Class InjectedSetCheckOrError

java.lang.Object

org.ek9lang.compiler.common.RuleSupport

org.ek9lang.compiler.phase3.InjectedSetCheckOrError

final class InjectedSetCheckOrError
extends RuleSupport

An injected component is always set, so any check that it is set is always true - dead code that reads as though the injection might not arrive (E08266). EK9 eliminates it rather than discouraging it.

The checks: injected? wherever it appears (an if/while condition, require, assert, a ternary's control, a returning value, inside not); the coalescing operators injected ?? other and injected ?: other, which fall back only when the left is unset or absent; and a guard whose value is the injected variable itself (if svc <- injected, ?=, :=), whose body always runs.

"Injected" is a variable or property declared name as T!: the symbol the operand resolves to ISymbol.isInjectionExpected(). A value COPIED from it into another variable is an ordinary variable - that is the fallback idiom: chosen <- supplied then chosen :=? injected. Assigning to the injected variable itself, :=? included, is E08170.

Field Summary

Fields inherited from class RuleSupport

errorListener, symbolsAndScopes

Constructor Summary

Constructors

Constructor	Description
InjectedSetCheckOrError(SymbolsAndScopes symbolsAndScopes, ErrorListener errorListener)

Method Summary

Modifier and Type	Method	Description
(package private) void	accept(EK9Parser.ExpressionContext ctx)	injected?, injected ?? other, injected ?: other.
(package private) void	accept(EK9Parser.PreFlowStatementContext ctx)	A guard whose value is the injected variable: if svc <- injected, if svc ?= injected.

Methods inherited from class Object

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

Constructor Details

InjectedSetCheckOrError

InjectedSetCheckOrError(SymbolsAndScopes symbolsAndScopes,
 ErrorListener errorListener)

Method Details

accept

void accept(EK9Parser.ExpressionContext ctx)

injected?, injected ?? other, injected ?: other.

accept

void accept(EK9Parser.PreFlowStatementContext ctx)

A guard whose value is the injected variable: if svc <- injected, if svc ?= injected.