diff options
Diffstat (limited to 'plugins/setoid_ring')
-rw-r--r-- | plugins/setoid_ring/ArithRing.v | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/plugins/setoid_ring/ArithRing.v b/plugins/setoid_ring/ArithRing.v index 447acb905..8e4d8b0d3 100644 --- a/plugins/setoid_ring/ArithRing.v +++ b/plugins/setoid_ring/ArithRing.v @@ -41,9 +41,12 @@ Ltac Ss_to_add f acc := | _ => constr:((acc + f)%nat) end. +(* For internal use only *) +Local Definition protected_to_nat := N.to_nat. + Ltac natprering := match goal with - |- context C [S ?p] => + |- context C [S ?p] => match p with O => fail 1 (* avoid replacing 1 with 1+0 ! *) | p => match isnatcst p with @@ -52,9 +55,19 @@ Ltac natprering := fold v; natprering end end - | _ => idtac + | _ => change N.to_nat with protected_to_nat + end. + +Ltac natpostring := + match goal with + | |- context [N.to_nat ?x] => + let v := eval cbv in (N.to_nat x) in + change (N.to_nat x) with v; + natpostring + | _ => change protected_to_nat with N.to_nat end. Add Ring natr : natSRth - (morphism nat_morph_N, constants [natcst], preprocess [natprering]). + (morphism nat_morph_N, constants [natcst], + preprocess [natprering], postprocess [natpostring]). |