse (#"L"::rest) = raise Run "there may be no abstraction in the result"
| parse _ = raise Run "invalid result"
and parse_list n rest =
if n = 0 then
([], rest)
else
let
val (x, rest) = parse rest
val (xs, rest) = parse_list (n-1) rest
in
(x::xs, rest)
end
val (parsed, rest) = parse result
fun is_blank (#" "::rest) = is_blank rest
| is_blank (#"\n"::rest) = is_blank rest
| is_blank [] = true
| is_blank _ = false
in
if is_blank rest then parsed else raise Run "non-blank suffix in result file"
end
fun run (guid, module_file, arity) t =
let
val _ = if check_freevars 0 t then () else raise Run ("can only compute closed terms")
fun arity_of c = Inttab.lookup arity c
val callguid = get_guid()
val module = "AMGHC_Prog_"^guid
val call = module^"_Call_"^callguid
val result_file = tmp_file (module^"_Result_"^callguid^".txt")
val call_file = tmp_file (call^".hs")
val term = print_term arity_of 0 t
val call_source = "module "^call^" where\n\nimport "^module^"\n\ncall = "^module^".calc \""^result_file^"\" ("^term^")"
val _ = writeTextFile call_file call_source
val _ = system ((!ghc)^" -e \""^call^".call\" "^module_file^" "^call_file)
val result = readResultFile result_file handle IO.Io _ => raise Run ("Failure running haskell compiler (GHC_PATH = '"^(!ghc)^"')")
val t' = parse_result arity_of result
val _ = OS.FileSys.remove call_file
val _ = OS.FileSys.remove result_file
in
t'
end
fun discard _ = ()
end