diff -r 000000000000 -r a5a9c433f639 src/Provers/ind.ML --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/Provers/ind.ML Thu Sep 16 12:20:38 1993 +0200 @@ -0,0 +1,65 @@ +(* Title: Provers/ind + ID: $Id$ + Author: Tobias Nipkow + Copyright 1991 University of Cambridge + +Generic induction package -- for use with simplifier +*) + +signature IND_DATA = + sig + val spec: thm (* All(?P) ==> ?P(?a) *) + end; + + +signature IND = + sig + val all_frees_tac: string -> int -> tactic + val ALL_IND_TAC: thm -> (int -> tactic) -> (int -> tactic) + val IND_TAC: thm -> (int -> tactic) -> string -> (int -> tactic) + end; + + +functor InductionFun(Ind_Data: IND_DATA):IND = +struct +local open Ind_Data in + +val _$(_$Var(a_ixname,aT)) = concl_of spec; +val a_name = implode(tl(explode(Syntax.string_of_vname a_ixname))); + +fun add_term_frees tsig = +let fun add(tm, vars) = case tm of + Free(v,T) => if Type.typ_instance(tsig,T,aT) then v ins vars + else vars + | Abs (_,_,body) => add(body,vars) + | rator$rand => add(rator, add(rand, vars)) + | _ => vars +in add end; + + +fun qnt_tac i = fn (tac,var) => tac THEN res_inst_tac [(a_name,var)] spec i; + +(*Generalizes over all free variables, with the named var outermost.*) +fun all_frees_tac (var:string) i = Tactic(fn thm => + let val tsig = #tsig(Sign.rep_sg(#sign(rep_thm thm))); + val frees = add_term_frees tsig (nth_elem(i-1,prems_of thm),[var]); + val frees' = sort(op>)(frees \ var) @ [var] + in tapply(foldl (qnt_tac i) (all_tac,frees'), thm) end); + +fun REPEAT_SIMP_TAC simp_tac n i = +let fun repeat thm = tapply(COND (has_fewer_prems n) all_tac + let val k = length(prems_of thm) + in simp_tac i THEN COND (has_fewer_prems k) (Tactic repeat) all_tac + end, thm) +in Tactic repeat end; + +fun ALL_IND_TAC sch simp_tac i = Tactic(fn thm => tapply( + resolve_tac [sch] i THEN + REPEAT_SIMP_TAC simp_tac (length(prems_of thm)) i, thm)); + +fun IND_TAC sch simp_tac var = + all_frees_tac var THEN' ALL_IND_TAC sch simp_tac; + + +end +end;