1. 26 Sep, 2017 1 commit
    • Robbert Krebbers's avatar
      Fix issue #98. · e17ac4ad
      Robbert Krebbers authored
      We used to normalize the goal, and then checked whether it was of
      a certain shape. Since `uPred_valid P` normalized to `True ⊢ P`,
      there was no way of making a distinction between the two, hence
      `True ⊢ P` was treated as `uPred_valid P`.
      
      In this commit, I use type classes to check whether the goal is of
      a certain shape. Since we declared `uPred_valid` as `Typeclasses
      Opaque`, we can now make a distinction between `True ⊢ P` and
      `uPred_valid P`.
      e17ac4ad
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  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. 01 Nov, 2016 1 commit
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  15. 25 Oct, 2016 2 commits
    • Robbert Krebbers's avatar
      Generalize update tactics into iMod and iModIntro for modalities. · fc30ca08
      Robbert Krebbers authored
      There are now two proof mode tactics for dealing with modalities:
      
      - `iModIntro` : introduction of a modality
      - `iMod pm_trm as (x1 ... xn) "ipat"` : eliminate a modality
      
      The behavior of these tactics can be controlled by instances of the `IntroModal`
      and `ElimModal` type class. We have declared instances for later, except 0,
      basic updates and fancy updates. The tactic `iMod` is flexible enough that it
      can also eliminate an updates around a weakest pre, and so forth.
      
      The corresponding introduction patterns of these tactics are `!>` and `>`.
      
      These tactics replace the tactics `iUpdIntro`, `iUpd` and `iTimeless`.
      
      Source of backwards incompatability: the introduction pattern `!>` is used for
      introduction of arbitrary modalities. It used to introduce laters by stripping
      of a later of each hypotheses.
      fc30ca08
    • Robbert Krebbers's avatar
      Rename rvs -> bupd (basic update), pvs -> fupd (fancy update). · 1b85d654
      Robbert Krebbers authored
      And also rename the corresponding proof mode tactics.
      1b85d654
  16. 06 Oct, 2016 1 commit
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  20. 05 Aug, 2016 4 commits
    • Robbert Krebbers's avatar
      A nicer version of adequacy of Iris and specialize it to heap_lang. · 5ee10883
      Robbert Krebbers authored
      Use it to prove that tests/barrier_client and tests/heap_lang are adequate.
      5ee10883
    • Robbert Krebbers's avatar
    • Robbert Krebbers's avatar
      More introduction patterns. · 4d8c4ac8
      Robbert Krebbers authored
      Also make those for introduction and elimination more symmetric:
      
        !%   pure introduction         %        pure elimination
        !#   always introduction       #        always elimination
        !>   later introduction        > pat    timeless later elimination
        !==> view shift introduction   ==> pat  view shift elimination
      4d8c4ac8
    • 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
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