Rework on rich forms of rewrite

 1) changed the semantics of rewrite H,H' : the earlier semantics 
    (rewrite H,H' == rewrite H; rewrite H') was poorly suited for 
    situations where first rewrite H generates side-conditions. 
    New semantics is tclTHENFIRST instead of tclTHEN, that is
    side-conditions are left untouched. 

    Note to myself: check if side-effect-come-first bug of 
    setoid rewrite is still alive, and do something if yes

 2) new syntax for rewriting something many times. This syntax is 
    shamelessly taken from ssreflect: 

    rewrite ?H  means "H as many times as possible" 
      (i.e. almost repeat rewrite H, except that 
       possible side-conditions are left apart as in 1)
    rewrite !H  means "at least once" (i.e. rewrite H; repeat rewrite H)
    rewrite 3?H means "up to 3 times", maybe less 
      (i.e. something like: do 3 (try rewrite H)).
    rewrite 3!H means "exactly 3 times" (i.e. almost do 3 rewrite H).

    For instance:  rewrite 3?foo, <-2!bar in H1,H2|-*

 3) By the way, for a try, I've enabled the syntax +/- as synonyms for 
    ->/<- in the orientation of rewrite. 
   
   Comments welcome ...




git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@10612 85f007b7-540e-0410-9357-904b9bb8a0f7

1 files changed, 8 insertions, 1 deletions

diff --git a/proofs/tacexpr.ml b/proofs/tacexpr.ml
index 09d5c0516..a63fd1aeb 100644
--- a/proofs/tacexpr.ml
+++ b/proofs/tacexpr.ml
@@ -99,6 +99,12 @@ let simple_clause_of = function
   | { onhyps = Some []; onconcl = true; concl_occs=[] } -> None
   | _ -> error "not a simple clause (one hypothesis or conclusion)"
 
+type multi = 
+  | Precisely of int
+  | UpTo of int
+  | RepeatStar
+  | RepeatPlus
+
 type pattern_expr = constr_expr
 
 (* Type of patterns *)
@@ -187,7 +193,8 @@ type ('constr,'pat,'cst,'ind,'ref,'id,'tac) gen_atomic_tactic_expr =
   | TacTransitivity of 'constr 
 
   (* Equality and inversion *)
-  | TacRewrite of evars_flag * (bool * 'constr with_bindings) list * 'id gclause
+  | TacRewrite of 
+      evars_flag * (bool * multi * 'constr with_bindings) list * 'id gclause
   | TacInversion of ('constr,'id) inversion_strength * quantified_hypothesis
       
   (* For ML extensions *)