Summary:
The implementation in Context, in terms of Fol.Term and Fol.Formula,
can now be used instead of Ses.Equality, implemented using
Ses.Term. The Ses modules can now be removed.
Reviewed By: jvillard
Differential Revision: D24532362
fbshipit-source-id: cee9791b7
Summary:
Adapt the solver implementation from Ses.Equality to Context, and use
the interface of Fol.Context.
Reviewed By: jvillard
Differential Revision: D24532348
fbshipit-source-id: 2c6d41669
Summary:
Apply normalization to conditional terms similar to conditional
formulas: evaluate terms with literal conditions, equal branches, and
ensure the condition is not negative.
Reviewed By: jvillard
Differential Revision: D24532344
fbshipit-source-id: 7818dc496
Summary:
Operations over the core representation are more useful in the core
representation modules.
Reviewed By: ngorogiannis
Differential Revision: D24532340
fbshipit-source-id: f1eab822d
Summary:
The Fol.Term and Fol.Formula provide an interface which supports
if-then-else terms and formulas, while the underlying representation
in Trm does not and Fml only supports if-then-else over formulas, not
terms. The implementation of the rest of the first-order solver needs
to use the underlying, normalized, representation. This diff exports
Trm and Fml to separate modules for this purpose. Later, they will be
packed into a library for the first-order solver, and only used from
within.
Reviewed By: ngorogiannis
Differential Revision: D24532351
fbshipit-source-id: 7310827da
Summary:
And add Monad.Make to implement the full interface from return and
bind.
Reviewed By: ngorogiannis
Differential Revision: D24532341
fbshipit-source-id: 5740ba1c2
Summary:
The iterator is simpler to define and all the traversals are then
available through Iter.
Reviewed By: jvillard
Differential Revision: D24401743
fbshipit-source-id: 81f0653d9
Summary:
It is redundant to include the unit of conjunction in conjunction
formulas (resp., disjunction).
Reviewed By: jvillard
Differential Revision: D24371084
fbshipit-source-id: 6edc151e5
Summary: Simplify output of arithmetic terms, and omit trivial pure part of Sh.
Reviewed By: jvillard
Differential Revision: D24371082
fbshipit-source-id: 91f2117d3
Summary:
Normalization of literal formulas is determined by their term
arguments. Logically, this is part of the theories, so move this code
out of the Propositional module which is theory-independent and into
Fol, which is theory-sensitive.
Reviewed By: jvillard
Differential Revision: D24371081
fbshipit-source-id: f80a19ab8
Summary:
Change the type of `fold` functions to enable them to compose
better. The guiding reasoning behind using types such as:
```
val fold : 'a t -> 's -> f:('a -> 's -> 's) -> 's
```
is:
1. The function argument should be labeled. This is so that it can be
reordered relative to the others, since it is often a multi-line
`fun` expression.
2. The function argument should come last. This enables its
arguments (which are often polymorphic) to benefit from type-based
disambiguation information determined by the types of the other
arguments at the call sites.
3. The function argument's type should produce an
accumulator-transformer when partially-applied. That is,
`f x : 's -> 's`. This composes well with other functions designed
to produce transformers/endofunctions when partially applied, and
in particular improves the common case of composing folds into
"state-passing style" code.
4. The fold function itself should produce an accumulator-transformer
when partially applied. So `'a t -> 's -> f:_ -> 's` rather than
`'s -> 'a t -> f:_ -> 's` or `'a t -> init:'s -> f:_ -> 's` etc.
Reviewed By: jvillard
Differential Revision: D24306063
fbshipit-source-id: 13bd8bbee
Summary:
The changes in set_intf.ml dictate the rest. The previous API
minimized changes when changing the backing implementation. But that
API is hostile toward composition, partial application, and
state-passing style code.
Reviewed By: jvillard
Differential Revision: D24306089
fbshipit-source-id: 00a09f486
Summary:
Preceding commit reversed Map.to_iter to match the previous behavior
of to_list.
Reviewed By: jvillard
Differential Revision: D24306051
fbshipit-source-id: aad12e434
Summary:
The changes in map_intf.ml dictate the rest. The previous API
minimized changes when changing the backing implementation. But that
API is hostile toward composition, partial application, and
state-passing style code.
Reviewed By: jvillard
Differential Revision: D24306050
fbshipit-source-id: 71e286d4e
Summary:
The usage of equal_or_opposite boils down to evaluating formulas on
propositional constants, which seems clearer.
Reviewed By: jvillard
Differential Revision: D24306104
fbshipit-source-id: df5d07628
Summary:
Represent And and Or formulas as pairs of sets of formulas. One set is
interpreted as positive and the other as negative. This results in
normalization with respect to associativity, commutativity, and unit
laws. This does not normalize distributivity laws, e.g. formulas are
not expanded to disjunctive-normal form or conjunctive-normal
form. Additionally, "zero" laws P ∧ ¬P iff ⊥ and P ∨ ¬P iff ⊤ are
cheaply detected and normalized. Note that formulas are already in
negation-normal form.
Reviewed By: jvillard
Differential Revision: D24306072
fbshipit-source-id: e52265a44
Summary:
Expressing the sort of short-circuit evaluation in the changed code is
conceptually more direct using iterators.
Also, when using With_return, getting usable backtraces relies on the
compiler recognizing that the `raise` in the implementation of
`Base.Exn.raise_without_backtrace` should be a `reraise`. Using
iterators avoids this potential fragility.
Reviewed By: jvillard
Differential Revision: D24306094
fbshipit-source-id: b1abe04fb
Summary:
Change implementation of IArray from a wrapper of
Core_kernel.Array.Permissioned to NS.Array, and remove magic. Also
add operations to Array and Iter in order to ensure that IArray is an
extremely thin wrapper of Array: only defining conversions to/from
arrays as well as adding hashing support.
Reviewed By: jvillard
Differential Revision: D24306095
fbshipit-source-id: 97b9187be
Summary:
Term.const_of is misleading as it is easy to expect it checks if a
term is a constant, or to expect that it returns the constant part of
a term. Instead, Term.split_const is clearer:
```
val split_const : t -> t * Q.t
(** Splits a term into the sum of its constant and non-constant parts.
That is, [split_const a] is [(b, c)] such that [a = b + c] and the
absolute value of [c] is maximal. *)
```
Reviewed By: ngorogiannis
Differential Revision: D24306065
fbshipit-source-id: ba15958ad
Summary:
The treatment of comparison and exceptions in Core/Core_kernel/Base
makes them questionable as the default. This diff changes nonstdlib so
that Core is no longer opened in the global namespace, and makes a few
changes to handle the resulting minor API changes. This leads to a
lighter-touch nonstdlib, which makes a few definitions of its own, and
selects and extends modules from several libraries, including base,
core_kernel, containers, iter.
Reviewed By: jvillard
Differential Revision: D24306090
fbshipit-source-id: 42c91bd1b
Summary: Now elapsed time and the info in Unix.process_times is treated uniformly.
Reviewed By: jvillard
Differential Revision: D24306049
fbshipit-source-id: 09ab734ea
Summary:
The unary comparison to zero predicates are confusing to read since
whether the 0 is the left or right argument of the naturally infix
comparison is ambiguous. So replace Gt0 with Pos, meaning the argument
is positive, and remove the rest.
Reviewed By: jvillard
Differential Revision: D24306067
fbshipit-source-id: 2bd30dbe4
Summary:
Checking whether a formula is negative now only needs to inspect the
principle connective.
Reviewed By: ngorogiannis
Differential Revision: D24306061
fbshipit-source-id: 1f110e7f1
Summary:
Add a negation formula that will be used on atomic formulas instead of
ensuring the set of literals is closed under negation. This is in
preparation for more efficient negation and negation-normal form
preservation, which explicitly tracks whether literals are positive or
negative.
Reviewed By: ngorogiannis
Differential Revision: D24306055
fbshipit-source-id: 9300d6aee
Summary:
Change the representation of Fol terms to use polynomials for
arithmetic. This is a generalization and simplification of those used
in Ses. In particular, the treatment of division is stronger as it
captures associativity, commutativity, and unit laws, plus being the
inverse of multiplication.
Also, the interface is staged and factored so that the implementation
of polynomials and arithmetic is separate from the rest of terms.
Reviewed By: jvillard
Differential Revision: D24306108
fbshipit-source-id: 78589a8ec
Summary:
Function symbols when applied to literal values can be simplified by
evaluating them. This can be done even for function symbols that are
otherwise uninterpreted. This is not very strong, but is important in
some cases, and can prevent accumulating large complex terms that are
equal to literal constants.
Reviewed By: jvillard
Differential Revision: D24306044
fbshipit-source-id: 8c34d1ef2
Summary: In preparation for generalizing the type of multiplicities.
Reviewed By: jvillard
Differential Revision: D24306052
fbshipit-source-id: ddb71499e
Summary:
The form of the Base containers interface, in particular the way
comparison functions are passed using Comparators, is slower than
standard functors. Also Base.Map is missing some operations, such as
efficient merge and union.
Reviewed By: jvillard
Differential Revision: D24306047
fbshipit-source-id: e1623b693
Summary: Hopefully only transitional until Fol.Var and Ses.Var are conflated.
Reviewed By: jvillard
Differential Revision: D24306039
fbshipit-source-id: 5c3be8d4d
Summary:
Clarify the translation of 1-bit integer operations to formulas, and
add a few missing cases.
Reviewed By: ngorogiannis
Differential Revision: D24306057
fbshipit-source-id: 626a27997
Summary:
The translation from Llair to Fol can now be implemented using only
the external interface of Fol, so move it to a separate module. This
makes Fol not depend on Llair and vice versa, as appropriate.
Reviewed By: jvillard
Differential Revision: D24306087
fbshipit-source-id: fc68a588b
Summary:
Instead of relying on tuple terms, make function symbol applications
and predicate symbol literals n-ary directly.
Reviewed By: jvillard
Differential Revision: D24306078
fbshipit-source-id: 2863dceb4
Summary:
Move the punting between arrays and lists out of the clients of the
n-ary application normalizing constructors.
Reviewed By: jvillard
Differential Revision: D24306071
fbshipit-source-id: f3d2cb5df
Summary:
References from a record to one of its ancestor records are used to
represent cyclic or recursive record values. While the current
interpretation is weak, these logically are part of the record theory
and should be interpreted with the rest of the record terms.
Reviewed By: jvillard
Differential Revision: D24306091
fbshipit-source-id: 41553741d
Summary:
The empty record term is only used as the base of a sequence of
updates for an interval of indices from 0 to some N. A more direct
representation is to combine such sequences of updates into a flat
record term listing the elements.
Reviewed By: jvillard
Differential Revision: D24306048
fbshipit-source-id: d1b4900c8
Summary:
The uses of record terms only require indices that are literal
integers. This is a significant logical simplification from the
perspective of the backend solver.
Reviewed By: jvillard
Differential Revision: D24306093
fbshipit-source-id: 083dcc6b5
Summary:
Conversions between types are uninterpreted, so use uninterpreted
function symbols for them.
Reviewed By: jvillard
Differential Revision: D24306077
fbshipit-source-id: 49937fdbb
Summary:
Label values are uninterpreted, so use an uninterpreted function
symbol for them.
Reviewed By: jvillard
Differential Revision: D24306097
fbshipit-source-id: e139c70ba
Summary:
Floating point values are uninterpreted, so use an uninterpreted
function symbol for them.
Reviewed By: jvillard
Differential Revision: D24306096
fbshipit-source-id: 8c10dd3fd
Summary:
Convert from Llair.Exp to Fol.Term directly instead of going via
Ses.Term. This is a step on the way to removing Ses.
There are currently some term simplifications done in Ses.Term that
are missing in Fol.Term. This means that converting directly from
Llair.Exp to Fol.Term instead of via Ses.Term is not exactly the same
as the indirect conversion. The missing simplifications will be added
to Fol.Term in upcoming diffs.
Reviewed By: jvillard
Differential Revision: D24306053
fbshipit-source-id: 4ec5620a9
Summary:
Generalize Fol.Predsym to separate Predsym module for arbitrary
uninterpreted predicate symbols.
Add uninterpreted predicate literals to Ses.Term.
Use uninterpreted predicates to represent "ord" and "uno".
Reviewed By: jvillard
Differential Revision: D24306105
fbshipit-source-id: bdd72a8be
Summary: Funsym does not need to be defined as a submodule of Fol.
Reviewed By: jvillard
Differential Revision: D24306092
fbshipit-source-id: 7875f45f0
Summary:
A number of function symbols are not interpreted. This diff adds
generic uninterpreted function symbols, which will be used later to
avoid treating different uninterpreted functions separately.
Reviewed By: jvillard
Differential Revision: D24306076
fbshipit-source-id: b70ed10aa
Summary:
With the implementation of variables defined parametrically over their
representation, the implementation can also be used for Fol.Var.
Reviewed By: ngorogiannis
Differential Revision: D23703054
fbshipit-source-id: d27bdbbe8
Summary:
Variables are represented as a subtype of terms. The implementation of
the operations on variables is largely independent of this. This diff
generalizes the implementation over the concrete representation, and
moves it to a separate module.
Reviewed By: ngorogiannis
Differential Revision: D23660290
fbshipit-source-id: 90d8c3ca4
Josh Berdine