Class AcceptableInheritanceDepthOrError

java.lang.Object

org.ek9lang.compiler.phase5.AcceptableInheritanceDepthOrError

All Implemented Interfaces:

Consumer<org.antlr.v4.runtime.tree.ParseTree>

class AcceptableInheritanceDepthOrError
extends Object
implements Consumer<org.antlr.v4.runtime.tree.ParseTree>

Checks inheritance depth (DIT) against thresholds and emits errors if exceeded. Based on Chidamber & Kemerer (1994) CK Metrics Suite.

Deep inheritance hierarchies cause the "fragile base class problem" where changes to ancestors cascade unpredictably to descendants. EK9 promotes the use of delegation via the 'by' keyword as a superior alternative.

Thresholds are set slightly below industry standard (4 vs 5-6) because EK9 provides the 'by' delegation mechanism as a built-in alternative:

• class: max 4 (allows Base -> Abstract -> Concrete -> Specialization)
• record: max 2 (data-focused, minimal behavior inheritance)
• trait: max 4 (interface hierarchies)
• component: max 4 (entry points)
• function: max 3 (function inheritance is rare)

Constructor Summary

Constructors

Constructor	Description
AcceptableInheritanceDepthOrError(SymbolsAndScopes symbolsAndScopes, ErrorListener errorListener)

Method Summary

Modifier and Type	Method	Description
void	accept(org.antlr.v4.runtime.tree.ParseTree node)

Methods inherited from class Object

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

Methods inherited from interface Consumer

andThen

Constructor Details

AcceptableInheritanceDepthOrError

AcceptableInheritanceDepthOrError(SymbolsAndScopes symbolsAndScopes,
 ErrorListener errorListener)

Method Details

accept

public void accept(org.antlr.v4.runtime.tree.ParseTree node)

Specified by:

accept in interface Consumer<org.antlr.v4.runtime.tree.ParseTree>