(* Title: HOL/BNF/Tools/bnf_fp_rec_sugar_util.ML
Author: Lorenz Panny, TU Muenchen
Author: Jasmin Blanchette, TU Muenchen
Copyright 2013
Library for recursor and corecursor sugar.
*)
signature BNF_FP_REC_SUGAR_UTIL =
sig
val indexed: 'a list -> int -> int list * int
val indexedd: 'a list list -> int -> int list list * int
val indexeddd: 'a list list list -> int -> int list list list * int
val indexedddd: 'a list list list list -> int -> int list list list list * int
val find_index_eq: ''a list -> ''a -> int
val finds: ('a * 'b -> bool) -> 'a list -> 'b list -> ('a * 'b list) list * 'b list
val drop_All: term -> term
val mk_partial_compN: int -> typ -> term -> term
val mk_partial_comp: typ -> typ -> term -> term
val mk_compN: int -> typ list -> term * term -> term
val mk_comp: typ list -> term * term -> term
val get_indices: ((binding * typ) * 'a) list -> term -> int list
end;
structure BNF_FP_Rec_Sugar_Util : BNF_FP_REC_SUGAR_UTIL =
struct
fun indexed xs h = let val h' = h + length xs in (h upto h' - 1, h') end;
fun indexedd xss = fold_map indexed xss;
fun indexeddd xsss = fold_map indexedd xsss;
fun indexedddd xssss = fold_map indexeddd xssss;
fun find_index_eq hs h = find_index (curry (op =) h) hs;
fun finds eq = fold_map (fn x => List.partition (curry eq x) #>> pair x);
fun drop_All t =
subst_bounds (strip_qnt_vars @{const_name all} t |> map Free |> rev,
strip_qnt_body @{const_name all} t);
fun mk_partial_comp gT fT g =
let val T = domain_type fT --> range_type gT in
Const (@{const_name Fun.comp}, gT --> fT --> T) $ g
end;
fun mk_partial_compN 0 _ g = g
| mk_partial_compN n fT g =
let val g' = mk_partial_compN (n - 1) (range_type fT) g in
mk_partial_comp (fastype_of g') fT g'
end;
fun mk_compN n bound_Ts (g, f) =
let val typof = curry fastype_of1 bound_Ts in
mk_partial_compN n (typof f) g $ f
end;
val mk_comp = mk_compN 1;
fun get_indices fixes t = map (fst #>> Binding.name_of #> Free) fixes
|> map_index (fn (i, v) => if exists_subterm (equal v) t then SOME i else NONE)
|> map_filter I;
end;