Class UnsetKeepingOperator

java.lang.Object

org.ek9lang.compiler.support.UnsetKeepingOperator

public final class UnsetKeepingOperator
extends Object

🔑 THE question "does this in-place operator keep an UNSET receiver unset?" - asked of the RESOLVED operator symbol, never of its spelling or the receiver's type name. True only for an operator carrying KEEPS_UNSET, which the bootstrap squirrels from @Ek9Operator(keepsUnset = true) (+= -= *= /= ++ -- on the literal types; pinned by ek9-lang UnsetFactsTest). A user operator never carries it, so for a user type the answer is always no and the value tracker forgets the value exactly as before.

The search is the one phase 3 made when it resolved the operator (LhsAndRhsAssignmentOrError, StatementOrError): the operator by its written name, with the argument's type when it has one. Phase 3 records nothing for these operators, so a later phase asks here rather than re-deriving the search.

Method Summary

Modifier and Type	Method	Description
static Optional<MethodSymbol>	keepingUnset(ISymbol receiverType, String operator, Optional<ISymbol> argumentType)	As resolve(ISymbol, String, Optional) then keepsUnset(MethodSymbol): the resolved operator, only when it keeps an unset receiver unset.
static boolean	keepsUnset(MethodSymbol operator)	Does the resolved operator keep an unset receiver unset, whatever its argument?
static Optional<MethodSymbol>	resolve(ISymbol receiverType, String operator, Optional<ISymbol> argumentType)	The operator operator resolves to on receiverType given an argument of argumentType (empty for ++ and --), when it resolves to exactly one.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

resolve

public static Optional<MethodSymbol> resolve(ISymbol receiverType,
 String operator,
 Optional<ISymbol> argumentType)

The operator operator resolves to on receiverType given an argument of argumentType (empty for ++ and --), when it resolves to exactly one.

keepsUnset

public static boolean keepsUnset(MethodSymbol operator)

Does the resolved operator keep an unset receiver unset, whatever its argument?

keepingUnset

public static Optional<MethodSymbol> keepingUnset(ISymbol receiverType,
 String operator,
 Optional<ISymbol> argumentType)

As resolve(ISymbol, String, Optional) then keepsUnset(MethodSymbol): the resolved operator, only when it keeps an unset receiver unset.