Proof_using: new syntax + suggestion

Proof using can be followed by:
- All : all variables
- Type : all variables occurring in the type
- expr:
    - (a b .. c) : set
    - expr + expr : set union
    - expr - expr : set difference
    - -expr : set complement (All - expr)
Exceptions:
- a singleton set can be written without parentheses. This also allows
  the implementation of named sets sharing the same name space of
  section hyps ans write
  - bla - x : where bla is defined as (a b .. x y) elsewhere.
- if expr is just a set, then parentheses can be omitted

This module also implements some AI to tell the user how he could
decorate "Proof" with a "using BLA" clause.

Finally, one can Set Default Proof Using "str" to any string that is
used whenever the "using ..." part is missing.  The coding of this
sucks a little since it is the parser that applies the default.

1 files changed, 1 insertions, 0 deletions

diff --git a/proofs/proofs.mllib b/proofs/proofs.mllib
index 4a7efb029..96b9a89a3 100644
--- a/proofs/proofs.mllib
+++ b/proofs/proofs.mllib
@@ -1,5 +1,6 @@
 Goal
 Evar_refiner
+Proof_using
 Proof_type
 Proof_errors
 Proofview_gen