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use super::*;
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
pub struct FunctionalLinearity {
dependency: Dependency,
linearity: Linearity,
call_usage: Usage,
}
impl FunctionalLinearity {
pub const USED: FunctionalLinearity = FunctionalLinearity::covar(Usage::USED);
pub const CONTRADICTION: FunctionalLinearity = FunctionalLinearity {
dependency: Dependency::CONTRADICTION,
linearity: Linearity::LINEAR,
call_usage: Usage::CONSUMED,
};
#[inline]
pub const fn covar(arg_usage: Usage) -> FunctionalLinearity {
FunctionalLinearity {
dependency: Dependency::covar(arg_usage),
linearity: Linearity::NONLINEAR,
call_usage: Usage::OBSERVED,
}
}
#[inline]
pub const fn new(
dependency: Dependency,
linearity: Linearity,
call_usage: Usage,
) -> FunctionalLinearity {
let call_usage = call_usage.meet(linearity.max_usage());
FunctionalLinearity {
dependency,
linearity,
call_usage,
}.unify_contr()
}
#[inline]
pub const fn id(linearity: Linearity) -> FunctionalLinearity {
FunctionalLinearity {
dependency: Dependency::covar(linearity.max_usage()),
linearity,
call_usage: Usage::OBSERVED,
}
}
#[inline]
pub const fn const_fn(linearity: Linearity) -> FunctionalLinearity {
FunctionalLinearity {
dependency: Dependency::NULL,
linearity,
call_usage: linearity.max_usage(),
}
}
#[inline]
const fn unify_contr(self) -> FunctionalLinearity {
if self.dependency.relationship.is_contradiction() {
FunctionalLinearity::CONTRADICTION
} else {
self
}
}
#[inline]
pub const fn dependency(self) -> Dependency {
self.dependency
}
#[inline]
pub const fn linearity(self) -> Linearity {
self.linearity
}
#[inline]
pub const fn call_usage(self) -> Usage {
self.call_usage
}
#[inline]
pub const fn max_usage(self) -> Usage {
self.linearity.max_usage()
}
#[inline]
pub fn of_arg(self, arg: &SymbolId) -> FunctionalLinearity {
FunctionalLinearity {
dependency: self.dependency.of(arg),
..self
}
}
#[inline]
pub const fn const_cmp(self, other: FunctionalLinearity) -> Result<Ordering, Error> {
let linearity_ord = if let Some(linearity_ord) = self.linearity.const_cmp(other.linearity) {
linearity_ord
} else {
return Err(Error::IncompatibleTypeLinearity(
self.linearity,
other.linearity,
));
};
let call_ord = if let Some(call_ord) = self.call_usage.const_cmp(other.call_usage) {
call_ord
} else {
return Err(Error::IncompatibleCallUsage(
self.call_usage,
other.call_usage,
));
};
let dependency_ord =
if let Some(dependency_ord) = self.dependency.const_cmp(other.dependency) {
dependency_ord.reverse()
} else {
return Err(Error::IncompatibleRelationships(
self.dependency.relationship,
other.dependency.relationship,
));
};
if let Some(ord) =
lattice_ord_opt(lattice_ord(linearity_ord, call_ord), Some(dependency_ord))
{
Ok(ord)
} else {
Err(Error::IncompatibleLinearity(None))
}
}
#[inline]
pub fn iter_all() -> impl Iterator<Item = FunctionalLinearity> {
Dependency::iter_all()
.map(move |dependency| {
Linearity::LINEARITIES
.iter()
.copied()
.map(move |linearity| {
Usage::USAGES
.iter()
.copied()
.map(move |call_usage| FunctionalLinearity {
dependency,
linearity,
call_usage,
})
})
.flatten()
})
.flatten()
}
}
impl PartialOrd for FunctionalLinearity {
#[inline]
fn partial_cmp(&self, other: &FunctionalLinearity) -> Option<Ordering> {
self.const_cmp(*other).ok()
}
}
#[derive(Clone, Eq)]
pub struct Pi {
arg: SymbolId,
result: ValId,
linearity: FunctionalLinearity,
ty: ValId,
fv: SymbolSet,
is_indep: bool,
code: u64,
}
impl Debug for Pi {
fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
if self.is_indep {
write!(
fmt,
"Pi({:?} => {:?}, {:?})",
self.arg.ty(),
self.result,
self.linearity
)
} else {
fmt.debug_struct("Pi")
.field("arg", &self.arg)
.field("result", &self.result)
.field("lin", &self.linearity)
.finish()
}
}
}
impl PartialEq for Pi {
fn eq(&self, other: &Pi) -> bool {
if self.code != other.code
|| self.linearity != other.linearity
|| self.is_indep != other.is_indep
{
return false;
}
match self.is_indep {
true => self.arg.ty() == other.arg.ty() && self.result == other.result,
false => self.arg == other.arg && self.result == other.result,
}
}
}
impl Hash for Pi {
#[inline]
fn hash<H: Hasher>(&self, hasher: &mut H) {
if self.is_indep {
self.arg.ty().hash(hasher)
} else {
self.arg.hash(hasher);
}
self.result.hash(hasher);
}
}
impl Pi {
pub fn try_new(
arg: SymbolId,
result: ValId,
linearity: FunctionalLinearity,
) -> Result<Pi, Error> {
if !result.is_ty() {
return Err(Error::NotAType);
}
let linearity = linearity.of_arg(&arg);
let ty = SET.clone();
let mut fv = arg.ty().fv().union(result.fv());
let is_indep = fv.remove(&arg).is_none();
let mut result = Pi {
arg,
result,
fv,
ty,
is_indep,
code: 0,
linearity,
};
result.update_code();
Ok(result)
}
pub fn result(&self) -> &ValId {
&self.result
}
pub fn arg(&self) -> &SymbolId {
&self.arg
}
pub fn arg_ty(&self) -> &ValId {
self.arg.ty()
}
pub fn unary(ty: ValId, linearity: FunctionalLinearity) -> Result<Pi, Error> {
let arg = SymbolId::param(ty.clone())?;
Self::try_new(arg, ty, linearity)
}
pub fn binary(ty: ValId, linearity: FunctionalLinearity) -> Result<Pi, Error> {
let arg = SymbolId::param(ty.clone())?;
let unary = Self::try_new(arg.clone(), ty, linearity)?.into_valid();
Self::try_new(arg, unary, linearity)
}
#[inline]
pub fn is_indep(&self) -> bool {
self.is_indep
}
#[inline]
fn update_code(&mut self) {
let mut hasher = Self::get_hasher();
let arg_code = if self.is_indep {
self.arg.ty().code()
} else {
self.arg.code()
};
arg_code.hash(&mut hasher);
self.result.hash(&mut hasher);
self.code = hasher.finish();
}
#[inline]
pub fn get_hasher() -> AHasher {
AHasher::new_with_keys(0, 1)
}
pub fn invar_eq(&self, other: &Pi) -> bool {
match self.is_indep {
true => self.arg.ty() == other.arg.ty() && self.result == other.result,
false => self.arg == other.arg && self.result == other.result,
}
}
#[inline]
pub fn subtype_pi(&self, other: &Pi, variance: Variance) -> Result<Match, Error> {
if variance == Contravariant {
return other.subtype_pi(self, Covariant);
}
if variance == Bivariant {
return self
.subtype_pi(other, Covariant)
.or_else(|_| other.subtype_pi(self, Covariant));
}
let linearity_cmp = self.linearity.const_cmp(other.linearity)?;
if !variance.matches_ord(linearity_cmp) {
return Err(Error::WrongLinearityOrder);
}
if self.invar_eq(other) {
return Ok(Match::dependency(self.linearity.call_usage()));
}
unimplemented!()
}
#[inline]
pub fn fun_lin(&self) -> FunctionalLinearity {
self.linearity
}
#[inline]
pub fn call_relationship(&self) -> Relationship {
Relationship::dependency(self.linearity.call_usage())
}
}
impl Value for Pi {
#[inline]
fn ty(&self) -> &ValId {
&self.ty
}
#[inline]
fn is_groupoid(&self) -> bool {
false
}
#[inline]
fn is_ty(&self) -> bool {
true
}
#[inline]
fn is_kind(&self) -> bool {
false
}
#[inline]
fn into_enum(self) -> ValueEnum {
ValueEnum::Pi(self)
}
#[inline]
fn fv(&self) -> &SymbolSet {
&self.fv
}
#[inline]
fn code(&self) -> u64 {
self.code
}
fn contains(&self, other: &ValId) -> Result<Match, Error> {
self.subtype(other.ty(), Covariant)
}
#[inline]
fn subtype(&self, other: &ValId, variance: Variance) -> Result<Match, Error> {
match other.as_enum() {
ValueEnum::Pi(pi) => self.subtype_pi(pi, variance),
_ => Err(Error::TypeMismatch),
}
}
fn eval_in_ctx(&self, ctx: &mut EvalCtx) -> Option<ValId> {
if ctx.is_empty() {
return None;
}
let new_arg = self.arg.new_in_ctx(ctx);
let mut ctx_tmp;
let (arg, ctx) = if let Some(arg) = new_arg {
if self.is_indep() {
(Some(arg), ctx)
} else {
ctx_tmp = ctx.added_unchecked(self.arg.clone(), arg.clone().into_valid())
.expect("Adding a new symbol with a guaranteed new definition always results in a change");
(Some(arg), &mut ctx_tmp)
}
} else if let Some(removed) = ctx.removed(&self.arg) {
ctx_tmp = removed;
(None, &mut ctx_tmp)
} else {
(None, ctx)
};
let result = self.result().eval_in_ctx(ctx);
let (arg, result) = match (arg, result) {
(None, None) => return None,
(Some(arg), None) => (arg, self.result.clone()),
(None, Some(result)) => (self.arg.clone(), result),
(Some(arg), Some(result)) => (arg, result),
};
let pi = Pi::try_new(arg, result, self.linearity)
.expect("Substituted pi construction should never fail");
Some(pi.into_valid())
}
fn apply_ty_in_ctx(&self, arg: &ValId, ctx: &mut EvalCtx) -> Result<Abstract, Error> {
let mut ctx_tmp;
let (match_, ctx_ref) = if !self.is_indep {
let (match_, c) = ctx.added(self.arg.clone(), arg.clone())?;
if let Some(c) = c {
ctx_tmp = c;
(match_, &mut ctx_tmp)
} else {
(match_, ctx)
}
} else {
let match_ = self.arg.match_symbol(arg)?;
(match_, ctx)
};
let ty = self
.result
.eval_in_ctx(ctx_ref)
.unwrap_or_else(|| self.result.clone());
let abs = Abstract {
ty,
constraints: match_.into_constraints(None, Some(arg.clone())),
relationship: self.call_relationship(),
};
Ok(abs)
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn functional_linearity_partial_ord() {
for linearity in FunctionalLinearity::iter_all() {
assert!(
linearity <= FunctionalLinearity::CONTRADICTION,
"{:#?} <= {:#?}",
linearity,
FunctionalLinearity::CONTRADICTION
);
}
}
#[test]
fn basic_unary_bool_properties() {
let unary = Pi::unary(Bool.into_valid(), FunctionalLinearity::USED)
.unwrap()
.into_valid();
assert_eq!(
unary.apply_ty(&*FALSE).unwrap(),
Abstract::used(Bool.into_valid()).unwrap()
);
assert_eq!(unary.apply_ty(&*NAT), Err(Error::TypeMismatch));
assert_eq!(unary.apply(&*TRUE), Err(Error::NotAFunctionType));
}
}