hlt.language.design.kernel

Class Scope

java.lang.Object

hlt.language.design.kernel.Expression

hlt.language.design.kernel.ProtoExpression

hlt.language.design.kernel.Scope

All Implemented Interfaces:

Locatable

Direct Known Subclasses:

Abstraction

public class Scope
extends ProtoExpression

This class represents a scope for local variables. It may be seen as a lambda abstraction that never needs to be lexically closed. It is used for creating a Let block as the application of such a Scope to its local variable's initial values. As a result, it can never be exported outside its enclosing scope, and therefore it can dispense with the whole machinery of creating and maintaining lexical frames. Also, a scope does not allow non-local exits.

NB: This class is not meant to be put in unknowing hands: using it without being fully aware of its functionality may cause seriously wrong behavior - if you do not know for sure that this is what you want, then use Abstraction instead!

Field Summary

Fields inherited from class hlt.language.design.kernel.Expression

VOID_ASSIGNMENTS

Constructor Summary

Constructors

Constructor and Description
Scope(java.util.AbstractList parameters, Expression body)
Scope(Expression body)
Scope(Parameter[] parameters, Expression body)
Scope(Parameter parameter, Expression body)
Scope(java.lang.String name, Expression body)

Method Summary

Methods

Modifier and Type	Method and Description
int	arity()
Expression	body()
void	compile(Compiler compiler) This method compiles this expression in the context of the specified Compiler.
boolean	containsFreeName(java.lang.String name) Returns true iff the specified name occurs free in this expression.
Expression	copy() Returns a deep copy of this expression.
Expression	enclosingScope() Returns this expression enclosing scope (if it has been computed by linkScopeTree); null otherwise.
int	intArity()
int	numberOfSubexpressions() Returns the number of subexpressions
int	objectArity()
Parameter	parameter(int i)
Parameter[]	parameters() This is only to enable uniform visitors on expressions.
int	realArity()
Expression	sanitizeNames(ParameterStack parameters) This method returns the actual expression corresponding to this one after eliminating all the Dummy expressions that occur in it where names where read.
void	sanitizeSorts(Enclosure enclosure) This method walks down the expression gathering information relating each Local object to the Scope containing the corresponding Parameter in its array of formal parameters.
void	setBody(Expression body)
void	setCheckedType() This method sets the final unambiguously checked type of this expression, possibly along with other final information that may be needed by the compiler for generating code.
void	setCheckedType(Type type) NB: this is not final because itis overridden in Abstraction and Global.
void	setSortedArities()
Expression	setSubexpression(int n, Expression expression) Returns this expression after setting its n-th subexpression to the specified expression; if there is no subexpression at the given position, this throws a NoSuchSubexpressionException
Expression	shiftOffsets(int intShift, int realShift, int objectShift, int intDepth, int realDepth, int objectDepth) This methods visits this expression shifting the offset of all the Locals it encounters by the specified amount (per sort) as long as the offset it sees is referencing a parameter within the specified scope depth (per sort); This method is used when the compiler needs to synthesize an scope from an already typechecked expression (i.e., for currying or un/boxing - e.g., see the pad method below).
Expression	subexpression(int n) Returns the n-th subexpression of this expression; if there is no subexpression at the given position, this throws a NoSuchSubexpressionException
Expression	substitute(java.util.HashMap substitution) Returns the expression resulting from substituting all the free occurrences of the parameters's names as specified by the given substitution.
java.lang.String	toString()
void	typeCheck(TypeChecker typeChecker) This method type-checks this expression in the context of the specified TypeChecker.
Expression	typedCopy() Returns a deep copy of this expression this and all its subexpressions share the same type as their copy's counterparts.
int	voidArity()

Methods inherited from class hlt.language.design.kernel.ProtoExpression

checkedType, setType, type, typeRef

Methods inherited from class hlt.language.design.kernel.Expression

addType, addTypes, boxSort, extent, getEnd, getStart, isConstant, isEquality, isFalse, isHiddenSlicing, isNull, isSelector, isSlicing, isTrue, isVoid, locationString, otherTypes, setCheckedTypeLocked, setEnd, setExtent, setOtherTypes, setStart, shiftOffsets, sort, typeCheck, typeCheck, typeCheckLocked

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Scope

public Scope(Parameter[] parameters,
     Expression body)

Scope

public Scope(Parameter parameter,
     Expression body)

Scope

public Scope(java.lang.String name,
     Expression body)

Scope

public Scope(Expression body)

Scope

public Scope(java.util.AbstractList parameters,
     Expression body)

Method Detail

copy

public Expression copy()

Description copied from class: Expression

Returns a deep copy of this expression. The types are not not copied. NB: This is a convenience for building expressions that should be used exclusively before any processing (in particular sanitizing), is done on this expression.

Specified by:

copy in class Expression

typedCopy

public Expression typedCopy()

Description copied from class: Expression

Returns a deep copy of this expression this and all its subexpressions share the same type as their copy's counterparts. NB: This is a convenience for building expressions that should be used exclusively before any processing (in particular sanitizing), is done on this expression.

Specified by:

typedCopy in class Expression

arity

public final int arity()

intArity

public final int intArity()

realArity

public final int realArity()

objectArity

public final int objectArity()

voidArity

public final int voidArity()

setSortedArities

public final void setSortedArities()

numberOfSubexpressions

public final int numberOfSubexpressions()

Description copied from class: Expression

Returns the number of subexpressions

Overrides:

numberOfSubexpressions in class Expression

subexpression

public final Expression subexpression(int n)
                               throws NoSuchSubexpressionException

Description copied from class: Expression

Returns the n-th subexpression of this expression; if there is no subexpression at the given position, this throws a NoSuchSubexpressionException

Overrides:

subexpression in class Expression

Throws:

NoSuchSubexpressionException

setSubexpression

public final Expression setSubexpression(int n,
                          Expression expression)
                                  throws NoSuchSubexpressionException

Description copied from class: Expression

Returns this expression after setting its n-th subexpression to the specified expression; if there is no subexpression at the given position, this throws a NoSuchSubexpressionException

Overrides:

setSubexpression in class Expression

Throws:

NoSuchSubexpressionException

parameters

public final Parameter[] parameters()

Description copied from class: Expression

This is only to enable uniform visitors on expressions. It will return non-null only for scopes.

Overrides:

parameters in class Expression

parameter

public final Parameter parameter(int i)

body

public final Expression body()

setBody

public final void setBody(Expression body)

setCheckedType

public final void setCheckedType(Type type)

Description copied from class: ProtoExpression

NB: this is not final because itis overridden in Abstraction and Global.

Overrides:

setCheckedType in class ProtoExpression

setCheckedType

public final void setCheckedType()

Description copied from class: Expression

This method sets the final unambiguously checked type of this expression, possibly along with other final information that may be needed by the compiler for generating code.

Specified by:

setCheckedType in class Expression

typeCheck

public void typeCheck(TypeChecker typeChecker)
               throws TypingErrorException

Description copied from class: Expression

This method type-checks this expression in the context of the specified TypeChecker.

Specified by:

typeCheck in class Expression

Throws:

TypingErrorException

containsFreeName

public final boolean containsFreeName(java.lang.String name)

Description copied from class: Expression

Returns true iff the specified name occurs free in this expression.

Overrides:

containsFreeName in class Expression

enclosingScope

public final Expression enclosingScope()

Description copied from class: Expression

Returns this expression enclosing scope (if it has been computed by linkScopeTree); null otherwise.

Overrides:

enclosingScope in class Expression

substitute

public Expression substitute(java.util.HashMap substitution)

Description copied from class: Expression

Returns the expression resulting from substituting all the free occurrences of the parameters's names as specified by the given substitution.

Overrides:

substitute in class Expression

sanitizeNames

public final Expression sanitizeNames(ParameterStack parameters)

Description copied from class: Expression

This method returns the actual expression corresponding to this one after eliminating all the Dummy expressions that occur in it where names where read. It takes as an argument the stack of parameters it encounters along the way of visiting all its components. A ParameterStack is simply a Stack of Parameter objects along with a method to retrieve the latest one with a given name.

Overrides:

sanitizeNames in class Expression

sanitizeSorts

public void sanitizeSorts(Enclosure enclosure)

Description copied from class: Expression

This method walks down the expression gathering information relating each Local object to the Scope containing the corresponding Parameter in its array of formal parameters. It takes as an argument an Enclosure, which is a Stack containing all Scopes encountered along the way, equipped with a method to compute all the information necessary in computing the local's offset.

Overrides:

sanitizeSorts in class Expression

shiftOffsets

public Expression shiftOffsets(int intShift,
                      int realShift,
                      int objectShift,
                      int intDepth,
                      int realDepth,
                      int objectDepth)

Description copied from class: Expression

This methods visits this expression shifting the offset of all the Locals it encounters by the specified amount (per sort) as long as the offset it sees is referencing a parameter within the specified scope depth (per sort); This method is used when the compiler needs to synthesize an scope from an already typechecked expression (i.e., for currying or un/boxing - e.g., see the pad method below).

Overrides:

shiftOffsets in class Expression

compile

public final void compile(Compiler compiler)

Description copied from class: Expression

This method compiles this expression in the context of the specified Compiler.

Specified by:

compile in class Expression

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object