quox/lib/Quox/Syntax/Term/Subst.idr

214 lines
6.8 KiB
Idris

module Quox.Syntax.Term.Subst
import Quox.Syntax.Term.Base
%default total
infixl 8 ///
mutual
namespace Term
||| does the minimal reasonable work:
||| - deletes the closure around an atomic constant like `TYPE`
||| - deletes an identity substitution
||| - composes (lazily) with an existing top-level dim-closure
||| - otherwise, wraps in a new closure
export
(///) : Term q dfrom n -> DSubst dfrom dto -> Term q dto n
s /// Shift SZ = s
TYPE l /// _ = TYPE l
DCloT s ph /// th = DCloT s $ ph . th
s /// th = DCloT s th
namespace Elim
private
subDArgs : Elim q dfrom n -> DSubst dfrom dto -> Elim q dto n
subDArgs (f :% d) th = subDArgs f th :% (d // th)
subDArgs e th = DCloE e th
||| does the minimal reasonable work:
||| - deletes the closure around a term variable
||| - deletes an identity substitution
||| - composes (lazily) with an existing top-level dim-closure
||| - immediately looks up bound variables in a
||| top-level sequence of dimension applications
||| - otherwise, wraps in a new closure
export
(///) : Elim q dfrom n -> DSubst dfrom dto -> Elim q dto n
e /// Shift SZ = e
F x /// _ = F x
B i /// _ = B i
f :% d /// th = subDArgs (f :% d) th
DCloE e ph /// th = DCloE e $ ph . th
e /// th = DCloE e th
namespace ScopeTermN
export
(///) : ScopeTermN s q dfrom n -> DSubst dfrom dto -> ScopeTermN s q dto n
TUsed body /// th = TUsed $ body /// th
TUnused body /// th = TUnused $ body /// th
namespace DScopeTermN
export
(///) : {s : Nat} ->
DScopeTermN s q dfrom n -> DSubst dfrom dto ->
DScopeTermN s q dto n
DUsed body /// th = DUsed $ body /// pushN s th
DUnused body /// th = DUnused $ body /// th
export %inline FromVar (Elim q d) where fromVar = B
export %inline FromVar (Term q d) where fromVar = E . fromVar
||| does the minimal reasonable work:
||| - deletes the closure around a *free* name
||| - deletes an identity substitution
||| - composes (lazily) with an existing top-level closure
||| - immediately looks up a bound variable
||| - otherwise, wraps in a new closure
export
CanSubst (Elim q d) (Elim q d) where
F x // _ = F x
B i // th = th !! i
CloE e ph // th = assert_total CloE e $ ph . th
e // th = case force th of
Shift SZ => e
th => CloE e th
||| does the minimal reasonable work:
||| - deletes the closure around an atomic constant like `TYPE`
||| - deletes an identity substitution
||| - composes (lazily) with an existing top-level closure
||| - goes inside `E` in case it is a simple variable or something
||| - otherwise, wraps in a new closure
export
CanSubst (Elim q d) (Term q d) where
TYPE l // _ = TYPE l
E e // th = E $ e // th
CloT s ph // th = CloT s $ ph . th
s // th = case force th of
Shift SZ => s
th => CloT s th
export %inline
{s : Nat} -> CanSubst (Elim q d) (ScopeTermN s q d) where
TUsed body // th = TUsed $ body // pushN s th
TUnused body // th = TUnused $ body // th
export %inline
{s : Nat} -> CanSubst (Elim q d) (DScopeTermN s q d) where
DUsed body // th = DUsed $ body // map (/// shift s) th
DUnused body // th = DUnused $ body // th
export %inline CanSubst Var (Term q d) where s // th = s // map (B {q, d}) th
export %inline CanSubst Var (Elim q d) where e // th = e // map (B {q, d}) th
export %inline
{s : Nat} -> CanSubst Var (ScopeTermN s q d) where
b // th = b // map (B {q, d}) th
export %inline
{s : Nat} -> CanSubst Var (DScopeTermN s q d) where
b // th = b // map (B {q, d}) th
infixl 8 //., ///
mutual
namespace Term
||| applies a term substitution with a less ambiguous type
export %inline
(//.) : Term q d from -> TSubst q d from to -> Term q d to
t //. th = t // th
||| applies a term and dimension substitution
public export %inline
subs : Term q dfrom from -> DSubst dfrom dto -> TSubst q dto from to ->
Term q dto to
subs s th ph = s /// th // ph
namespace Elim
||| applies a term substitution with a less ambiguous type
export %inline
(//.) : Elim q d from -> TSubst q d from to -> Elim q d to
e //. th = e // th
||| applies a term and dimension substitution
public export %inline
subs : Elim q dfrom from -> DSubst dfrom dto -> TSubst q dto from to ->
Elim q dto to
subs e th ph = e /// th // ph
namespace ScopeTermN
||| applies a term substitution with a less ambiguous type
export %inline
(//.) : {s : Nat} ->
ScopeTermN s q d from -> TSubst q d from to ->
ScopeTermN s q d to
body //. th = body // th
||| applies a term and dimension substitution
public export %inline
subs : {s : Nat} ->
ScopeTermN s q dfrom from ->
DSubst dfrom dto -> TSubst q dto from to ->
ScopeTermN s q dto to
subs body th ph = body /// th // ph
namespace DScopeTermN
||| applies a term substitution with a less ambiguous type
export %inline
(//.) : {s : Nat} -> DScopeTermN s q d from -> TSubst q d from to ->
DScopeTermN s q d to
body //. th = body // th
||| applies a term and dimension substitution
public export %inline
subs : {s : Nat} ->
DScopeTermN s q dfrom from ->
DSubst dfrom dto -> TSubst q dto from to ->
DScopeTermN s q dto to
subs body th ph = body /// th // ph
export %inline CanShift (Term q d) where s // by = s //. Shift by
export %inline CanShift (Elim q d) where e // by = e //. Shift by
export %inline
{s : Nat} -> CanShift (ScopeTermN s q d) where
b // by = b //. Shift by
export %inline
comp : DSubst dfrom dto -> TSubst q dfrom from mid -> TSubst q dto mid to ->
TSubst q dto from to
comp th ps ph = map (/// th) ps . ph
namespace ScopeTermN
export %inline
(.term) : {s : Nat} -> ScopeTermN s q d n -> Term q d (s + n)
(TUsed body).term = body
(TUnused body).term = body //. shift s
namespace DScopeTermN
export %inline
(.term) : {s : Nat} -> DScopeTermN s q d n -> Term q (s + d) n
(DUsed body).term = body
(DUnused body).term = body /// shift s
export %inline
sub1 : ScopeTerm q d n -> Elim q d n -> Term q d n
sub1 (TUsed body) e = body // one e
sub1 (TUnused body) e = body
export %inline
dsub1 : DScopeTerm q d n -> Dim d -> Term q d n
dsub1 (DUsed body) p = body /// one p
dsub1 (DUnused body) p = body
public export %inline
(.zero) : DScopeTerm q d n -> Term q d n
body.zero = dsub1 body $ K Zero
public export %inline
(.one) : DScopeTerm q d n -> Term q d n
body.one = dsub1 body $ K One