wytp.types

Interface TypeInferer.Environment

All Known Implementing Classes:

StdTypeEnvironment

Enclosing interface:

TypeInferer

public static interface TypeInferer.Environment

The typing environment determines the current type for all variables at a given point. Observe that the type given to a variable may differ from its declared type in certain contexts. For example, support variable x is declared to have type int|null. Then, in a specific context we may have x is int and, in which case, we can refine the known type for x accodingly.

Author:

David J. Pearce

Method Summary

Modifier and Type	Method and Description
Set<WyalFile.VariableDeclaration>	getRefinedVariables()
WyalFile.Type	getType(WyalFile.VariableDeclaration var) Return the current type associated with a given variable.
TypeInferer.Environment	refineType(WyalFile.VariableDeclaration var, WyalFile.Type type) Refine the type associated with a given variable declaration in this environment, which produces a completely new environment containing the refined type.

Method Detail

getType

WyalFile.Type getType(WyalFile.VariableDeclaration var)

Return the current type associated with a given variable. It is generally assumed that this either matches its declared type, or is a refinement thereof.

Parameters:

var -

Returns:

refineType

TypeInferer.Environment refineType(WyalFile.VariableDeclaration var,
                                   WyalFile.Type type)

Refine the type associated with a given variable declaration in this environment, which produces a completely new environment containing the refined type. Observe that the variable need not have been previously declared for this to make sense. Also, observe that the resulting type for a given variable is the intersection of its original type and the refined type.

Parameters:

var -

type -

Returns:

getRefinedVariables

Set<WyalFile.VariableDeclaration> getRefinedVariables()