(* Title: HOL/Codatatype/Tools/bnf_fp_sugar_tactics.ML
Author: Jasmin Blanchette, TU Muenchen
Copyright 2012
Tactics for the LFP/GFP sugar.
*)
signature BNF_FP_SUGAR_TACTICS =
sig
val mk_case_tac: Proof.context -> int -> int -> int -> thm -> thm -> thm -> tactic
val mk_exhaust_tac: Proof.context -> int -> int list -> thm list -> thm -> thm -> tactic
val mk_fld_iff_unf_tac: Proof.context -> ctyp option list -> cterm -> cterm -> thm -> thm
-> tactic
val mk_half_distinct_tac: Proof.context -> thm -> thm list -> tactic
val mk_inject_tac: Proof.context -> thm -> thm -> tactic
end;
structure BNF_FP_Sugar_Tactics : BNF_FP_SUGAR_TACTICS =
struct
open BNF_Tactics
open BNF_Util
fun mk_case_tac ctxt n k m case_def ctr_def unf_fld =
Local_Defs.unfold_tac ctxt [case_def, ctr_def, unf_fld] THEN
(rtac (BNF_FP_Util.mk_sum_casesN n k RS ssubst) THEN'
REPEAT_DETERM_N (Int.max (0, m - 1)) o rtac (@{thm split} RS ssubst) THEN'
rtac refl) 1;
fun mk_exhaust_tac ctxt n ms ctr_defs fld_iff_unf sumEN' =
Local_Defs.unfold_tac ctxt (fld_iff_unf :: ctr_defs) THEN rtac sumEN' 1 THEN
Local_Defs.unfold_tac ctxt @{thms all_prod_eq} THEN
EVERY' (map2 (fn k => fn m => select_prem_tac n (REPEAT_DETERM_N m o dtac @{thm meta_spec} THEN'
etac @{thm meta_mp}) k THEN' atac) (1 upto n) ms) 1;
fun mk_fld_iff_unf_tac ctxt cTs cfld cunf fld_unf unf_fld =
(rtac iffI THEN'
EVERY' (map3 (fn cTs => fn cx => fn th =>
dtac (Drule.instantiate' cTs [NONE, NONE, SOME cx] arg_cong) THEN'
SELECT_GOAL (Local_Defs.unfold_tac ctxt [th]) THEN'
atac) [rev cTs, cTs] [cunf, cfld] [unf_fld, fld_unf])) 1;
fun mk_half_distinct_tac ctxt fld_inject ctr_defs =
Local_Defs.unfold_tac ctxt (fld_inject :: @{thms sum.inject} @ ctr_defs) THEN
rtac @{thm sum.distinct(1)} 1;
fun mk_inject_tac ctxt ctr_def fld_inject =
Local_Defs.unfold_tac ctxt [ctr_def] THEN rtac (fld_inject RS ssubst) 1 THEN
Local_Defs.unfold_tac ctxt @{thms sum.inject Pair_eq conj_assoc} THEN rtac refl 1;
end;