# HG changeset patch # User berghofe # Date 999267336 -7200 # Node ID 80acc6ce26c385a72554ed6bee88ddbd5f7d32b0 # Parent ae738c1ee155f3fa09b87c417eac1abbed3a7a69 Now obsolete; replaced by LF style proof terms. diff -r ae738c1ee155 -r 80acc6ce26c3 src/Pure/deriv.ML --- a/src/Pure/deriv.ML Fri Aug 31 16:14:34 2001 +0200 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,151 +0,0 @@ -(* Title: Pure/deriv.ML - ID: $Id$ - Author: Lawrence C Paulson, Cambridge University Computer Laboratory - Copyright 1996 University of Cambridge - -Derivations (proof objects) and functions for examining them -*) - -signature DERIV = - sig - (*Object-level rules*) - datatype orule = Subgoal of cterm - | Asm of int - | Res of deriv - | Equal of deriv - | Thm of string * tag list - | Other of deriv; - - val size : deriv -> int - val drop : 'a mtree * int -> 'a mtree - val linear : deriv -> deriv list - val tree : deriv -> orule mtree - end; - -structure Deriv : DERIV = -struct - -fun size (Join(Theorem _, _)) = 1 - | size (Join(_, ders)) = foldl op+ (1, map size ders); - -(*Conversion to linear format. Children of a node are the LIST of inferences - justifying ONE of the premises*) -fun rev_deriv (Join (rl, [])) = [Join(rl,[])] - | rev_deriv (Join (Theorem name, _)) = [Join(Theorem name, [])] - | rev_deriv (Join (Assumption arg, [der])) = - Join(Assumption arg,[]) :: rev_deriv der - | rev_deriv (Join (Bicompose arg, [rder, sder])) = - Join (Bicompose arg, linear rder) :: rev_deriv sder - | rev_deriv (Join (_, [der])) = rev_deriv der - | rev_deriv (Join (rl, der::ders)) = (*catch-all case; doubtful?*) - Join(rl, List.concat (map linear ders)) :: rev_deriv der -and linear der = rev (rev_deriv der); - - -(*** Conversion of object-level proof trees ***) - -(*Object-level rules*) -datatype orule = Subgoal of cterm - | Asm of int - | Res of deriv - | Equal of deriv - | Thm of string * tag list - | Other of deriv; - -(*At position i, splice in value x, removing ngoal elements*) -fun splice (i,x,ngoal,prfs) = - let val prfs0 = take(i-1,prfs) - and prfs1 = drop(i-1,prfs) - val prfs2 = Join (x, take(ngoal, prfs1)) :: drop(ngoal, prfs1) - in prfs0 @ prfs2 end; - -(*Deletes trivial uses of Equal_elim; hides derivations of Theorems*) -fun simp_deriv (Join (Equal_elim, [Join (Rewrite_cterm _, []), der])) = - simp_deriv der - | simp_deriv (Join (Equal_elim, [Join (Reflexive _, []), der])) = - simp_deriv der - | simp_deriv (Join (rule as Theorem name, [_])) = Join (rule, []) - | simp_deriv (Join (rule, ders)) = Join (rule, map simp_deriv ders); - -(*Proof term is an equality: first premise of equal_elim. - Attempt to decode proof terms made by Drule.goals_conv. - Subgoal numbers are returned; they are wrong if original subgoal - had flexflex pairs! - NEGATIVE i means "could affect all subgoals starting from i"*) -fun scan_equals (i, Join (Combination, - [Join (Combination, [_, der1]), der2])) = - (case der1 of (*ignore trivial cases*) - Join (Reflexive _, _) => scan_equals (i+1, der2) - | Join (Rewrite_cterm _, []) => scan_equals (i+1, der2) - | Join (Rewrite_cterm _, _) => (i,der1) :: scan_equals (i+1, der2) - | _ (*impossible in gconv*) => []) - | scan_equals (i, Join (Reflexive _, [])) = [] - | scan_equals (i, Join (Rewrite_cterm _, [])) = [] - (*Anything else could affect ALL following goals*) - | scan_equals (i, der) = [(~i,der)]; - -(*Record uses of equality reasoning on 1 or more subgoals*) -fun update_equals ((i,der), prfs) = - if i>0 then splice (i, Equal (simp_deriv der), 1, prfs) - else take (~i-1, prfs) @ - map (fn prf => Join (Equal (simp_deriv der), [prf])) - (drop (~i-1, prfs)); - -fun delift (Join (Lift_rule _, [der])) = der - | delift der = der; - -(*Conversion to an object-level proof tree. - Uses embedded Lift_rules to "annotate" the proof tree with subgoals; - -- assumes that Lift_rule never occurs except with resolution - -- may contain Vars that, in fact, are instantiated in that step*) -fun tree_aux (Join (Trivial ct, []), prfs) = Join(Subgoal ct, prfs) - | tree_aux (Join (Assumption(i,_), [der]), prfs) = - tree_aux (der, splice (i, Asm i, 0, prfs)) - | tree_aux (Join (Equal_elim, [der1,der2]), prfs) = - tree_aux (der2, foldr update_equals (scan_equals (1, der1), prfs)) - | tree_aux (Join (Bicompose (match,true,i,ngoal,env), ders), prfs) = - (*change eresolve_tac to proof by assumption*) - tree_aux (Join (Assumption(i, Some env), - [Join (Bicompose (match,false,i,ngoal,env), ders)]), - prfs) - | tree_aux (Join (Lift_rule (ct,i), [der]), prfs) = - tree_aux (der, splice (i, Subgoal ct, 1, prfs)) - | tree_aux (Join (Bicompose arg, - [Join (Instantiate _, [rder]), sder]), prfs) = - (*Ignore Instantiate*) - tree_aux (Join (Bicompose arg, [rder, sder]), prfs) - | tree_aux (Join (Bicompose arg, - [Join (Lift_rule larg, [rder]), sder]), prfs) = - (*Move Lift_rule: to make a Subgoal on the result*) - tree_aux (Join (Bicompose arg, [rder, - Join(Lift_rule larg, [sder])]), prfs) - | tree_aux (Join (Bicompose (match,ef,i,ngoal,env), - [Join (Bicompose (match',ef',i',ngoal',env'), - [der1,der2]), - der3]), prfs) = - (*associate resolutions to the right*) - tree_aux (Join (Bicompose (match', ef', i'+i-1, ngoal', env'), - [delift der1, (*This Lift_rule would be wrong!*) - Join (Bicompose (match, ef, i, ngoal-ngoal'+1, env), - [der2, der3])]), prfs) - | tree_aux (Join (Bicompose (arg as (_,_,i,ngoal,_)), - [rder, sder]), prfs) = - (*resolution with basic rule/assumption -- we hope!*) - tree_aux (sder, splice (i, Res (simp_deriv rder), ngoal, prfs)) - | tree_aux (Join (Theorem name, _), prfs) = Join(Thm name, prfs) - | tree_aux (Join (_, [der]), prfs) = tree_aux (der,prfs) - | tree_aux (der, prfs) = Join(Other (simp_deriv der), prfs); - - -fun tree der = tree_aux (der,[]); - -(*Currently declared at end, to avoid conflicting with library's drop - Can put it after "size" once we switch to List.drop*) -fun drop (der,0) = der - | drop (Join (_, der::_), n) = drop (der, n-1) - | drop (der,_) = der; - -end; - - -(*We do NOT open this structure*)