Safe Haskell	Safe-Inferred

DDC.Source.Tetra.Exp

Contents

Expressions
Witnesses
Data Constructors
Witness Constructors

Synopsis

Documentation

module DDC.Type.Exp

Expressions

data Exp a n Source

Well-typed expressions have types of kind Data.

Constructors

XVar !a !(Bound n)	Value variable or primitive operation.
XCon !a !(DaCon n)	Data constructor or literal.
XLAM !a !(Bind n) !(Exp a n)	Type abstraction (level-1).
XLam !a !(Bind n) !(Exp a n)	Value and Witness abstraction (level-0).
XApp !a !(Exp a n) !(Exp a n)	Application.
XLet !a !(Lets a n) !(Exp a n)	Possibly recursive bindings.
XCase !a !(Exp a n) ![Alt a n]	Case branching.
XCast !a !(Cast a n) !(Exp a n)	Type cast.
XType !a !(Type n)	Type can appear as the argument of an application.
XWitness !a !(Witness a n)	Witness can appear as the argument of an application.
XDefix !a [Exp a n]	Some expressions and infix operators that need to be resolved into proper function applications.
XInfixOp !a String	Use of a naked infix operator, like in 1 + 2. INVARIANT: only appears in the list of an XDefix node.
XInfixVar !a String	Use of an infix operator as a plain variable, like in (+) 1 2. INVARIANT: only appears in the list of an XDefix node.

Instances

Defix Exp
Expand Exp
(Eq a, Eq n) => Eq (Exp a n)
(Show a, Show n) => Show (Exp a n)
(Pretty n, Eq n) => Pretty (Exp a n)
(NFData a, NFData n) => NFData (Exp a n)

data Lets a n Source

Possibly recursive bindings.

Constructors

LLet !(Bind n) !(Exp a n)	Non-recursive let-binding.
LRec ![(Bind n, Exp a n)]	Recursive let bindings.
LPrivate ![Bind n] !(Maybe (Type n)) ![Bind n]	Bind a local region variable, and witnesses to its properties.

Instances

Defix Lets
(Eq a, Eq n) => Eq (Lets a n)
(Show a, Show n) => Show (Lets a n)
(Pretty n, Eq n) => Pretty (Lets a n)
(NFData a, NFData n) => NFData (Lets a n)

data Alt a n Source

Case alternatives.

Constructors

AAlt !(Pat n) !(Exp a n)

Instances

Defix Alt
Expand Alt
(Eq a, Eq n) => Eq (Alt a n)
(Show a, Show n) => Show (Alt a n)
(Pretty n, Eq n) => Pretty (Alt a n)
(NFData a, NFData n) => NFData (Alt a n)

data Pat n

Pattern matching.

Constructors

PDefault	The default pattern always succeeds.
PData !(DaCon n) ![Bind n]	Match a data constructor and bind its arguments.

Instances

Eq n => Eq (Pat n)
Show n => Show (Pat n)
(Pretty n, Eq n) => Pretty (Pat n)
NFData n => NFData (Pat n)

data Cast a n Source

Type casts.

Constructors

CastWeakenEffect !(Effect n)	Weaken the effect of an expression. The given effect is added to the effect of the body.
CastPurify !(Witness a n)	Purify the effect (action) of an expression.
CastBox	Box a computation, capturing its effects in the S computation type.
CastRun	Run a computation, releasing its effects into the environment.

Instances

(Eq a, Eq n) => Eq (Cast a n)
(Show a, Show n) => Show (Cast a n)
(Pretty n, Eq n) => Pretty (Cast a n)
(NFData a, NFData n) => NFData (Cast a n)

Witnesses

data Witness a n

When a witness exists in the program it guarantees that a certain property of the program is true.

Constructors

WVar a !(Bound n)	Witness variable.
WCon a !(WiCon n)	Witness constructor.
WApp a !(Witness a n) !(Witness a n)	Witness application.
WJoin a !(Witness a n) !(Witness a n)	Joining of witnesses.
WType a !(Type n)	Type can appear as the argument of an application.

Instances

BindStruct (Witness a)
(Eq a, Eq n) => Eq (Witness a n)
(Show a, Show n) => Show (Witness a n)
(Pretty n, Eq n) => Pretty (Witness a n)
(NFData a, NFData n) => NFData (Witness a n)

Data Constructors

data DaCon n

Data constructors.

Constructors

DaConUnit	Baked in unit data constructor.
DaConPrim	Primitive data constructor used for literals and baked-in constructors. The type of the constructor needs to be attached to handle the case where there are too many constructors in the data type to list, like for Int literals. In this case we determine what data type it belongs to from the attached type of the data constructor.
Fields daConName :: !n Name of the data constructor. Name of the data constructor. daConType :: !(Type n) Type of the data constructor.
DaConBound	Data constructor that has a data type declaration.
Fields daConName :: !n Name of the data constructor. Name of the data constructor.

Instances

Eq n => Eq (DaCon n)
Show n => Show (DaCon n)
(Pretty n, Eq n) => Pretty (DaCon n)
NFData n => NFData (DaCon n)

Witness Constructors

data WiCon n

Witness constructors.

Constructors

WiConBuiltin !WbCon	Witness constructors baked into the language.
WiConBound !(Bound n) !(Type n)	Witness constructors defined in the environment. In the interpreter we use this to hold runtime capabilities. The attached type must be closed.

Instances

Eq n => Eq (WiCon n)
Show n => Show (WiCon n)
(Pretty n, Eq n) => Pretty (WiCon n)
NFData n => NFData (WiCon n)

data WbCon

Built-in witness constructors.

These are used to convert a runtime capability into a witness that the corresponding property is true.

Constructors

WbConPure	(axiom) The pure effect is pure. pure :: Pure !0
WbConEmpty	(axiom) The empty closure is empty. empty :: Empty $0
WbConUse	Convert a capability guaranteeing that a region is in the global heap, into a witness that a closure using this region is empty. This lets us rely on the garbage collector to reclaim objects in the region. It is needed when we suspend the evaluation of expressions that have a region in their closure, because the type of the returned thunk may not reveal that it references objects in that region. use :: [r : %]. Global r => Empty (Use r)
WbConRead	Convert a capability guaranteeing the constancy of a region, into a witness that a read from that region is pure. This lets us suspend applications that read constant objects, because it doesn't matter if the read is delayed, we'll always get the same result. read :: [r : %]. Const r => Pure (Read r)
WbConAlloc	Convert a capability guaranteeing the constancy of a region, into a witness that allocation into that region is pure. This lets us increase the sharing of constant objects, because we can't tell constant objects of the same value apart. alloc :: [r : %]. Const r => Pure (Alloc r)

Instances

Eq WbCon
Show WbCon
Pretty WbCon
NFData WbCon