Giving a more natural semantics to injection by default.

There were three versions of injection:

1. "injection term" without "as" clause:
   was leaving hypotheses on the goal in reverse order
2. "injection term as ipat", first version:
   was introduction hypotheses using ipat in reverse order without
   checking that the number of ipat was the size of the injection
   (activated with "Unset Injection L2R Pattern Order")
3. "injection term as ipat", second version:
   was introduction hypotheses using ipat in left-to-right order
   checking that the number of ipat was the size of the injection
   and clearing the injecting term by default if an hypothesis
   (activated with "Set Injection L2R Pattern Order", default one from 8.5)

There is now:

4. "injection term" without "as" clause, new version:
   introducing the components of the injection in the context in
   left-to-right order using default intro-patterns "?"
   and clearing the injecting term by default if an hypothesis
   (activated with "Set Structural Injection")

The new versions 3. and 4. are the "expected" ones in the sense that
they have the following good properties:
- introduction in the context is in the natural left-to-right order
- "injection" behaves the same with and without "as", always
  introducing the hypotheses in the goal what corresponds to the
  natural expectation as the changes I made in the proof scripts for
  adaptation confirm
- clear the "injection" hypothesis when an hypothesis which is the
  natural expectation as the changes I made in the proof scripts for
  adaptation confirm

The compatibility can be preserved by "Unset Structural Injection" or
by calling "simple injection".

The flag is currently off.

1 files changed, 5 insertions, 5 deletions

diff --git a/theories/Strings/String.v b/theories/Strings/String.v
index 943bb48e9..451b65cbe 100644
--- a/theories/Strings/String.v
+++ b/theories/Strings/String.v
@@ -83,7 +83,7 @@ intros H; generalize (H 0); simpl; intros H1; inversion H1.
 case (Rec s).
 intros H0; rewrite H0; auto.
 intros n; exact (H (S n)).
-intros H; injection H; intros H1 H2 n; case n; auto.
+intros H; injection H as H1 H2.
 rewrite H2; trivial.
 rewrite H1; auto.
 Qed.
@@ -238,14 +238,14 @@ intros n m s1 s2; generalize n m s1; clear n m s1; elim s2; simpl;
  auto.
 intros n; case n; simpl; auto.
 intros m s1; case s1; simpl; auto.
-intros H; injection H; intros H1; rewrite <- H1; auto.
+intros H; injection H as <-; auto.
 intros; discriminate.
 intros; discriminate.
 intros b s2' Rec n m s1.
 case n; simpl; auto.
 generalize (prefix_correct s1 (String b s2'));
  case (prefix s1 (String b s2')).
-intros H0 H; injection H; intros H1; rewrite <- H1; auto.
+intros H0 H; injection H as <-; auto.
 case H0; simpl; auto.
 case m; simpl; auto.
 case (index 0 s1 s2'); intros; discriminate.
@@ -271,7 +271,7 @@ intros n m s1 s2; generalize n m s1; clear n m s1; elim s2; simpl;
  auto.
 intros n; case n; simpl; auto.
 intros m s1; case s1; simpl; auto.
-intros H; injection H; intros H1; rewrite <- H1.
+intros H; injection H as <-.
 intros p H0 H2; inversion H2.
 intros; discriminate.
 intros; discriminate.
@@ -279,7 +279,7 @@ intros b s2' Rec n m s1.
 case n; simpl; auto.
 generalize (prefix_correct s1 (String b s2'));
  case (prefix s1 (String b s2')).
-intros H0 H; injection H; intros H1; rewrite <- H1; auto.
+intros H0 H; injection H as <-; auto.
 intros p H2 H3; inversion H3.
 case m; simpl; auto.
 case (index 0 s1 s2'); intros; discriminate.