Class RemovedCoalescingOperatorOrError

java.lang.Object

org.ek9lang.compiler.phase1.RemovedCoalescingOperatorOrError

All Implemented Interfaces:

Consumer<EK9Parser.ExpressionContext>

final class RemovedCoalescingOperatorOrError
extends Object
implements Consumer<EK9Parser.ExpressionContext>

E01095 (Steve, 2026-10-21, sameness wave 2, section 4.9 b1): the comparison coalescing operators <=? and >=? were removed. On equal values (<=> gives 0) <? and >? now give the LEFT operand, which is what <=? and >=? gave, so each has a plain replacement: <? for <=? and >? for >=?. (To get the RIGHT operand on a tie, swap the operands.)

The grammar keeps recognising the two tokens ONLY to give this error, as it keeps break and return (E0107x); a program that uses one stops here, in phase 1, with a message that names the replacement.

E01096 (Steve, 2026-10-21) is the same for ??, the null coalescing operator: EK9 is designed so that no value is absent, leaving it nothing to test, so x ?? y would give x (D75). It is reported at the ?? token, once per use.

??= (the null coalescing assignment, C#, JavaScript, PHP) is removed with it, under the same E01096: the message names :=? (assign only if currently unset), the assignment that tests unset rather than absent. It is reported by onAssignment(EK9Parser.AssignmentStatementContext) at the ??= token.

isRemoved(Token) is THE test for one of the four tokens: a phase-1 check that would report AT such a token for another reason (E08269 reports a coalescing operand from the enclosing expression, before this one is entered) leaves it to this error, so the first error at the place says what is wrong.

Constructor Summary

Constructors

Constructor	Description
RemovedCoalescingOperatorOrError(ErrorListener errorListener)

Method Summary

Modifier and Type	Method	Description
void	accept(EK9Parser.ExpressionContext ctx)
(package private) static boolean	isRemoved(org.antlr.v4.runtime.Token operator)	Is this token one of the removed coalescing operators (<=?, >=?, ?? or ??=)?
(package private) void	onAssignment(EK9Parser.AssignmentStatementContext ctx)	The assignment form: x ??= y reports E01096 at the ??=, naming :=?.

Methods inherited from class Object

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

Methods inherited from interface Consumer

andThen

Constructor Details

RemovedCoalescingOperatorOrError

RemovedCoalescingOperatorOrError(ErrorListener errorListener)

Method Details

isRemoved

static boolean isRemoved(org.antlr.v4.runtime.Token operator)

Is this token one of the removed coalescing operators (<=?, >=?, ?? or ??=)?

onAssignment

void onAssignment(EK9Parser.AssignmentStatementContext ctx)

The assignment form: x ??= y reports E01096 at the ??=, naming :=?. Never auto-repaired: ??= tests absence, :=? tests unset.

accept

public void accept(EK9Parser.ExpressionContext ctx)

Specified by:

accept in interface Consumer<EK9Parser.ExpressionContext>