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In this changelog, we document "large-ish" changes to Iris that affect even the
way the logic is used on paper. We also mention some significant changes in the
Coq development, but not every API-breaking change is listed. Changes marked
`[#]` still need to be ported to the Iris Documentation LaTeX file(s).
Changes in and extensions of the theory:
* [#] CMRA morphisms have to be homomorphisms, not just monotone functions.
* [#] Show that f has a fixed point if f^k is contractive.
* Provide least and greatest fixed point (defined in the logic of Iris).
* Prove the inverse of wp_bind.
Changes in Coq:
* Some things got renamed and notation changed:
- The unit of a CMRA: empty -> unit, ∅ -> ε
- ?: IntoOp -> IsOp
- OFEs with all elements being discrete: Discrete -> OfeDiscrete
- OFE elements whose equality is discrete: Timeless -> Discrete
- Timeless propositions: TimelessP -> Timeless
- Camera elements such that `core x = x`: Persistent -> CoreId
- Persistent propositions: PersistentP -> Persistent
- The persistent modality: always -> persistently
- Consistently SnakeCase identifiers: CMRAMixin -> CmraMixin, CMRAT -> CmraT,
CMRATotal -> CmraTotal, CMRAMorphism -> CmraMorphism,
UCMRAMixin -> UcmraMixin, UCMRAT -> UcmraT, DRAMixin -> DraMixin,
DRAT -> DraT, STS -> Sts
- ? more
* Fix a bunch of consistency issues in the proof mode, and make it overall more
usable. In particular:
- All proof mode tactics start the proof mode if necessary; iStartProof is no
longer needed.
- Change in the grammar of specialization patterns: >[...] -> [> ...]
- ? More stuff ?
* Redefine bigops to get more definitional equalities.
* Improve solve_ndisj.
* Improve handling of pure (non-state-dependent) reductions in heap_lang.
* Use Hint Mode to prevent Coq from making arbitrary guesses in the presence of
evars. There are a few places where type annotations are now needed.
* The prelude folder has been moved to its own project: std++
* There now is a deprecation process. The modules `*.deprecated` contain
deprecated notations and definitions that are provided for backwards
compatibility and will be removed in a future version of Iris.
* View shifts are radically simplified to just internalize frame-preserving
updates. Weakestpre is defined inside the logic, and invariants and view
shifts with masks are also coded up inside Iris. Adequacy of weakestpre is
proven in the logic. The old ownership of the entire physical state is
replaced by a user-selected predicate over physical state that is maintained
by weakestpre.
* Use OFEs instead of COFEs everywhere. COFEs are only used for solving the
recursive domain equation. As a consequence, CMRAs no longer need a proof of
completeness. (The old `cofeT` is provided by `algebra.deprecated`.)
* Implement a new agreement construction. Unlike the old one, this one
preserves discreteness. dec_agree is thus no longer needed and has been moved
to algebra.deprecated.
* Renaming and moving things around: uPred and the rest of the base logic are in
`base_logic`, while `program_logic` is for everything involving the general
Iris notion of a language.
* Renaming in prelude.list: Rename `prefix_of` -> `prefix` and `suffix_of` ->
`suffix` in lemma names, but keep notation ``l1 `prefix_of` l2`` and ``l1
`suffix_of` l2``. `` l1 `sublist` l2`` becomes ``l1 `sublist_of` l2``. Rename
`contains` -> `submseteq` and change `` l1 `contains` l2`` to ``l1 ⊆+ l2``.
* Slightly weaker notion of atomicity: an expression is atomic if it reduces in
one step to something that does not reduce further.
* Changed notation for embedding Coq assertions into Iris. The new notation is
⌜φ⌝. Also removed `=` and `⊥` from the Iris scope. (The old notations are
provided in `base_logic.deprecated`.)
* Up-closure of namespaces is now a notation (↑) instead of a coercion.
* With invariants and the physical state being handled in the logic, there is no
longer any reason to demand the CMRA unit to be discrete.
* Local Updates (for the authoritative monoid) are now a 4-way relation with
syntax-directed lemmas proving them.
* [heap_lang] No longer use dependent types for expressions. Instead, values
carry a proof of closedness. Substitution, closedness and value-ness proofs
are performed by computation after reflecting into a term langauge that knows
about values and closed expressions.
* [program_logic/language] The language does not define its own "atomic"
predicate. Instead, atomicity is defined as reducing in one step to a value.
* [program_logic] Due to a lack of maintenance and usefulness, lifting lemmas
for Hoare triples are removed.
## Iris 2.0-rc2
* [algebra] Make the core of an RA or CMRA a partial function.
* [program_logic/lifting] Lifting lemmas no longer round-trip through a
user-chosen predicate to define the configurations we can reduce to; they
directly relate to the operational semantics. This is equivalent and
much simpler to read.
This is the Coq development and Iris Documentation as submitted to ICFP 2016.