hlt.language.design.types

Class Symbol

java.lang.Object

hlt.language.design.types.Symbol

public class Symbol
extends java.lang.Object

A symbol object is essentially a (global) name and its type table. The type table is a list of CodeEntry objects.

Field Summary

Fields

Modifier and Type	Field and Description
static Symbol	COLLECTION This is a dummy symbol that is given the types allowed for collections.
static Symbol	INDEX_SET This is a dummy symbol that is given the types allowed for array index sets.
static Symbol	INDEXABLE This is a dummy symbol that is given the types allowed for map index sets.

Constructor Summary

Constructors

Constructor and Description
Symbol(java.lang.String name)
Symbol(java.lang.String name, int index)

Method Summary

Methods

Modifier and Type	Method and Description
void	defineBuiltIn(Type type, Instruction builtIn) Installs this symbol as a built-in with specified type and instruction.
boolean	equals(java.lang.Object other)
CodeEntry	getCodeEntry(Type type) Assigns and returns a CodeEntry corresponding to the specified Type for this symbol if one does not exist for with this type; otherwise, returns the existing one.
CodeEntry	getCodeEntry(Type type, boolean noDuplicates) Assigns and returns a CodeEntry corresponding to the specified Type for this symbol if one does not exist for with this type.
int	index()
boolean	isDefined()
boolean	isDefined(Type type)
java.lang.String	name()
DefinedEntry	registerCodeEntry(Type type) This method registers a definitively checked type of this global symbol.
void	removeLatestEntry() Removes the latest code entry in this symbol's type table.
Symbol	setNoCurrying(boolean flag)
void	showCodeEntries()
void	showDefinedEntries()
java.lang.String	toString()
ArrayList	typeTable()

Methods inherited from class java.lang.Object

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

Field Detail

INDEX_SET

public static final Symbol INDEX_SET

This is a dummy symbol that is given the types allowed for array index sets. It is used for type-checking array dimension expressions for allocation via a dummy Global constructed with this symbol, thus enabling a choice point to be created for typing these expressions.

INDEXABLE

public static final Symbol INDEXABLE

This is a dummy symbol that is given the types allowed for map index sets. It is used for type-checking array dimension expressions for allocation via a dummy Global constructed with this symbol, thus enabling a choice point to be created for typing these expressions.

COLLECTION

public static final Symbol COLLECTION

This is a dummy symbol that is given the types allowed for collections. It is used for type-checking it using a dummy Global constructed with this symbol, thus enabling choice points to be created for typing its expression.

Constructor Detail

Symbol

public Symbol(java.lang.String name)

Symbol

public Symbol(java.lang.String name,
      int index)

Method Detail

name

public final java.lang.String name()

index

public final int index()

typeTable

public final ArrayList typeTable()

setNoCurrying

public final Symbol setNoCurrying(boolean flag)

registerCodeEntry

public final DefinedEntry registerCodeEntry(Type type)
                                     throws DefinitionException

This method registers a definitively checked type of this global symbol. It is meant to be called only (and it is) by its namesake method in the class Definition, itself only called after type-checking of this symbol's definition has been completed; namely, after the setCheckedType method has been invoked on the definition, which ensures that its type argument has been standardized.

Throws:

DefinitionException

getCodeEntry

public final CodeEntry getCodeEntry(Type type)

Assigns and returns a CodeEntry corresponding to the specified Type for this symbol if one does not exist for with this type; otherwise, returns the existing one.

getCodeEntry

public final CodeEntry getCodeEntry(Type type,
                     boolean noDuplicates)
                             throws DuplicateCodeEntryException

Assigns and returns a CodeEntry corresponding to the specified Type for this symbol if one does not exist for with this type. If the noDuplicates is true, a DuplicateCodeEntryException is thrown whenever an entry already existed for this type; otherwise, returns the existing code entry.

Throws:

DuplicateCodeEntryException

removeLatestEntry

public final void removeLatestEntry()

Removes the latest code entry in this symbol's type table.

defineBuiltIn

public final void defineBuiltIn(Type type,
                 Instruction builtIn)
                         throws DuplicateCodeEntryException

Installs this symbol as a built-in with specified type and instruction. N.B.: If this type was defined for this symbol before, a DuplicateCodeEntryException is thrown.

Throws:

DuplicateCodeEntryException

isDefined

public final boolean isDefined()

isDefined

public final boolean isDefined(Type type)

equals

public final boolean equals(java.lang.Object other)

Overrides:

equals in class java.lang.Object

showDefinedEntries

public final void showDefinedEntries()

showCodeEntries

public final void showCodeEntries()

toString

public final java.lang.String toString()

Overrides:

toString in class java.lang.Object