Unifier Class Reference

Class used to solve type constraints and establish typability. More...

#include <Unifier.h>

Public Member Functions
	Unifier ()
	Unifier (std::vector< TypeConstraint >)
	Construct a Unifier with seeded with constraints. More...
	~Unifier ()=default
	Construct an empty Unifier. More...
void	unify (std::shared_ptr< TipType > t1, std::shared_ptr< TipType > t2)
	Attempt to unify the two types. More...
void	add (std::vector< TypeConstraint >)
	Add constraints to this unifier. More...
void	solve ()
	Solve the system of constraints that have presented to this unifier. More...
std::shared_ptr< TipType >	inferred (std::shared_ptr< TipType > t)
	Returns the inferred type for a given type. More...

Static Public Member Functions
static bool	isCons (std::shared_ptr< TipType > type)
static bool	isMu (std::shared_ptr< TipType > type)
static bool	isVar (std::shared_ptr< TipType > type)
static bool	isAlpha (std::shared_ptr< TipType > type)
static bool	isProperType (std::shared_ptr< TipType > type)

Detailed Description

Class used to solve type constraints and establish typability.

Make uses of a union-find data structure. This class will throw a UnificationError anytime two terms cannot be unified, either because their constructor or arity mismatch.

Constructor & Destructor Documentation

Unifier() [1/2]

Unifier::Unifier

(

)

Unifier() [2/2]

Unifier::Unifier ( std::vector< TypeConstraint >  constrs )

explicit

Construct a Unifier with seeded with constraints.

Useful for when one is collecting and then unifying constraints.

~Unifier()

Unifier::~Unifier ( )

default

Construct an empty Unifier.

Useful for when unifying on the fly.

Member Function Documentation

add()

void Unifier::add

(

std::vector< TypeConstraint >

constrs

)

Add constraints to this unifier.

inferred()

std::shared_ptr< TipType > Unifier::inferred

(

std::shared_ptr< TipType >

v

)

Returns the inferred type for a given type.

Looks up the inferred type in the type solution.

Precondition

The unifier has computed a solution. This will close the type by replacing any variables that are bound to proper types in the inferred solution with that proper type.

Here we want to produce an inferred type that is "closed" in the sense that all variables in the type definition are replaced with their base types. The close() function may update the unionFind structure, by generating new types, and this is essential for the staged nature of polymorphic type inference.

isAlpha()

bool Unifier::isAlpha ( std::shared_ptr< TipType >  type )

static

isCons()

bool Unifier::isCons ( std::shared_ptr< TipType >  type )

static

isMu()

bool Unifier::isMu ( std::shared_ptr< TipType >  type )

static

isProperType()

bool Unifier::isProperType ( std::shared_ptr< TipType >  type )

static

isVar()

bool Unifier::isVar ( std::shared_ptr< TipType >  type )

static

solve()

void Unifier::solve

(

)

Solve the system of constraints that have presented to this unifier.

Precondition

The unifier has been constructed with seed values. Incremental solving can be achieved by adding constraints, via the add method, after solving. This will cause the new constraints to be unified with the currently unified constraints.

unify()

void Unifier::unify	(	std::shared_ptr< TipType >	t1,
		std::shared_ptr< TipType >	t2
	)

Attempt to unify the two types.

Exceptions

UnificationError

when constraints cannot be unifierd.

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The documentation for this class was generated from the following files:

• /home/runner/work/tipc/tipc/src/semantic/types/solver/Unifier.h
• /home/runner/work/tipc/tipc/src/semantic/types/solver/Unifier.cpp