1. 29 Oct, 2018 2 commits
    • Jacques-Henri Jourdan's avatar
      wp_pures. · 2950fca6
      Jacques-Henri Jourdan authored
      2950fca6
    • Jacques-Henri Jourdan's avatar
      A specific constructor for injecting values in expressions · 9646293e
      Jacques-Henri Jourdan authored
      We add a specific constructor to the type of expressions for injecting
      values in expressions.
      
      The advantage are :
      - Values can be assumed to be always closed when performing
        substitutions (even though they could contain free variables, but it
        turns out it does not cause any problem in the proofs in
        practice). This means that we no longer need the `Closed` typeclass
        and everything that comes with it (all the reflection-based machinery
        contained in tactics.v is no longer necessary). I have not measured
        anything, but I guess this would have a significant performance
        impact.
      
      - There is only one constructor for values. As a result, the AsVal and
        IntoVal typeclasses are no longer necessary: an expression which is
        a value will always unify with `Val _`, and therefore lemmas can be
        stated using this constructor.
      
      Of course, this means that there are two ways of writing such a thing
      as "The pair of integers 1 and 2": Either by using the value
      constructor applied to the pair represented as a value, or by using
      the expression pair constructor. So we add reduction rules that
      transform reduced pair, injection and closure expressions into values.
      At first, this seems weird, because of the redundancy. But in fact,
      this has some meaning, since the machine migth actually be doing
      something to e.g., allocate the pair or the closure.
      
      These additional steps of computation show up in the proofs, and some
      additional wp_* tactics need to be called.
      9646293e
  2. 03 Jul, 2018 1 commit
  3. 17 May, 2018 1 commit
  4. 13 Jan, 2018 1 commit
  5. 25 Oct, 2017 1 commit
    • Robbert Krebbers's avatar
      Make `iDestruct ... as (cpat) "..."` work on '⌜φ⌝ ∧ P` and `⌜φ⌝ ∗ P`. · c5045145
      Robbert Krebbers authored
      The advantage is that we can directly use a Coq introduction pattern
      `cpat` to perform actions to the pure assertion. Before, this had
      to be done in several steps:
      
        iDestruct ... as "[Htmp ...]"; iDestruct "Htmp" as %cpat.
      
      That is, one had to introduce a temporary name.
      
      I expect this to be quite useful in various developments as many of
      e.g. our invariants are written as:
      
        ∃ x1 .. x2, ⌜ pure stuff ⌝ ∗ spacial stuff.
      c5045145
  6. 12 Jul, 2017 1 commit
  7. 05 Jan, 2017 1 commit
  8. 03 Jan, 2017 1 commit
  9. 09 Dec, 2016 3 commits
  10. 08 Dec, 2016 1 commit
  11. 22 Nov, 2016 1 commit
  12. 03 Nov, 2016 1 commit
    • Robbert Krebbers's avatar
      Use symbol ∗ for separating conjunction. · cc31476d
      Robbert Krebbers authored
      The old choice for ★ was a arbitrary: the precedence of the ASCII asterisk *
      was fixed at a wrong level in Coq, so we had to pick another symbol. The ★ was
      a random choice from a unicode chart.
      
      The new symbol ∗ (as proposed by David Swasey) corresponds better to
      conventional practise and matches the symbol we use on paper.
      cc31476d
  13. 27 Oct, 2016 1 commit
  14. 27 Sep, 2016 1 commit
  15. 05 Aug, 2016 2 commits
    • Robbert Krebbers's avatar
    • Robbert Krebbers's avatar
      Iris 3.0: invariants and weakest preconditions encoded in the logic. · 1f589858
      Robbert Krebbers authored
      This commit features:
      
      - A simpler model. The recursive domain equation no longer involves a triple
        containing invariants, physical state and ghost state, but just ghost state.
        Invariants and physical state are encoded using (higher-order) ghost state.
      
      - (Primitive) view shifts are formalized in the logic and all properties about
        it are proven in the logic instead of the model. Instead, the core logic
        features only a notion of raw view shifts which internalizing performing frame
        preserving updates.
      
      - A better behaved notion of mask changing view shifts. In particular, we no
        longer have side-conditions on transitivity of view shifts, and we have a
        rule for introduction of mask changing view shifts |={E1,E2}=> P with
        E2 ⊆ E1 which allows to postpone performing a view shift.
      
      - The weakest precondition connective is formalized in the logic using Banach's
        fixpoint. All properties about the connective are proven in the logic instead
        of directly in the model.
      
      - Adequacy is proven in the logic and uses a primitive form of adequacy for
        uPred that only involves raw views shifts and laters.
      
      Some remarks:
      
      - I have removed binary view shifts. I did not see a way to describe all rules
        of the new mask changing view shifts using those.
      - There is no longer the need for the notion of "frame shifting assertions" and
        these are thus removed. The rules for Hoare triples are thus also stated in
        terms of primitive view shifts.
      
      TODO:
      
      - Maybe rename primitive view shift into something more sensible
      - Figure out a way to deal with closed proofs (see the commented out stuff in
        tests/heap_lang and tests/barrier_client).
      1f589858
  16. 19 Jul, 2016 4 commits
  17. 18 Jul, 2016 1 commit