Nola: Parameterizing Higher-Order Ghost State to Clear the Later Modality

Nola is a library for parameterizing higher-order ghost state, which enables wiping out the later modality. It is fully mechanized in Coq with the Iris separation logic framework.

The name Nola comes from 'No later' and the nickname for New Orleans, Louisiana, US.

• Publication
• Getting Started
• Architecture

Publication

• Non-Step-Indexed Separation Logic with Invariants and Rust-Style Borrows. Yusuke Matsushita. Ph.D. Thesis, University of Tokyo. Dec 2023. Paper Talk slides

Getting Started

We use opam ver 2.* for package management.

To set up an opam switch named nola and link it to the folder:

opam switch create nola 5.0.0 # Choose an OCaml version
opam switch link nola .

To set up opam repos for Coq and Iris for the current opam switch:

opam repo add coq-released https://coq.inria.fr/opam/released
opam repo add iris-dev https://gitlab.mpi-sws.org/iris/opam.git

To fix development dependencies and compile Coq code:

make devdep
make -j16 # Choose a job number

Or to install as a library locally:

opam install .

To generate and browse a document:

make viewdoc

Architecture

All the Coq code is in nola/ and structured as follows:

• prelude : Prelude
• util/ : General-purpose utilities, extending stdpp
  • eq (Equality),
  • uip (UIP)
  • gmap (On gmap), gmultiset (On gmultiset)
  • prod (Modified product), plist (Product list)
  • proph (Prophecy)
  • sem (Semantics)
  • order (Order theory), psg (Pseudo-gfp)
  • productive (Productivity)
  • nary (N-ary maps), cit (Coinductive-inductive tree)
• bi/ : Libraries for bunched implication logic
  • util (Utilities)
  • later (Later modality)
  • gmap (On gmap), plist (On plist)
  • order (Order theory), deriv (Derivability)
  • genupd (General update), updw (Update with a custom world satisfaction), wpw (Weakest precondition with a custom world satisfaction)
  • paradox (Paradoxes)
• iris/ : Libraries for Iris base logic
  • iprop (iprop)
  • own (On own)
  • list (On lists)
  • option (On option), agree (On agree), csum (On csum)
  • sinv (Simple invariant), sinv_deriv (Simple invariant relaxed with derivability)
  • inv (Invariant), inv_deriv (Invariant relaxed with derivability), na_inv (Non-atomic invariant), na_inv_deriv (Non-atomic invariant relaxed with derivability)
  • lft (Lifetime), borrow (Borrowing), borrow_deriv (Borrowing relaxed with derivability)
  • proph (Prophecy), proph_ag (Prophetic agreement), pborrow (Prophetic borrowing)
  • cif (Coinductive-inductive formula)
• heap_lang/ : Variant of Iris HeapLang, supporting Ndnat (infinite non-determinism) and program logic with custom world satisfactions
  • lib/ : Libraries
    • mutex (Mutex machinery)
• examples/ : Examples
  • logic (Logic)