Class ConstantSymbol

java.lang.Object

org.ek9lang.compiler.symbols.Symbol

org.ek9lang.compiler.symbols.ConstantSymbol

All Implemented Interfaces:

Serializable, ISymbol, ISymbolNature, ITokenReference

public class ConstantSymbol
extends Symbol

A very simple type that holds a single distinct value. For example PI = 3.242 would be a constant.

See Also:

• Serialized Form

Constructor Summary

Constructors

Constructor	Description
ConstantSymbol(String name)
ConstantSymbol(String name, boolean fromLiteral)
ConstantSymbol(String name, Optional<ISymbol> type)
ConstantSymbol(String name, Optional<ISymbol> type, boolean fromLiteral)	Construction of a Constant.
ConstantSymbol(String name, ISymbol type)
ConstantSymbol(String name, ISymbol type, boolean fromLiteral)

Method Summary

Modifier and Type	Method	Description
ConstantSymbol	clone(IScope withParentAsAppropriate)	Clone the symbol and re-parent if this symbol like a method should have a parent.
protected ConstantSymbol	cloneIntoConstant(ConstantSymbol newCopy)
boolean	equals(Object o)	Two symbols are the same symbol when they agree on name, category, genus, mutability AND the declaration site they came from.
int	hashCode()	Mixes in exactly the fields Symbol.equals(Object) compares, and nothing else.
boolean	isConstant()
boolean	isFromLiteral()
String	toString()

Methods inherited from class Symbol

clearInitialisedBy, cloneIntoSymbol, copySymbolProperties, getAssignableCostTo, getAssignableCostTo, getCategory, getFriendlyName, getFullyQualifiedName, getGenus, getInitialisedBy, getName, getParsedModule, getProduceFullyQualifiedName, getSourceToken, getSquirrelledData, getSymbolTypeAsString, getType, getUnCoercedAssignableCostTo, isAssignableTo, isAssignableTo, isDevSource, isEk9Core, isExactSameType, isInjectionExpected, isLibSource, isMarkedPure, isMutable, isNullAllowed, isPromotionSupported, isReferenced, putSquirrelledData, setCategory, setEk9Core, setGenus, setInitialisedBy, setInjectionExpected, setMarkedPure, setName, setNotMutable, setNullAllowed, setParsedModule, setProduceFullyQualifiedName, setReferenced, setSourceToken, setType

Methods inherited from class Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface ISymbol

isDeclaredAsConstant, isExtensionOfInjectable, isIncomingParameter, isInitialised, isInjectable, isLoopVariable, isMarkedAbstract, isPrivate, isPropertyField, isProtected, isPublic, isReturningParameter, setType

Methods inherited from interface ISymbolNature

isApplication, isConceptualTypeParameter, isControl, isFunction, isGenericInNature, isMethod, isParameterisedType, isPrimitiveType, isTemplateFunction, isTemplateType, isType, isVariable

Constructor Details

ConstantSymbol

public ConstantSymbol(String name,
 boolean fromLiteral)

ConstantSymbol

public ConstantSymbol(String name)

ConstantSymbol

public ConstantSymbol(String name,
 ISymbol type,
 boolean fromLiteral)

ConstantSymbol

public ConstantSymbol(String name,
 ISymbol type)

ConstantSymbol

public ConstantSymbol(String name,
 Optional<ISymbol> type)

ConstantSymbol

public ConstantSymbol(String name,
 Optional<ISymbol> type,
 boolean fromLiteral)

Construction of a Constant.

Method Details

isFromLiteral

public boolean isFromLiteral()

isConstant

public boolean isConstant()

clone

public ConstantSymbol clone(IScope withParentAsAppropriate)

Description copied from interface: ISymbol

Clone the symbol and re-parent if this symbol like a method should have a parent. Other symbols like VariableSymbols are un-parented

Specified by:

clone in interface ISymbol

Overrides:

clone in class Symbol

cloneIntoConstant

protected ConstantSymbol cloneIntoConstant(ConstantSymbol newCopy)

equals

public boolean equals(Object o)

Description copied from class: Symbol

Two symbols are the same symbol when they agree on name, category, genus, mutability AND the declaration site they came from.

The source token is part of identity deliberately. Name alone is not enough: symbol names are unqualified here, so two unrelated variables both called count, or two types called Foo in different modules, would otherwise compare equal. The compiler relies on telling those apart - CodeFlowMap keys initialisation state on Map<IScope, Map<ISymbol, SymbolAccess>>, and conflating two same-named declarations there makes flow analysis attribute one variable's initialisation to another.

That distinction used to be present ONLY in Symbol.hashCode(), which is why this looked like it worked: two same-named symbols compared equal yet hashed apart, so hash collections usually - but not reliably - kept them separate, while any direct equals call saw them as one. Encoding it here makes the two agree. See SymbolEqualsHashCodeContractTest.

Overrides:

equals in class Symbol

hashCode

public int hashCode()

Description copied from class: Symbol

Mixes in exactly the fields Symbol.equals(Object) compares, and nothing else.

A hashCode may legitimately use FEWER fields than equals (that only causes collisions, which are correct), but never MORE: any extra field makes two symbols that compare equal land in different buckets, so a HashSet silently holds visible duplicates and a HashMap lookup misses an entry that is present. This method used to mix in purity, which no equals at THIS level consults - purity belongs in FunctionSymbol, the level whose equals compares it. The source token stays, and is now matched by Symbol.equals(Object). See SymbolEqualsHashCodeContractTest.

Overrides:

hashCode in class Symbol

toString

public String toString()

Overrides:

toString in class Symbol