Class PossibleExpressionConstruct

java.lang.Object

org.ek9lang.compiler.common.RuleSupport

org.ek9lang.compiler.common.TypedSymbolAccess

org.ek9lang.compiler.phase5.PossibleExpressionConstruct

Direct Known Subclasses:

ForStatementOrError, SwitchStatementOrError, TryStatementOrError, WhileStatementOrError

abstract class PossibleExpressionConstruct
extends TypedSymbolAccess

Used as a base for a range of constructs that can be expressions.

Field Summary

Fields inherited from class RuleSupport

errorListener, symbolsAndScopes

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	PossibleExpressionConstruct(SymbolsAndScopes symbolsAndScopes, ErrorListener errorListener)

Method Summary

Modifier and Type	Method	Description
protected Optional<ISymbol>	getGuardExpressionVariable(EK9Parser.PreFlowAndControlContext ctx)
protected Optional<ISymbol>	getGuardExpressionVariable(EK9Parser.PreFlowStatementContext ctx)
protected boolean	isVariableInitialisedInScopes(CodeFlowAnalyzer analyzer, ISymbol variable, List<IScope> scopes)
protected void	processPossibleGuardInitialisation(CodeFlowAnalyzer analyzer, ISymbol guardVariable, org.antlr.v4.runtime.ParserRuleContext ctx)	Now when there is a preflow control, it may mean that a variable is initialised.
protected void	pullUpAcceptableCriteriaToHigherScope(CodeFlowAnalyzer analyzer, List<IScope> allAppropriateBlocks, IScope outerScope)
protected void	returningVariableValidOrError(EK9Parser.ReturningParamContext ctx, IScope constructScope, boolean bodyGuaranteedToRun)	Validates the returning variable of an expression-form construct.

Methods inherited from class TypedSymbolAccess

getRecordedAndTypedSymbol, isProcessingScopePure, recordATypedSymbol

Methods inherited from class Object

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

Constructor Details

PossibleExpressionConstruct

protected PossibleExpressionConstruct(SymbolsAndScopes symbolsAndScopes,
 ErrorListener errorListener)

Method Details

isVariableInitialisedInScopes

protected boolean isVariableInitialisedInScopes(CodeFlowAnalyzer analyzer,
 ISymbol variable,
 List<IScope> scopes)

getGuardExpressionVariable

protected Optional<ISymbol> getGuardExpressionVariable(EK9Parser.PreFlowStatementContext ctx)

getGuardExpressionVariable

protected Optional<ISymbol> getGuardExpressionVariable(EK9Parser.PreFlowAndControlContext ctx)

processPossibleGuardInitialisation

protected void processPossibleGuardInitialisation(CodeFlowAnalyzer analyzer,
 ISymbol guardVariable,
 org.antlr.v4.runtime.ParserRuleContext ctx)

Now when there is a preflow control, it may mean that a variable is initialised.

pullUpAcceptableCriteriaToHigherScope

protected void pullUpAcceptableCriteriaToHigherScope(CodeFlowAnalyzer analyzer,
 List<IScope> allAppropriateBlocks,
 IScope outerScope)

returningVariableValidOrError

protected void returningVariableValidOrError(EK9Parser.ReturningParamContext ctx,
 IScope constructScope,
 boolean bodyGuaranteedToRun)

Validates the returning variable of an expression-form construct.

When the body is NOT guaranteed to run - a body-skipping guard (<-/?=/:=?, see PreFlowCanSkipBody) can bypass it, or a loop can iterate zero times - a return declared with no initial value (<- rtn as T?) could be left unset on the skip path, so it MUST carry a declaration initialiser. Enforced uniformly across switch/while/do/for/try (before this it fired only for ?= on some constructs and relied on a per-construct backstop, which let switch/for/for-range leak a raw Java null into the LHS at runtime).